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Diffstat (limited to 'libjava/classpath/external/jsr166/java/util/concurrent/BlockingDeque.java')
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1 files changed, 613 insertions, 0 deletions
diff --git a/libjava/classpath/external/jsr166/java/util/concurrent/BlockingDeque.java b/libjava/classpath/external/jsr166/java/util/concurrent/BlockingDeque.java new file mode 100644 index 00000000000..d77a96555ad --- /dev/null +++ b/libjava/classpath/external/jsr166/java/util/concurrent/BlockingDeque.java @@ -0,0 +1,613 @@ +/* + * 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 java.util.concurrent; +import java.util.*; + +/** + * 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(Object) offerFirst(e)}</td> + * <td>{@link #putFirst putFirst(e)}</td> + * <td>{@link #offerFirst(Object, long, TimeUnit) 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(Object) offerLast(e)}</td> + * <td>{@link #putLast putLast(e)}</td> + * <td>{@link #offerLast(Object, long, TimeUnit) 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(Object) add(e)}</td> + * <td>{@link #addLast(Object) addLast(e)}</td> + * </tr> + * <tr> + * <td>{@link #offer(Object) offer(e)}</td> + * <td>{@link #offerLast(Object) offerLast(e)}</td> + * </tr> + * <tr> + * <td>{@link #put(Object) put(e)}</td> + * <td>{@link #putLast(Object) putLast(e)}</td> + * </tr> + * <tr> + * <td>{@link #offer(Object, long, TimeUnit) offer(e, time, unit)}</td> + * <td>{@link #offerLast(Object, long, TimeUnit) 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(Object) 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(Object) 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(Object) 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(Object) 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(Object) offer}. + * + * <p>This method is equivalent to {@link #addLast(Object) 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(Object) 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(Object) 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(Object,long,TimeUnit) 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(Object) 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(Object) addFirst}. + * + * @throws IllegalStateException {@inheritDoc} + * @throws ClassCastException {@inheritDoc} + * @throws NullPointerException if the specified element is null + * @throws IllegalArgumentException {@inheritDoc} + */ + void push(E e); +} |