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再来初始化一次

parent 9ab372c0
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imageLoader/src/com/nostra13/universalimageloader/core/assist/ImageScaleType.java 0 → 100644
/*******************************************************************************
* Copyright 2011-2014 Sergey Tarasevich
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.nostra13.universalimageloader.core.assist;
/**
* Type of image scaling during decoding.
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @since 1.5.0
*/
public enum ImageScaleType {
/** Image won't be scaled */
NONE,
/**
* Image will be scaled down only if image size is greater than
* {@linkplain javax.microedition.khronos.opengles.GL10#GL_MAX_TEXTURE_SIZE maximum acceptable texture size}.
* Usually it's 2048x2048.<br />
* If Bitmap is expected to display than it must not exceed this size (otherwise you'll get the exception
* "OpenGLRenderer: Bitmap too large to be uploaded into a texture".<br />
* Image will be subsampled in an integer number of times (1, 2, 3, ...) to maximum texture size of device.
*/
NONE_SAFE,
/**
* Image will be reduces 2-fold until next reduce step make image smaller target size.<br />
* It's <b>fast</b> type and it's preferable for usage in lists/grids/galleries (and other
* {@linkplain android.widget.AdapterView adapter-views}) .<br />
* Relates to {@link android.graphics.BitmapFactory.Options#inSampleSize}<br />
* Note: If original image size is smaller than target size then original image <b>won't</b> be scaled.
*/
IN_SAMPLE_POWER_OF_2,
/**
* Image will be subsampled in an integer number of times (1, 2, 3, ...). Use it if memory economy is quite
* important.<br />
* Relates to {@link android.graphics.BitmapFactory.Options#inSampleSize}<br />
* Note: If original image size is smaller than target size then original image <b>won't</b> be scaled.
*/
IN_SAMPLE_INT,
/**
* Image will scaled-down exactly to target size (scaled width or height or both will be equal to target size;
* depends on {@linkplain android.widget.ImageView.ScaleType ImageView's scale type}). Use it if memory economy is
* critically important.<br />
* <b>Note:</b> If original image size is smaller than target size then original image <b>won't</b> be scaled.<br />
* <br />
* <b>NOTE:</b> For creating result Bitmap (of exact size) additional Bitmap will be created with
* {@link android.graphics.Bitmap#createBitmap(android.graphics.Bitmap, int, int, int, int, android.graphics.Matrix, boolean)
* Bitmap.createBitmap(...)}.<br />
* <b>Cons:</b> Saves memory by keeping smaller Bitmap in memory cache (comparing with IN_SAMPLE... scale types)<br />
* <b>Pros:</b> Requires more memory in one time for creation of result Bitmap.
*/
EXACTLY,
/**
* Image will scaled exactly to target size (scaled width or height or both will be equal to target size; depends on
* {@linkplain android.widget.ImageView.ScaleType ImageView's scale type}). Use it if memory economy is critically
* important.<br />
* <b>Note:</b> If original image size is smaller than target size then original image <b>will be stretched</b> to
* target size.<br />
* <br />
* <b>NOTE:</b> For creating result Bitmap (of exact size) additional Bitmap will be created with
* {@link android.graphics.Bitmap#createBitmap(android.graphics.Bitmap, int, int, int, int, android.graphics.Matrix, boolean)
* Bitmap.createBitmap(...)}.<br />
* <b>Cons:</b> Saves memory by keeping smaller Bitmap in memory cache (comparing with IN_SAMPLE... scale types)<br />
* <b>Pros:</b> Requires more memory in one time for creation of result Bitmap.
*/
EXACTLY_STRETCHED
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/ImageSize.java 0 → 100644
/*******************************************************************************
* Copyright 2011-2013 Sergey Tarasevich
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.nostra13.universalimageloader.core.assist;
/**
* Present width and height values
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @since 1.0.0
*/
public class ImageSize {
private static final int TO_STRING_MAX_LENGHT = 9; // "9999x9999".length()
private static final String SEPARATOR = "x";
private final int width;
private final int height;
public ImageSize(int width, int height) {
this.width = width;
this.height = height;
}
public ImageSize(int width, int height, int rotation) {
if (rotation % 180 == 0) {
this.width = width;
this.height = height;
} else {
this.width = height;
this.height = width;
}
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
/** Scales down dimensions in <b>sampleSize</b> times. Returns new object. */
public ImageSize scaleDown(int sampleSize) {
return new ImageSize(width / sampleSize, height / sampleSize);
}
/** Scales dimensions according to incoming scale. Returns new object. */
public ImageSize scale(float scale) {
return new ImageSize((int) (width * scale), (int) (height * scale));
}
@Override
public String toString() {
return new StringBuilder(TO_STRING_MAX_LENGHT).append(width).append(SEPARATOR).append(height).toString();
}
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/LoadedFrom.java 0 → 100644
package com.nostra13.universalimageloader.core.assist;
/**
* Source image loaded from.
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
*/
public enum LoadedFrom {
NETWORK, DISC_CACHE, MEMORY_CACHE
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/QueueProcessingType.java 0 → 100644
/*******************************************************************************
* Copyright 2011-2013 Sergey Tarasevich
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.nostra13.universalimageloader.core.assist;
/**
* Queue processing type which will be used for display task processing
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @since 1.6.3
*/
public enum QueueProcessingType {
FIFO, LIFO
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/ViewScaleType.java 0 → 100644
/*******************************************************************************
* Copyright 2011-2013 Sergey Tarasevich
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.nostra13.universalimageloader.core.assist;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
/**
* Simplify {@linkplain ScaleType ImageView's scale type} to 2 types: {@link #FIT_INSIDE} and {@link #CROP}
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @since 1.6.1
*/
public enum ViewScaleType {
/**
* Scale the image uniformly (maintain the image's aspect ratio) so that at least one dimension (width or height) of
* the image will be equal to or less the corresponding dimension of the view.
*/
FIT_INSIDE,
/**
* Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the
* image will be equal to or larger than the corresponding dimension of the view.
*/
CROP;
/**
* Defines scale type of ImageView.
*
* @param imageView {@link ImageView}
* @return {@link #FIT_INSIDE} for
* <ul>
* <li>{@link ScaleType#FIT_CENTER}</li>
* <li>{@link ScaleType#FIT_XY}</li>
* <li>{@link ScaleType#FIT_START}</li>
* <li>{@link ScaleType#FIT_END}</li>
* <li>{@link ScaleType#CENTER_INSIDE}</li>
* </ul>
* {@link #CROP} for
* <ul>
* <li>{@link ScaleType#CENTER}</li>
* <li>{@link ScaleType#CENTER_CROP}</li>
* <li>{@link ScaleType#MATRIX}</li>
* </ul>
*/
public static ViewScaleType fromImageView(ImageView imageView) {
switch (imageView.getScaleType()) {
case FIT_CENTER:
case FIT_XY:
case FIT_START:
case FIT_END:
case CENTER_INSIDE:
return FIT_INSIDE;
case MATRIX:
case CENTER:
case CENTER_CROP:
default:
return CROP;
}
}
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/deque/BlockingDeque.java 0 → 100644
/*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/licenses/publicdomain
*/
package com.nostra13.universalimageloader.core.assist.deque;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
/**
* A {@link Deque} that additionally supports blocking operations that wait
* for the deque to become non-empty when retrieving an element, and wait for
* space to become available in the deque when storing an element.
*
* <p><tt>BlockingDeque</tt> methods come in four forms, with different ways
* of handling operations that cannot be satisfied immediately, but may be
* satisfied at some point in the future:
* one throws an exception, the second returns a special value (either
* <tt>null</tt> or <tt>false</tt>, depending on the operation), the third
* blocks the current thread indefinitely until the operation can succeed,
* and the fourth blocks for only a given maximum time limit before giving
* up. These methods are summarized in the following table:
*
* <p>
* <table BORDER CELLPADDING=3 CELLSPACING=1>
* <tr>
* <td ALIGN=CENTER COLSPAN = 5> <b>First Element (Head)</b></td>
* </tr>
* <tr>
* <td></td>
* <td ALIGN=CENTER><em>Throws exception</em></td>
* <td ALIGN=CENTER><em>Special value</em></td>
* <td ALIGN=CENTER><em>Blocks</em></td>
* <td ALIGN=CENTER><em>Times out</em></td>
* </tr>
* <tr>
* <td><b>Insert</b></td>
* <td>{@link #addFirst addFirst(e)}</td>
* <td>{@link #offerFirst offerFirst(e)}</td>
* <td>{@link #putFirst putFirst(e)}</td>
* <td>{@link #offerFirst offerFirst(e, time, unit)}</td>
* </tr>
* <tr>
* <td><b>Remove</b></td>
* <td>{@link #removeFirst removeFirst()}</td>
* <td>{@link #pollFirst pollFirst()}</td>
* <td>{@link #takeFirst takeFirst()}</td>
* <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td>
* </tr>
* <tr>
* <td><b>Examine</b></td>
* <td>{@link #getFirst getFirst()}</td>
* <td>{@link #peekFirst peekFirst()}</td>
* <td><em>not applicable</em></td>
* <td><em>not applicable</em></td>
* </tr>
* <tr>
* <td ALIGN=CENTER COLSPAN = 5> <b>Last Element (Tail)</b></td>
* </tr>
* <tr>
* <td></td>
* <td ALIGN=CENTER><em>Throws exception</em></td>
* <td ALIGN=CENTER><em>Special value</em></td>
* <td ALIGN=CENTER><em>Blocks</em></td>
* <td ALIGN=CENTER><em>Times out</em></td>
* </tr>
* <tr>
* <td><b>Insert</b></td>
* <td>{@link #addLast addLast(e)}</td>
* <td>{@link #offerLast offerLast(e)}</td>
* <td>{@link #putLast putLast(e)}</td>
* <td>{@link #offerLast offerLast(e, time, unit)}</td>
* </tr>
* <tr>
* <td><b>Remove</b></td>
* <td>{@link #removeLast() removeLast()}</td>
* <td>{@link #pollLast() pollLast()}</td>
* <td>{@link #takeLast takeLast()}</td>
* <td>{@link #pollLast(long, TimeUnit) pollLast(time, unit)}</td>
* </tr>
* <tr>
* <td><b>Examine</b></td>
* <td>{@link #getLast getLast()}</td>
* <td>{@link #peekLast peekLast()}</td>
* <td><em>not applicable</em></td>
* <td><em>not applicable</em></td>
* </tr>
* </table>
*
* <p>Like any {@link BlockingQueue}, a <tt>BlockingDeque</tt> is thread safe,
* does not permit null elements, and may (or may not) be
* capacity-constrained.
*
* <p>A <tt>BlockingDeque</tt> implementation may be used directly as a FIFO
* <tt>BlockingQueue</tt>. The methods inherited from the
* <tt>BlockingQueue</tt> interface are precisely equivalent to
* <tt>BlockingDeque</tt> methods as indicated in the following table:
*
* <p>
* <table BORDER CELLPADDING=3 CELLSPACING=1>
* <tr>
* <td ALIGN=CENTER> <b><tt>BlockingQueue</tt> Method</b></td>
* <td ALIGN=CENTER> <b>Equivalent <tt>BlockingDeque</tt> Method</b></td>
* </tr>
* <tr>
* <td ALIGN=CENTER COLSPAN = 2> <b>Insert</b></td>
* </tr>
* <tr>
* <td>{@link #add add(e)}</td>
* <td>{@link #addLast addLast(e)}</td>
* </tr>
* <tr>
* <td>{@link #offer offer(e)}</td>
* <td>{@link #offerLast offerLast(e)}</td>
* </tr>
* <tr>
* <td>{@link #put put(e)}</td>
* <td>{@link #putLast putLast(e)}</td>
* </tr>
* <tr>
* <td>{@link #offer offer(e, time, unit)}</td>
* <td>{@link #offerLast offerLast(e, time, unit)}</td>
* </tr>
* <tr>
* <td ALIGN=CENTER COLSPAN = 2> <b>Remove</b></td>
* </tr>
* <tr>
* <td>{@link #remove() remove()}</td>
* <td>{@link #removeFirst() removeFirst()}</td>
* </tr>
* <tr>
* <td>{@link #poll() poll()}</td>
* <td>{@link #pollFirst() pollFirst()}</td>
* </tr>
* <tr>
* <td>{@link #take() take()}</td>
* <td>{@link #takeFirst() takeFirst()}</td>
* </tr>
* <tr>
* <td>{@link #poll(long, TimeUnit) poll(time, unit)}</td>
* <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td>
* </tr>
* <tr>
* <td ALIGN=CENTER COLSPAN = 2> <b>Examine</b></td>
* </tr>
* <tr>
* <td>{@link #element() element()}</td>
* <td>{@link #getFirst() getFirst()}</td>
* </tr>
* <tr>
* <td>{@link #peek() peek()}</td>
* <td>{@link #peekFirst() peekFirst()}</td>
* </tr>
* </table>
*
* <p>Memory consistency effects: As with other concurrent
* collections, actions in a thread prior to placing an object into a
* {@code BlockingDeque}
* <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
* actions subsequent to the access or removal of that element from
* the {@code BlockingDeque} in another thread.
*
* <p>This interface is a member of the
* <a href="{@docRoot}/../technotes/guides/collections/index.html">
* Java Collections Framework</a>.
*
* @since 1.6
* @author Doug Lea
* @param <E> the type of elements held in this collection
*/
public interface BlockingDeque<E> extends BlockingQueue<E>, Deque<E> {
/*
* We have "diamond" multiple interface inheritance here, and that
* introduces ambiguities. Methods might end up with different
* specs depending on the branch chosen by javadoc. Thus a lot of
* methods specs here are copied from superinterfaces.
*/
/**
* Inserts the specified element at the front of this deque if it is
* possible to do so immediately without violating capacity restrictions,
* throwing an <tt>IllegalStateException</tt> if no space is currently
* available. When using a capacity-restricted deque, it is generally
* preferable to use {@link #offerFirst offerFirst}.
*
* @param e the element to add
* @throws IllegalStateException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException {@inheritDoc}
*/
void addFirst(E e);
/**
* Inserts the specified element at the end of this deque if it is
* possible to do so immediately without violating capacity restrictions,
* throwing an <tt>IllegalStateException</tt> if no space is currently
* available. When using a capacity-restricted deque, it is generally
* preferable to use {@link #offerLast offerLast}.
*
* @param e the element to add
* @throws IllegalStateException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException {@inheritDoc}
*/
void addLast(E e);
/**
* Inserts the specified element at the front of this deque if it is
* possible to do so immediately without violating capacity restrictions,
* returning <tt>true</tt> upon success and <tt>false</tt> if no space is
* currently available.
* When using a capacity-restricted deque, this method is generally
* preferable to the {@link #addFirst addFirst} method, which can
* fail to insert an element only by throwing an exception.
*
* @param e the element to add
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException {@inheritDoc}
*/
boolean offerFirst(E e);
/**
* Inserts the specified element at the end of this deque if it is
* possible to do so immediately without violating capacity restrictions,
* returning <tt>true</tt> upon success and <tt>false</tt> if no space is
* currently available.
* When using a capacity-restricted deque, this method is generally
* preferable to the {@link #addLast addLast} method, which can
* fail to insert an element only by throwing an exception.
*
* @param e the element to add
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException {@inheritDoc}
*/
boolean offerLast(E e);
/**
* Inserts the specified element at the front of this deque,
* waiting if necessary for space to become available.
*
* @param e the element to add
* @throws InterruptedException if interrupted while waiting
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void putFirst(E e) throws InterruptedException;
/**
* Inserts the specified element at the end of this deque,
* waiting if necessary for space to become available.
*
* @param e the element to add
* @throws InterruptedException if interrupted while waiting
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void putLast(E e) throws InterruptedException;
/**
* Inserts the specified element at the front of this deque,
* waiting up to the specified wait time if necessary for space to
* become available.
*
* @param e the element to add
* @param timeout how long to wait before giving up, in units of
* <tt>unit</tt>
* @param unit a <tt>TimeUnit</tt> determining how to interpret the
* <tt>timeout</tt> parameter
* @return <tt>true</tt> if successful, or <tt>false</tt> if
* the specified waiting time elapses before space is available
* @throws InterruptedException if interrupted while waiting
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offerFirst(E e, long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Inserts the specified element at the end of this deque,
* waiting up to the specified wait time if necessary for space to
* become available.
*
* @param e the element to add
* @param timeout how long to wait before giving up, in units of
* <tt>unit</tt>
* @param unit a <tt>TimeUnit</tt> determining how to interpret the
* <tt>timeout</tt> parameter
* @return <tt>true</tt> if successful, or <tt>false</tt> if
* the specified waiting time elapses before space is available
* @throws InterruptedException if interrupted while waiting
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offerLast(E e, long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Retrieves and removes the first element of this deque, waiting
* if necessary until an element becomes available.
*
* @return the head of this deque
* @throws InterruptedException if interrupted while waiting
*/
E takeFirst() throws InterruptedException;
/**
* Retrieves and removes the last element of this deque, waiting
* if necessary until an element becomes available.
*
* @return the tail of this deque
* @throws InterruptedException if interrupted while waiting
*/
E takeLast() throws InterruptedException;
/**
* Retrieves and removes the first element of this deque, waiting
* up to the specified wait time if necessary for an element to
* become available.
*
* @param timeout how long to wait before giving up, in units of
* <tt>unit</tt>
* @param unit a <tt>TimeUnit</tt> determining how to interpret the
* <tt>timeout</tt> parameter
* @return the head of this deque, or <tt>null</tt> if the specified
* waiting time elapses before an element is available
* @throws InterruptedException if interrupted while waiting
*/
E pollFirst(long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Retrieves and removes the last element of this deque, waiting
* up to the specified wait time if necessary for an element to
* become available.
*
* @param timeout how long to wait before giving up, in units of
* <tt>unit</tt>
* @param unit a <tt>TimeUnit</tt> determining how to interpret the
* <tt>timeout</tt> parameter
* @return the tail of this deque, or <tt>null</tt> if the specified
* waiting time elapses before an element is available
* @throws InterruptedException if interrupted while waiting
*/
E pollLast(long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Removes the first occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the first element <tt>e</tt> such that
* <tt>o.equals(e)</tt> (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if an element was removed as a result of this call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null (optional)
*/
boolean removeFirstOccurrence(Object o);
/**
* Removes the last occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the last element <tt>e</tt> such that
* <tt>o.equals(e)</tt> (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if an element was removed as a result of this call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null (optional)
*/
boolean removeLastOccurrence(Object o);
// *** BlockingQueue methods ***
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque) if it is possible to do so
* immediately without violating capacity restrictions, returning
* <tt>true</tt> upon success and throwing an
* <tt>IllegalStateException</tt> if no space is currently available.
* When using a capacity-restricted deque, it is generally preferable to
* use {@link #offer offer}.
*
* <p>This method is equivalent to {@link #addLast addLast}.
*
* @param e the element to add
* @throws IllegalStateException {@inheritDoc}
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean add(E e);
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque) if it is possible to do so
* immediately without violating capacity restrictions, returning
* <tt>true</tt> upon success and <tt>false</tt> if no space is currently
* available. When using a capacity-restricted deque, this method is
* generally preferable to the {@link #add} method, which can fail to
* insert an element only by throwing an exception.
*
* <p>This method is equivalent to {@link #offerLast offerLast}.
*
* @param e the element to add
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offer(E e);
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque), waiting if necessary for
* space to become available.
*
* <p>This method is equivalent to {@link #putLast putLast}.
*
* @param e the element to add
* @throws InterruptedException {@inheritDoc}
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void put(E e) throws InterruptedException;
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque), waiting up to the
* specified wait time if necessary for space to become available.
*
* <p>This method is equivalent to
* {@link #offerLast offerLast}.
*
* @param e the element to add
* @return <tt>true</tt> if the element was added to this deque, else
* <tt>false</tt>
* @throws InterruptedException {@inheritDoc}
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offer(E e, long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque).
* This method differs from {@link #poll poll} only in that it
* throws an exception if this deque is empty.
*
* <p>This method is equivalent to {@link #removeFirst() removeFirst}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
*/
E remove();
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque), or returns
* <tt>null</tt> if this deque is empty.
*
* <p>This method is equivalent to {@link #pollFirst()}.
*
* @return the head of this deque, or <tt>null</tt> if this deque is empty
*/
E poll();
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque), waiting if
* necessary until an element becomes available.
*
* <p>This method is equivalent to {@link #takeFirst() takeFirst}.
*
* @return the head of this deque
* @throws InterruptedException if interrupted while waiting
*/
E take() throws InterruptedException;
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque), waiting up to the
* specified wait time if necessary for an element to become available.
*
* <p>This method is equivalent to
* {@link #pollFirst(long,TimeUnit) pollFirst}.
*
* @return the head of this deque, or <tt>null</tt> if the
* specified waiting time elapses before an element is available
* @throws InterruptedException if interrupted while waiting
*/
E poll(long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Retrieves, but does not remove, the head of the queue represented by
* this deque (in other words, the first element of this deque).
* This method differs from {@link #peek peek} only in that it throws an
* exception if this deque is empty.
*
* <p>This method is equivalent to {@link #getFirst() getFirst}.
*
* @return the head of this deque
* @throws NoSuchElementException if this deque is empty
*/
E element();
/**
* Retrieves, but does not remove, the head of the queue represented by
* this deque (in other words, the first element of this deque), or
* returns <tt>null</tt> if this deque is empty.
*
* <p>This method is equivalent to {@link #peekFirst() peekFirst}.
*
* @return the head of this deque, or <tt>null</tt> if this deque is empty
*/
E peek();
/**
* Removes the first occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the first element <tt>e</tt> such that
* <tt>o.equals(e)</tt> (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* <p>This method is equivalent to
* {@link #removeFirstOccurrence removeFirstOccurrence}.
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if this deque changed as a result of the call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null (optional)
*/
boolean remove(Object o);
/**
* Returns <tt>true</tt> if this deque contains the specified element.
* More formally, returns <tt>true</tt> if and only if this deque contains
* at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>.
*
* @param o object to be checked for containment in this deque
* @return <tt>true</tt> if this deque contains the specified element
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null (optional)
*/
public boolean contains(Object o);
/**
* Returns the number of elements in this deque.
*
* @return the number of elements in this deque
*/
public int size();
/**
* Returns an iterator over the elements in this deque in proper sequence.
* The elements will be returned in order from first (head) to last (tail).
*
* @return an iterator over the elements in this deque in proper sequence
*/
Iterator<E> iterator();
// *** Stack methods ***
/**
* Pushes an element onto the stack represented by this deque. In other
* words, inserts the element at the front of this deque unless it would
* violate capacity restrictions.
*
* <p>This method is equivalent to {@link #addFirst addFirst}.
*
* @throws IllegalStateException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException {@inheritDoc}
*/
void push(E e);
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/deque/Deque.java 0 → 100644
/*
* Written by Doug Lea and Josh Bloch with assistance from members of
* JCP JSR-166 Expert Group and released to the public domain, as explained
* at http://creativecommons.org/licenses/publicdomain
*/
package com.nostra13.universalimageloader.core.assist.deque;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.Stack;
/**
* A linear collection that supports element insertion and removal at
* both ends. The name <i>deque</i> is short for "double ended queue"
* and is usually pronounced "deck". Most <tt>Deque</tt>
* implementations place no fixed limits on the number of elements
* they may contain, but this interface supports capacity-restricted
* deques as well as those with no fixed size limit.
*
* <p>This interface defines methods to access the elements at both
* ends of the deque. Methods are provided to insert, remove, and
* examine the element. Each of these methods exists in two forms:
* one throws an exception if the operation fails, the other returns a
* special value (either <tt>null</tt> or <tt>false</tt>, depending on
* the operation). The latter form of the insert operation is
* designed specifically for use with capacity-restricted
* <tt>Deque</tt> implementations; in most implementations, insert
* operations cannot fail.
*
* <p>The twelve methods described above are summarized in the
* following table:
*
* <p>
* <table BORDER CELLPADDING=3 CELLSPACING=1>
* <tr>
* <td></td>
* <td ALIGN=CENTER COLSPAN = 2> <b>First Element (Head)</b></td>
* <td ALIGN=CENTER COLSPAN = 2> <b>Last Element (Tail)</b></td>
* </tr>
* <tr>
* <td></td>
* <td ALIGN=CENTER><em>Throws exception</em></td>
* <td ALIGN=CENTER><em>Special value</em></td>
* <td ALIGN=CENTER><em>Throws exception</em></td>
* <td ALIGN=CENTER><em>Special value</em></td>
* </tr>
* <tr>
* <td><b>Insert</b></td>
* <td>{@link #addFirst addFirst(e)}</td>
* <td>{@link #offerFirst offerFirst(e)}</td>
* <td>{@link #addLast addLast(e)}</td>
* <td>{@link #offerLast offerLast(e)}</td>
* </tr>
* <tr>
* <td><b>Remove</b></td>
* <td>{@link #removeFirst removeFirst()}</td>
* <td>{@link #pollFirst pollFirst()}</td>
* <td>{@link #removeLast removeLast()}</td>
* <td>{@link #pollLast pollLast()}</td>
* </tr>
* <tr>
* <td><b>Examine</b></td>
* <td>{@link #getFirst getFirst()}</td>
* <td>{@link #peekFirst peekFirst()}</td>
* <td>{@link #getLast getLast()}</td>
* <td>{@link #peekLast peekLast()}</td>
* </tr>
* </table>
*
* <p>This interface extends the {@link Queue} interface. When a deque is
* used as a queue, FIFO (First-In-First-Out) behavior results. Elements are
* added at the end of the deque and removed from the beginning. The methods
* inherited from the <tt>Queue</tt> interface are precisely equivalent to
* <tt>Deque</tt> methods as indicated in the following table:
*
* <p>
* <table BORDER CELLPADDING=3 CELLSPACING=1>
* <tr>
* <td ALIGN=CENTER> <b><tt>Queue</tt> Method</b></td>
* <td ALIGN=CENTER> <b>Equivalent <tt>Deque</tt> Method</b></td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#add add(e)}</td>
* <td>{@link #addLast addLast(e)}</td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#offer offer(e)}</td>
* <td>{@link #offerLast offerLast(e)}</td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#remove remove()}</td>
* <td>{@link #removeFirst removeFirst()}</td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#poll poll()}</td>
* <td>{@link #pollFirst pollFirst()}</td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#element element()}</td>
* <td>{@link #getFirst getFirst()}</td>
* </tr>
* <tr>
* <td>{@link java.util.Queue#peek peek()}</td>
* <td>{@link #peek peekFirst()}</td>
* </tr>
* </table>
*
* <p>Deques can also be used as LIFO (Last-In-First-Out) stacks. This
* interface should be used in preference to the legacy {@link Stack} class.
* When a deque is used as a stack, elements are pushed and popped from the
* beginning of the deque. Stack methods are precisely equivalent to
* <tt>Deque</tt> methods as indicated in the table below:
*
* <p>
* <table BORDER CELLPADDING=3 CELLSPACING=1>
* <tr>
* <td ALIGN=CENTER> <b>Stack Method</b></td>
* <td ALIGN=CENTER> <b>Equivalent <tt>Deque</tt> Method</b></td>
* </tr>
* <tr>
* <td>{@link #push push(e)}</td>
* <td>{@link #addFirst addFirst(e)}</td>
* </tr>
* <tr>
* <td>{@link #pop pop()}</td>
* <td>{@link #removeFirst removeFirst()}</td>
* </tr>
* <tr>
* <td>{@link #peek peek()}</td>
* <td>{@link #peekFirst peekFirst()}</td>
* </tr>
* </table>
*
* <p>Note that the {@link #peek peek} method works equally well when
* a deque is used as a queue or a stack; in either case, elements are
* drawn from the beginning of the deque.
*
* <p>This interface provides two methods to remove interior
* elements, {@link #removeFirstOccurrence removeFirstOccurrence} and
* {@link #removeLastOccurrence removeLastOccurrence}.
*
* <p>Unlike the {@link List} interface, this interface does not
* provide support for indexed access to elements.
*
* <p>While <tt>Deque</tt> implementations are not strictly required
* to prohibit the insertion of null elements, they are strongly
* encouraged to do so. Users of any <tt>Deque</tt> implementations
* that do allow null elements are strongly encouraged <i>not</i> to
* take advantage of the ability to insert nulls. This is so because
* <tt>null</tt> is used as a special return value by various methods
* to indicated that the deque is empty.
*
* <p><tt>Deque</tt> implementations generally do not define
* element-based versions of the <tt>equals</tt> and <tt>hashCode</tt>
* methods, but instead inherit the identity-based versions from class
* <tt>Object</tt>.
*
* @author Doug Lea
* @author Josh Bloch
* @since 1.6
* @param <E> the type of elements held in this collection
*/
public interface Deque<E> extends Queue<E> {
/**
* Inserts the specified element at the front of this deque if it is
* possible to do so immediately without violating capacity restrictions.
* When using a capacity-restricted deque, it is generally preferable to
* use method {@link #offerFirst}.
*
* @param e the element to add
* @throws IllegalStateException if the element cannot be added at this
* time due to capacity restrictions
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void addFirst(E e);
/**
* Inserts the specified element at the end of this deque if it is
* possible to do so immediately without violating capacity restrictions.
* When using a capacity-restricted deque, it is generally preferable to
* use method {@link #offerLast}.
*
* <p>This method is equivalent to {@link #add}.
*
* @param e the element to add
* @throws IllegalStateException if the element cannot be added at this
* time due to capacity restrictions
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void addLast(E e);
/**
* Inserts the specified element at the front of this deque unless it would
* violate capacity restrictions. When using a capacity-restricted deque,
* this method is generally preferable to the {@link #addFirst} method,
* which can fail to insert an element only by throwing an exception.
*
* @param e the element to add
* @return <tt>true</tt> if the element was added to this deque, else
* <tt>false</tt>
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offerFirst(E e);
/**
* Inserts the specified element at the end of this deque unless it would
* violate capacity restrictions. When using a capacity-restricted deque,
* this method is generally preferable to the {@link #addLast} method,
* which can fail to insert an element only by throwing an exception.
*
* @param e the element to add
* @return <tt>true</tt> if the element was added to this deque, else
* <tt>false</tt>
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offerLast(E e);
/**
* Retrieves and removes the first element of this deque. This method
* differs from {@link #pollFirst pollFirst} only in that it throws an
* exception if this deque is empty.
*
* @return the head of this deque
* @throws NoSuchElementException if this deque is empty
*/
E removeFirst();
/**
* Retrieves and removes the last element of this deque. This method
* differs from {@link #pollLast pollLast} only in that it throws an
* exception if this deque is empty.
*
* @return the tail of this deque
* @throws NoSuchElementException if this deque is empty
*/
E removeLast();
/**
* Retrieves and removes the first element of this deque,
* or returns <tt>null</tt> if this deque is empty.
*
* @return the head of this deque, or <tt>null</tt> if this deque is empty
*/
E pollFirst();
/**
* Retrieves and removes the last element of this deque,
* or returns <tt>null</tt> if this deque is empty.
*
* @return the tail of this deque, or <tt>null</tt> if this deque is empty
*/
E pollLast();
/**
* Retrieves, but does not remove, the first element of this deque.
*
* This method differs from {@link #peekFirst peekFirst} only in that it
* throws an exception if this deque is empty.
*
* @return the head of this deque
* @throws NoSuchElementException if this deque is empty
*/
E getFirst();
/**
* Retrieves, but does not remove, the last element of this deque.
* This method differs from {@link #peekLast peekLast} only in that it
* throws an exception if this deque is empty.
*
* @return the tail of this deque
* @throws NoSuchElementException if this deque is empty
*/
E getLast();
/**
* Retrieves, but does not remove, the first element of this deque,
* or returns <tt>null</tt> if this deque is empty.
*
* @return the head of this deque, or <tt>null</tt> if this deque is empty
*/
E peekFirst();
/**
* Retrieves, but does not remove, the last element of this deque,
* or returns <tt>null</tt> if this deque is empty.
*
* @return the tail of this deque, or <tt>null</tt> if this deque is empty
*/
E peekLast();
/**
* Removes the first occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the first element <tt>e</tt> such that
* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>
* (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if an element was removed as a result of this call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements (optional)
*/
boolean removeFirstOccurrence(Object o);
/**
* Removes the last occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the last element <tt>e</tt> such that
* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>
* (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if an element was removed as a result of this call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements (optional)
*/
boolean removeLastOccurrence(Object o);
// *** Queue methods ***
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque) if it is possible to do so
* immediately without violating capacity restrictions, returning
* <tt>true</tt> upon success and throwing an
* <tt>IllegalStateException</tt> if no space is currently available.
* When using a capacity-restricted deque, it is generally preferable to
* use {@link #offer offer}.
*
* <p>This method is equivalent to {@link #addLast}.
*
* @param e the element to add
* @return <tt>true</tt> (as specified by {@link Collection#add})
* @throws IllegalStateException if the element cannot be added at this
* time due to capacity restrictions
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean add(E e);
/**
* Inserts the specified element into the queue represented by this deque
* (in other words, at the tail of this deque) if it is possible to do so
* immediately without violating capacity restrictions, returning
* <tt>true</tt> upon success and <tt>false</tt> if no space is currently
* available. When using a capacity-restricted deque, this method is
* generally preferable to the {@link #add} method, which can fail to
* insert an element only by throwing an exception.
*
* <p>This method is equivalent to {@link #offerLast}.
*
* @param e the element to add
* @return <tt>true</tt> if the element was added to this deque, else
* <tt>false</tt>
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
boolean offer(E e);
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque).
* This method differs from {@link #poll poll} only in that it throws an
* exception if this deque is empty.
*
* <p>This method is equivalent to {@link #removeFirst()}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
*/
E remove();
/**
* Retrieves and removes the head of the queue represented by this deque
* (in other words, the first element of this deque), or returns
* <tt>null</tt> if this deque is empty.
*
* <p>This method is equivalent to {@link #pollFirst()}.
*
* @return the first element of this deque, or <tt>null</tt> if
* this deque is empty
*/
E poll();
/**
* Retrieves, but does not remove, the head of the queue represented by
* this deque (in other words, the first element of this deque).
* This method differs from {@link #peek peek} only in that it throws an
* exception if this deque is empty.
*
* <p>This method is equivalent to {@link #getFirst()}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
*/
E element();
/**
* Retrieves, but does not remove, the head of the queue represented by
* this deque (in other words, the first element of this deque), or
* returns <tt>null</tt> if this deque is empty.
*
* <p>This method is equivalent to {@link #peekFirst()}.
*
* @return the head of the queue represented by this deque, or
* <tt>null</tt> if this deque is empty
*/
E peek();
// *** Stack methods ***
/**
* Pushes an element onto the stack represented by this deque (in other
* words, at the head of this deque) if it is possible to do so
* immediately without violating capacity restrictions, returning
* <tt>true</tt> upon success and throwing an
* <tt>IllegalStateException</tt> if no space is currently available.
*
* <p>This method is equivalent to {@link #addFirst}.
*
* @param e the element to push
* @throws IllegalStateException if the element cannot be added at this
* time due to capacity restrictions
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this deque
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this deque
*/
void push(E e);
/**
* Pops an element from the stack represented by this deque. In other
* words, removes and returns the first element of this deque.
*
* <p>This method is equivalent to {@link #removeFirst()}.
*
* @return the element at the front of this deque (which is the top
* of the stack represented by this deque)
* @throws NoSuchElementException if this deque is empty
*/
E pop();
// *** Collection methods ***
/**
* Removes the first occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the first element <tt>e</tt> such that
* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>
* (if such an element exists).
* Returns <tt>true</tt> if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* <p>This method is equivalent to {@link #removeFirstOccurrence}.
*
* @param o element to be removed from this deque, if present
* @return <tt>true</tt> if an element was removed as a result of this call
* @throws ClassCastException if the class of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements (optional)
*/
boolean remove(Object o);
/**
* Returns <tt>true</tt> if this deque contains the specified element.
* More formally, returns <tt>true</tt> if and only if this deque contains
* at least one element <tt>e</tt> such that
* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
*
* @param o element whose presence in this deque is to be tested
* @return <tt>true</tt> if this deque contains the specified element
* @throws ClassCastException if the type of the specified element
* is incompatible with this deque (optional)
* @throws NullPointerException if the specified element is null and this
* deque does not permit null elements (optional)
*/
boolean contains(Object o);
/**
* Returns the number of elements in this deque.
*
* @return the number of elements in this deque
*/
public int size();
/**
* Returns an iterator over the elements in this deque in proper sequence.
* The elements will be returned in order from first (head) to last (tail).
*
* @return an iterator over the elements in this deque in proper sequence
*/
Iterator<E> iterator();
/**
* Returns an iterator over the elements in this deque in reverse
* sequential order. The elements will be returned in order from
* last (tail) to first (head).
*
* @return an iterator over the elements in this deque in reverse
* sequence
*/
Iterator<E> descendingIterator();
}
imageLoader/src/com/nostra13/universalimageloader/core/assist/deque/LIFOLinkedBlockingDeque.java 0 → 100644
package com.nostra13.universalimageloader.core.assist.deque;
import java.util.NoSuchElementException;
/**
* {@link LinkedBlockingDeque} using LIFO algorithm
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @since 1.6.3
*/
public class LIFOLinkedBlockingDeque<T> extends LinkedBlockingDeque<T> {
private static final long serialVersionUID = -4114786347960826192L;
/**
* Inserts the specified element at the front of this deque if it is possible to do so immediately without violating
* capacity restrictions, returning <tt>true</tt> upon success and <tt>false</tt> if no space is currently
* available. When using a capacity-restricted deque, this method is generally preferable to the {@link #addFirst
* addFirst} method, which can fail to insert an element only by throwing an exception.
*
* @param e
* the element to add
* @throws ClassCastException
* {@inheritDoc}
* @throws NullPointerException
* if the specified element is null
* @throws IllegalArgumentException
* {@inheritDoc}
*/
@Override
public boolean offer(T e) {
return super.offerFirst(e);
}
/**
* Retrieves and removes the first element of this deque. This method differs from {@link #pollFirst pollFirst} only
* in that it throws an exception if this deque is empty.
*
* @return the head of this deque
* @throws NoSuchElementException
* if this deque is empty
*/
@Override
public T remove() {
return super.removeFirst();
}
}
\ No newline at end of file
imageLoader/src/com/nostra13/universalimageloader/core/assist/deque/LinkedBlockingDeque.java 0 → 100644
/*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/licenses/publicdomain
*/
package com.nostra13.universalimageloader.core.assist.deque;
import java.util.AbstractQueue;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
/**
* An optionally-bounded {@linkplain BlockingDeque blocking deque} based on
* linked nodes.
*
* <p> The optional capacity bound constructor argument serves as a
* way to prevent excessive expansion. The capacity, if unspecified,
* is equal to {@link Integer#MAX_VALUE}. Linked nodes are
* dynamically created upon each insertion unless this would bring the
* deque above capacity.
*
* <p>Most operations run in constant time (ignoring time spent
* blocking). Exceptions include {@link #remove(Object) remove},
* {@link #removeFirstOccurrence removeFirstOccurrence}, {@link
* #removeLastOccurrence removeLastOccurrence}, {@link #contains
* contains}, {@link #iterator iterator.remove()}, and the bulk
* operations, all of which run in linear time.
*
* <p>This class and its iterator implement all of the
* <em>optional</em> methods of the {@link Collection} and {@link
* Iterator} interfaces.
*
* <p>This class is a member of the
* <a href="{@docRoot}/../technotes/guides/collections/index.html">
* Java Collections Framework</a>.
*
* @since 1.6
* @author Doug Lea
* @param <E> the type of elements held in this collection
*/
public class LinkedBlockingDeque<E>
extends AbstractQueue<E>
implements BlockingDeque<E>, java.io.Serializable {
/*
* Implemented as a simple doubly-linked list protected by a
* single lock and using conditions to manage blocking.
*
* To implement weakly consistent iterators, it appears we need to
* keep all Nodes GC-reachable from a predecessor dequeued Node.
* That would cause two problems:
* - allow a rogue Iterator to cause unbounded memory retention
* - cause cross-generational linking of old Nodes to new Nodes if
* a Node was tenured while live, which generational GCs have a
* hard time dealing with, causing repeated major collections.
* However, only non-deleted Nodes need to be reachable from
* dequeued Nodes, and reachability does not necessarily have to
* be of the kind understood by the GC. We use the trick of
* linking a Node that has just been dequeued to itself. Such a
* self-link implicitly means to jump to "first" (for next links)
* or "last" (for prev links).
*/
/*
* We have "diamond" multiple interface/abstract class inheritance
* here, and that introduces ambiguities. Often we want the
* BlockingDeque javadoc combined with the AbstractQueue
* implementation, so a lot of method specs are duplicated here.
*/
private static final long serialVersionUID = -387911632671998426L;
/** Doubly-linked list node class */
static final class Node<E> {
/**
* The item, or null if this node has been removed.
*/
E item;
/**
* One of:
* - the real predecessor Node
* - this Node, meaning the predecessor is tail
* - null, meaning there is no predecessor
*/
Node<E> prev;
/**
* One of:
* - the real successor Node
* - this Node, meaning the successor is head
* - null, meaning there is no successor
*/
Node<E> next;
Node(E x) {
item = x;
}
}
/**
* Pointer to first node.
* Invariant: (first == null && last == null) ||
* (first.prev == null && first.item != null)
*/
transient Node<E> first;
/**
* Pointer to last node.
* Invariant: (first == null && last == null) ||
* (last.next == null && last.item != null)
*/
transient Node<E> last;
/** Number of items in the deque */
private transient int count;
/** Maximum number of items in the deque */
private final int capacity;
/** Main lock guarding all access */
final ReentrantLock lock = new ReentrantLock();
/** Condition for waiting takes */
private final Condition notEmpty = lock.newCondition();
/** Condition for waiting puts */
private final Condition notFull = lock.newCondition();
/**
* Creates a {@code LinkedBlockingDeque} with a capacity of
* {@link Integer#MAX_VALUE}.
*/
public LinkedBlockingDeque() {
this(Integer.MAX_VALUE);
}
/**
* Creates a {@code LinkedBlockingDeque} with the given (fixed) capacity.
*
* @param capacity the capacity of this deque
* @throws IllegalArgumentException if {@code capacity} is less than 1
*/
public LinkedBlockingDeque(int capacity) {
if (capacity <= 0) throw new IllegalArgumentException();
this.capacity = capacity;
}
/**
* Creates a {@code LinkedBlockingDeque} with a capacity of
* {@link Integer#MAX_VALUE}, initially containing the elements of
* the given collection, added in traversal order of the
* collection's iterator.
*
* @param c the collection of elements to initially contain
* @throws NullPointerException if the specified collection or any
* of its elements are null
*/
public LinkedBlockingDeque(Collection<? extends E> c) {
this(Integer.MAX_VALUE);
final ReentrantLock lock = this.lock;
lock.lock(); // Never contended, but necessary for visibility
try {
for (E e : c) {
if (e == null)
throw new NullPointerException();
if (!linkLast(new Node<E>(e)))
throw new IllegalStateException("Deque full");
}
} finally {
lock.unlock();
}
}
// Basic linking and unlinking operations, called only while holding lock
/**
* Links node as first element, or returns false if full.
*/
private boolean linkFirst(Node<E> node) {
// assert lock.isHeldByCurrentThread();
if (count >= capacity)
return false;
Node<E> f = first;
node.next = f;
first = node;
if (last == null)
last = node;
else
f.prev = node;
++count;
notEmpty.signal();
return true;
}
/**
* Links node as last element, or returns false if full.
*/
private boolean linkLast(Node<E> node) {
// assert lock.isHeldByCurrentThread();
if (count >= capacity)
return false;
Node<E> l = last;
node.prev = l;
last = node;
if (first == null)
first = node;
else
l.next = node;
++count;
notEmpty.signal();
return true;
}
/**
* Removes and returns first element, or null if empty.
*/
private E unlinkFirst() {
// assert lock.isHeldByCurrentThread();
Node<E> f = first;
if (f == null)
return null;
Node<E> n = f.next;
E item = f.item;
f.item = null;
f.next = f; // help GC
first = n;
if (n == null)
last = null;
else
n.prev = null;
--count;
notFull.signal();
return item;
}
/**
* Removes and returns last element, or null if empty.
*/
private E unlinkLast() {
// assert lock.isHeldByCurrentThread();
Node<E> l = last;
if (l == null)
return null;
Node<E> p = l.prev;
E item = l.item;
l.item = null;
l.prev = l; // help GC
last = p;
if (p == null)
first = null;
else
p.next = null;
--count;
notFull.signal();
return item;
}
/**
* Unlinks x.
*/
void unlink(Node<E> x) {
// assert lock.isHeldByCurrentThread();
Node<E> p = x.prev;
Node<E> n = x.next;
if (p == null) {
unlinkFirst();
} else if (n == null) {
unlinkLast();
} else {
p.next = n;
n.prev = p;
x.item = null;
// Don't mess with x's links. They may still be in use by
// an iterator.
--count;
notFull.signal();
}
}
// BlockingDeque methods
/**
* @throws IllegalStateException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public void addFirst(E e) {
if (!offerFirst(e))
throw new IllegalStateException("Deque full");
}
/**
* @throws IllegalStateException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public void addLast(E e) {
if (!offerLast(e))
throw new IllegalStateException("Deque full");
}
/**
* @throws NullPointerException {@inheritDoc}
*/
public boolean offerFirst(E e) {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
final ReentrantLock lock = this.lock;
lock.lock();
try {
return linkFirst(node);
} finally {
lock.unlock();
}
}
/**
* @throws NullPointerException {@inheritDoc}
*/
public boolean offerLast(E e) {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
final ReentrantLock lock = this.lock;
lock.lock();
try {
return linkLast(node);
} finally {
lock.unlock();
}
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public void putFirst(E e) throws InterruptedException {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
final ReentrantLock lock = this.lock;
lock.lock();
try {
while (!linkFirst(node))
notFull.await();
} finally {
lock.unlock();
}
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public void putLast(E e) throws InterruptedException {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
final ReentrantLock lock = this.lock;
lock.lock();
try {
while (!linkLast(node))
notFull.await();
} finally {
lock.unlock();
}
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public boolean offerFirst(E e, long timeout, TimeUnit unit)
throws InterruptedException {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
long nanos = unit.toNanos(timeout);
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
while (!linkFirst(node)) {
if (nanos <= 0)
return false;
nanos = notFull.awaitNanos(nanos);
}
return true;
} finally {
lock.unlock();
}
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public boolean offerLast(E e, long timeout, TimeUnit unit)
throws InterruptedException {
if (e == null) throw new NullPointerException();
Node<E> node = new Node<E>(e);
long nanos = unit.toNanos(timeout);
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
while (!linkLast(node)) {
if (nanos <= 0)
return false;
nanos = notFull.awaitNanos(nanos);
}
return true;
} finally {
lock.unlock();
}
}
/**
* @throws NoSuchElementException {@inheritDoc}
*/
public E removeFirst() {
E x = pollFirst();
if (x == null) throw new NoSuchElementException();
return x;
}
/**
* @throws NoSuchElementException {@inheritDoc}
*/
public E removeLast() {
E x = pollLast();
if (x == null) throw new NoSuchElementException();
return x;
}
public E pollFirst() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return unlinkFirst();
} finally {
lock.unlock();
}
}
public E pollLast() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return unlinkLast();
} finally {
lock.unlock();
}
}
public E takeFirst() throws InterruptedException {
final ReentrantLock lock = this.lock;
lock.lock();
try {
E x;
while ( (x = unlinkFirst()) == null)
notEmpty.await();
return x;
} finally {
lock.unlock();
}
}
public E takeLast() throws InterruptedException {
final ReentrantLock lock = this.lock;
lock.lock();
try {
E x;
while ( (x = unlinkLast()) == null)
notEmpty.await();
return x;
} finally {
lock.unlock();
}
}
public E pollFirst(long timeout, TimeUnit unit)
throws InterruptedException {
long nanos = unit.toNanos(timeout);
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
E x;
while ( (x = unlinkFirst()) == null) {
if (nanos <= 0)
return null;
nanos = notEmpty.awaitNanos(nanos);
}
return x;
} finally {
lock.unlock();
}
}
public E pollLast(long timeout, TimeUnit unit)
throws InterruptedException {
long nanos = unit.toNanos(timeout);
final ReentrantLock lock = this.lock;
lock.lockInterruptibly();
try {
E x;
while ( (x = unlinkLast()) == null) {
if (nanos <= 0)
return null;
nanos = notEmpty.awaitNanos(nanos);
}
return x;
} finally {
lock.unlock();
}
}
/**
* @throws NoSuchElementException {@inheritDoc}
*/
public E getFirst() {
E x = peekFirst();
if (x == null) throw new NoSuchElementException();
return x;
}
/**
* @throws NoSuchElementException {@inheritDoc}
*/
public E getLast() {
E x = peekLast();
if (x == null) throw new NoSuchElementException();
return x;
}
public E peekFirst() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return (first == null) ? null : first.item;
} finally {
lock.unlock();
}
}
public E peekLast() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return (last == null) ? null : last.item;
} finally {
lock.unlock();
}
}
public boolean removeFirstOccurrence(Object o) {
if (o == null) return false;
final ReentrantLock lock = this.lock;
lock.lock();
try {
for (Node<E> p = first; p != null; p = p.next) {
if (o.equals(p.item)) {
unlink(p);
return true;
}
}
return false;
} finally {
lock.unlock();
}
}
public boolean removeLastOccurrence(Object o) {
if (o == null) return false;
final ReentrantLock lock = this.lock;
lock.lock();
try {
for (Node<E> p = last; p != null; p = p.prev) {
if (o.equals(p.item)) {
unlink(p);
return true;
}
}
return false;
} finally {
lock.unlock();
}
}
// BlockingQueue methods
/**
* Inserts the specified element at the end of this deque unless it would
* violate capacity restrictions. When using a capacity-restricted deque,
* it is generally preferable to use method {@link #offer offer}.
*
* <p>This method is equivalent to {@link #addLast}.
*
* @throws IllegalStateException if the element cannot be added at this
* time due to capacity restrictions
* @throws NullPointerException if the specified element is null
*/
public boolean add(E e) {
addLast(e);
return true;
}
/**
* @throws NullPointerException if the specified element is null
*/
public boolean offer(E e) {
return offerLast(e);
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public void put(E e) throws InterruptedException {
putLast(e);
}
/**
* @throws NullPointerException {@inheritDoc}
* @throws InterruptedException {@inheritDoc}
*/
public boolean offer(E e, long timeout, TimeUnit unit)
throws InterruptedException {
return offerLast(e, timeout, unit);
}
/**
* Retrieves and removes the head of the queue represented by this deque.
* This method differs from {@link #poll poll} only in that it throws an
* exception if this deque is empty.
*
* <p>This method is equivalent to {@link #removeFirst() removeFirst}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
*/
public E remove() {
return removeFirst();
}
public E poll() {
return pollFirst();
}
public E take() throws InterruptedException {
return takeFirst();
}
public E poll(long timeout, TimeUnit unit) throws InterruptedException {
return pollFirst(timeout, unit);
}
/**
* Retrieves, but does not remove, the head of the queue represented by
* this deque. This method differs from {@link #peek peek} only in that
* it throws an exception if this deque is empty.
*
* <p>This method is equivalent to {@link #getFirst() getFirst}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
*/
public E element() {
return getFirst();
}
public E peek() {
return peekFirst();
}
/**
* Returns the number of additional elements that this deque can ideally
* (in the absence of memory or resource constraints) accept without
* blocking. This is always equal to the initial capacity of this deque
* less the current {@code size} of this deque.
*
* <p>Note that you <em>cannot</em> always tell if an attempt to insert
* an element will succeed by inspecting {@code remainingCapacity}
* because it may be the case that another thread is about to
* insert or remove an element.
*/
public int remainingCapacity() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return capacity - count;
} finally {
lock.unlock();
}
}
/**
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
*/
public int drainTo(Collection<? super E> c) {
return drainTo(c, Integer.MAX_VALUE);
}
/**
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
*/
public int drainTo(Collection<? super E> c, int maxElements) {
if (c == null)
throw new NullPointerException();
if (c == this)
throw new IllegalArgumentException();
final ReentrantLock lock = this.lock;
lock.lock();
try {
int n = Math.min(maxElements, count);
for (int i = 0; i < n; i++) {
c.add(first.item); // In this order, in case add() throws.
unlinkFirst();
}
return n;
} finally {
lock.unlock();
}
}
// Stack methods
/**
* @throws IllegalStateException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public void push(E e) {
addFirst(e);
}
/**
* @throws NoSuchElementException {@inheritDoc}
*/
public E pop() {
return removeFirst();
}
// Collection methods
/**
* Removes the first occurrence of the specified element from this deque.
* If the deque does not contain the element, it is unchanged.
* More formally, removes the first element {@code e} such that
* {@code o.equals(e)} (if such an element exists).
* Returns {@code true} if this deque contained the specified element
* (or equivalently, if this deque changed as a result of the call).
*
* <p>This method is equivalent to
* {@link #removeFirstOccurrence(Object) removeFirstOccurrence}.
*
* @param o element to be removed from this deque, if present
* @return {@code true} if this deque changed as a result of the call
*/
public boolean remove(Object o) {
return removeFirstOccurrence(o);
}
/**
* Returns the number of elements in this deque.
*
* @return the number of elements in this deque
*/
public int size() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
return count;
} finally {
lock.unlock();
}
}
/**
* Returns {@code true} if this deque contains the specified element.
* More formally, returns {@code true} if and only if this deque contains
* at least one element {@code e} such that {@code o.equals(e)}.
*
* @param o object to be checked for containment in this deque
* @return {@code true} if this deque contains the specified element
*/
public boolean contains(Object o) {
if (o == null) return false;
final ReentrantLock lock = this.lock;
lock.lock();
try {
for (Node<E> p = first; p != null; p = p.next)
if (o.equals(p.item))
return true;
return false;
} finally {
lock.unlock();
}
}
/*
* TODO: Add support for more efficient bulk operations.
*
* We don't want to acquire the lock for every iteration, but we
* also want other threads a chance to interact with the
* collection, especially when count is close to capacity.
*/
// /**
// * Adds all of the elements in the specified collection to this
// * queue. Attempts to addAll of a queue to itself result in
// * {@code IllegalArgumentException}. Further, the behavior of
// * this operation is undefined if the specified collection is
// * modified while the operation is in progress.
// *
// * @param c collection containing elements to be added to this queue
// * @return {@code true} if this queue changed as a result of the call
// * @throws ClassCastException {@inheritDoc}
// * @throws NullPointerException {@inheritDoc}
// * @throws IllegalArgumentException {@inheritDoc}
// * @throws IllegalStateException {@inheritDoc}
// * @see #add(Object)
// */
// public boolean addAll(Collection<? extends E> c) {
// if (c == null)
// throw new NullPointerException();
// if (c == this)
// throw new IllegalArgumentException();
// final ReentrantLock lock = this.lock;
// lock.lock();
// try {
// boolean modified = false;
// for (E e : c)
// if (linkLast(e))
// modified = true;
// return modified;
// } finally {
// lock.unlock();
// }
// }
/**
* Returns an array containing all of the elements in this deque, in
* proper sequence (from first to last element).
*
* <p>The returned array will be "safe" in that no references to it are
* maintained by this deque. (In other words, this method must allocate
* a new array). The caller is thus free to modify the returned array.
*
* <p>This method acts as bridge between array-based and collection-based
* APIs.
*
* @return an array containing all of the elements in this deque
*/
public Object[] toArray() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
Object[] a = new Object[count];
int k = 0;
for (Node<E> p = first; p != null; p = p.next)
a[k++] = p.item;
return a;
} finally {
lock.unlock();
}
}
/**
* Returns an array containing all of the elements in this deque, in
* proper sequence; the runtime type of the returned array is that of
* the specified array. If the deque fits in the specified array, it
* is returned therein. Otherwise, a new array is allocated with the
* runtime type of the specified array and the size of this deque.
*
* <p>If this deque fits in the specified array with room to spare
* (i.e., the array has more elements than this deque), the element in
* the array immediately following the end of the deque is set to
* {@code null}.
*
* <p>Like the {@link #toArray()} method, this method acts as bridge between
* array-based and collection-based APIs. Further, this method allows
* precise control over the runtime type of the output array, and may,
* under certain circumstances, be used to save allocation costs.
*
* <p>Suppose {@code x} is a deque known to contain only strings.
* The following code can be used to dump the deque into a newly
* allocated array of {@code String}:
*
* <pre>
* String[] y = x.toArray(new String[0]);</pre>
*
* Note that {@code toArray(new Object[0])} is identical in function to
* {@code toArray()}.
*
* @param a the array into which the elements of the deque are to
* be stored, if it is big enough; otherwise, a new array of the
* same runtime type is allocated for this purpose
* @return an array containing all of the elements in this deque
* @throws ArrayStoreException if the runtime type of the specified array
* is not a supertype of the runtime type of every element in
* this deque
* @throws NullPointerException if the specified array is null
*/
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
final ReentrantLock lock = this.lock;
lock.lock();
try {
if (a.length < count)
a = (T[])java.lang.reflect.Array.newInstance
(a.getClass().getComponentType(), count);
int k = 0;
for (Node<E> p = first; p != null; p = p.next)
a[k++] = (T)p.item;
if (a.length > k)
a[k] = null;
return a;
} finally {
lock.unlock();
}
}
public String toString() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
Node<E> p = first;
if (p == null)
return "[]";
StringBuilder sb = new StringBuilder();
sb.append('[');
for (;;) {
E e = p.item;
sb.append(e == this ? "(this Collection)" : e);
p = p.next;
if (p == null)
return sb.append(']').toString();
sb.append(',').append(' ');
}
} finally {
lock.unlock();
}
}
/**
* Atomically removes all of the elements from this deque.
* The deque will be empty after this call returns.
*/
public void clear() {
final ReentrantLock lock = this.lock;
lock.lock();
try {
for (Node<E> f = first; f != null; ) {
f.item = null;
Node<E> n = f.next;
f.prev = null;
f.next = null;
f = n;
}
first = last = null;
count = 0;
notFull.signalAll();
} finally {
lock.unlock();
}
}
/**
* Returns an iterator over the elements in this deque in proper sequence.
* The elements will be returned in order from first (head) to last (tail).
*
* <p>The returned iterator is a "weakly consistent" iterator that
* will never throw {@link java.util.ConcurrentModificationException
* ConcurrentModificationException}, and guarantees to traverse
* elements as they existed upon construction of the iterator, and
* may (but is not guaranteed to) reflect any modifications
* subsequent to construction.
*
* @return an iterator over the elements in this deque in proper sequence
*/
public Iterator<E> iterator() {
return new Itr();
}
/**
* Returns an iterator over the elements in this deque in reverse
* sequential order. The elements will be returned in order from
* last (tail) to first (head).
*
* <p>The returned iterator is a "weakly consistent" iterator that
* will never throw {@link java.util.ConcurrentModificationException
* ConcurrentModificationException}, and guarantees to traverse
* elements as they existed upon construction of the iterator, and
* may (but is not guaranteed to) reflect any modifications
* subsequent to construction.
*
* @return an iterator over the elements in this deque in reverse order
*/
public Iterator<E> descendingIterator() {
return new DescendingItr();
}
/**
* Base class for Iterators for LinkedBlockingDeque
*/
private abstract class AbstractItr implements Iterator<E> {
/**
* The next node to return in next()
*/
Node<E> next;
/**
* nextItem holds on to item fields because once we claim that
* an element exists in hasNext(), we must return item read
* under lock (in advance()) even if it was in the process of
* being removed when hasNext() was called.
*/
E nextItem;
/**
* Node returned by most recent call to next. Needed by remove.
* Reset to null if this element is deleted by a call to remove.
*/
private Node<E> lastRet;
abstract Node<E> firstNode();
abstract Node<E> nextNode(Node<E> n);
AbstractItr() {
// set to initial position
final ReentrantLock lock = LinkedBlockingDeque.this.lock;
lock.lock();
try {
next = firstNode();
nextItem = (next == null) ? null : next.item;
} finally {
lock.unlock();
}
}
/**
* Returns the successor node of the given non-null, but
* possibly previously deleted, node.
*/
private Node<E> succ(Node<E> n) {
// Chains of deleted nodes ending in null or self-links
// are possible if multiple interior nodes are removed.
for (;;) {
Node<E> s = nextNode(n);
if (s == null)
return null;
else if (s.item != null)
return s;
else if (s == n)
return firstNode();
else
n = s;
}
}
/**
* Advances next.
*/
void advance() {
final ReentrantLock lock = LinkedBlockingDeque.this.lock;
lock.lock();
try {
// assert next != null;
next = succ(next);
nextItem = (next == null) ? null : next.item;
} finally {
lock.unlock();
}
}
public boolean hasNext() {
return next != null;
}
public E next() {
if (next == null)
throw new NoSuchElementException();
lastRet = next;
E x = nextItem;
advance();
return x;
}
public void remove() {
Node<E> n = lastRet;
if (n == null)
throw new IllegalStateException();
lastRet = null;
final ReentrantLock lock = LinkedBlockingDeque.this.lock;
lock.lock();
try {
if (n.item != null)
unlink(n);
} finally {
lock.unlock();
}
}
}
/** Forward iterator */
private class Itr extends AbstractItr {
Node<E> firstNode() { return first; }
Node<E> nextNode(Node<E> n) { return n.next; }
}
/** Descending iterator */
private class DescendingItr extends AbstractItr {
Node<E> firstNode() { return last; }
Node<E> nextNode(Node<E> n) { return n.prev; }
}
/**
* Save the state of this deque to a stream (that is, serialize it).
*
* @serialData The capacity (int), followed by elements (each an
* {@code Object}) in the proper order, followed by a null
* @param s the stream
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
final ReentrantLock lock = this.lock;
lock.lock();
try {
// Write out capacity and any hidden stuff
s.defaultWriteObject();
// Write out all elements in the proper order.
for (Node<E> p = first; p != null; p = p.next)
s.writeObject(p.item);
// Use trailing null as sentinel
s.writeObject(null);
} finally {
lock.unlock();
}
}
/**
* Reconstitute this deque from a stream (that is,
* deserialize it).
* @param s the stream
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
count = 0;
first = null;
last = null;
// Read in all elements and place in queue
for (;;) {
@SuppressWarnings("unchecked")
E item = (E)s.readObject();
if (item == null)
break;
add(item);
}
}
}
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