--- jsr166/src/jsr166x/Deque.java 2004/12/05 21:15:31 1.3
+++ jsr166/src/jsr166x/Deque.java 2015/01/18 20:17:33 1.13
@@ -1,32 +1,34 @@
/*
* 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
+ * at http://creativecommons.org/publicdomain/zero/1.0/
*/
package jsr166x; // XXX This belongs in java.util!!! XXX
+
import java.util.*; // XXX This import goes away XXX
/**
- * A linear collection that supports element insertion and removal
- * at both ends. The name deque is short for "double ended
- * queue" and is usually pronounced "deck". Most Deque
+ * A linear collection that supports element insertion and removal at
+ * both ends. The name deque is short for "double ended queue"
+ * and is usually pronounced "deck". Most {@code Deque}
* 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.
*
- *
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
- * null or false, depending on the operation). The latter
- * form of the insert operation is designed specifically for use with
- * capacity-restricted Deque implementations; in most implementations,
- * insert operations cannot fail.
- *
- *
The twelve methods described above are are summarized in the
- * follwoing table:
- *
+ *
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 {@code null} or {@code false}, depending on
+ * the operation). The latter form of the insert operation is
+ * designed specifically for use with capacity-restricted
+ * {@code Deque} implementations; in most implementations, insert
+ * operations cannot fail.
+ *
+ *
The twelve methods described above are summarized in the
+ * following table:
+ *
*
*
* |
@@ -56,9 +58,9 @@ import java.util.*; // XXX This impor
*
*
* Examine |
- * {@link #firstElement firstElement()} |
+ * {@link #getFirst getFirst()} |
* {@link #peekFirst peekFirst()} |
- * {@link #lastElement lastElement()} |
+ * {@link #getLast getLast()} |
* {@link #peekLast peekLast()} |
*
*
@@ -66,13 +68,13 @@ import java.util.*; // XXX This impor
* 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 to the end of the deque and removed from the beginning. The methods
- * inherited from the Queue interface are precisely equivalent to
- * Deque methods as indicated in the following table:
+ * inherited from the {@code Queue} interface are precisely equivalent to
+ * {@code Deque} methods as indicated in the following table:
*
*
*
- * Queue Method |
- * Equivalent Deque Method |
+ * {@code Queue} Method |
+ * Equivalent {@code Deque} Method |
*
*
*
@@ -97,7 +99,7 @@ import java.util.*; // XXX This impor
*
*
* {@link java.util.Queue#element element()} |
- * {@link #firstElement firstElement()} |
+ * {@link #getFirst getFirst()} |
*
*
*
@@ -105,12 +107,12 @@ import java.util.*; // XXX This impor
* interface should be used in preference to the legacy {@link Stack} class.
* When a dequeue is used as a stack, elements are pushed and popped from the
* beginning of the deque. Stack methods are precisely equivalent to
- * Deque methods as indicated in the table below:
+ * {@code Deque} methods as indicated in the table below:
*
*
*
* Stack Method |
- * Equivalent Deque Method |
+ * Equivalent {@code Deque} Method |
*
*
*
@@ -126,28 +128,29 @@ import java.util.*; // XXX This impor
* {@link #peekFirst peekFirst()} |
*
*
- * 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.
- *
- *
This inteface provides two methods to to remove interior elements,
- * {@link #removeFirstOccurrence removeFirstOccurrence} and {@link
- * #removeLastOccurrence removeLastOccurrence}. Unlike the {@link List}
- * interface, this interface does not provide support for indexed access to
- * elements.
- *
- *
While Deque implementations are not strictly required to
- * prohibit the insertion of null elements, they are strongly encouraged to do
- * so. Users of any Deque implementations that do allow null
- * elements are strongly encouraged not to take advantage of the
- * ability to insert nulls. This is so because null is used as a
- * special return value by various methods to indicated that the deque is
- * empty.
- *
- *
Deque implementations generally do not define
- * element-based versions of the equals and hashCode
+ *
+ *
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.
+ *
+ *
This interface provides two methods to remove interior
+ * elements, {@link #removeFirstOccurrence removeFirstOccurrence} and
+ * {@link #removeLastOccurrence removeLastOccurrence}. Unlike the
+ * {@link List} interface, this interface does not provide support for
+ * indexed access to elements.
+ *
+ *
While {@code Deque} implementations are not strictly required
+ * to prohibit the insertion of null elements, they are strongly
+ * encouraged to do so. Users of any {@code Deque} implementations
+ * that do allow null elements are strongly encouraged not to
+ * take advantage of the ability to insert nulls. This is so because
+ * {@code null} is used as a special return value by various methods
+ * to indicated that the deque is empty.
+ *
+ *
{@code Deque} implementations generally do not define
+ * element-based versions of the {@code equals} and {@code hashCode}
* methods, but instead inherit the identity-based versions from class
- * Object.
+ * {@code Object}.
*
*
This interface is a member of the Java Collections
@@ -162,13 +165,13 @@ public interface Deque extends Queue<
/**
* Inserts the specified element to the front this deque unless it would
* violate capacity restrictions. When using a capacity-restricted deque,
- * this method is generally preferable to method addFirst, which
+ * this method is generally preferable to method {@code addFirst}, which
* can fail to insert an element only by throwing an exception.
*
* @param e the element to insert
- * @return true if it was possible to insert the element,
- * else false
- * @throws NullPointerException if e is null and this
+ * @return {@code true} if it was possible to insert the element,
+ * else {@code false}
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
boolean offerFirst(E e);
@@ -176,13 +179,13 @@ public interface Deque extends Queue<
/**
* Inserts the specified element to the end of this deque unless it would
* violate capacity restrictions. When using a capacity-restricted deque,
- * this method is generally preferable to method addLast which
+ * this method is generally preferable to method {@code addLast} which
* can fail to insert an element only by throwing an exception.
*
* @param e the element to insert
- * @return true if it was possible to insert the element,
- * else false
- * @throws NullPointerException if e is null and this
+ * @return {@code true} if it was possible to insert the element,
+ * else {@code false}
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
boolean offerLast(E e);
@@ -194,7 +197,7 @@ public interface Deque extends Queue<
* @param e the element to insert
* @throws IllegalStateException if it was not possible to insert
* the element due to capacity restrictions
- * @throws NullPointerException if e is null and this
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
void addFirst(E e);
@@ -206,32 +209,32 @@ public interface Deque extends Queue<
* @param e the element to insert
* @throws IllegalStateException if it was not possible to insert
* the element due to capacity restrictions
- * @throws NullPointerException if e is null and this
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
void addLast(E e);
/**
* Retrieves and removes the first element of this deque, or
- * null if this deque is empty.
+ * {@code null} if this deque is empty.
*
- * @return the first element of this deque, or null if
+ * @return the first element of this deque, or {@code null} if
* this deque is empty
*/
E pollFirst();
/**
* Retrieves and removes the last element of this deque, or
- * null if this deque is empty.
+ * {@code null} if this deque is empty.
*
- * @return the last element of this deque, or null if
+ * @return the last element of this deque, or {@code null} if
* this deque is empty
*/
E pollLast();
/**
* Removes and returns the first element of this deque. This method
- * differs from the pollFirst method only in that it throws an
+ * differs from the {@code pollFirst} method only in that it throws an
* exception if this deque is empty.
*
* @return the first element of this deque
@@ -241,7 +244,7 @@ public interface Deque extends Queue<
/**
* Retrieves and removes the last element of this deque. This method
- * differs from the pollLast method only in that it throws an
+ * differs from the {@code pollLast} method only in that it throws an
* exception if this deque is empty.
*
* @return the last element of this deque
@@ -251,65 +254,65 @@ public interface Deque extends Queue<
/**
* Retrieves, but does not remove, the first element of this deque,
- * returning null if this deque is empty.
+ * returning {@code null} if this deque is empty.
*
- * @return the first element of this deque, or null if
+ * @return the first element of this deque, or {@code null} if
* this deque is empty
*/
E peekFirst();
/**
* Retrieves, but does not remove, the last element of this deque,
- * returning null if this deque is empty.
+ * returning {@code null} if this deque is empty.
*
- * @return the last element of this deque, or null if this deque
+ * @return the last element of this deque, or {@code null} if this deque
* is empty
*/
E peekLast();
/**
* Retrieves, but does not remove, the first element of this
- * deque. This method differs from the peek method only
+ * deque. This method differs from the {@code peek} method only
* in that it throws an exception if this deque is empty.
*
* @return the first element of this deque
* @throws NoSuchElementException if this deque is empty
*/
- E firstElement();
+ E getFirst();
/**
* Retrieves, but does not remove, the last element of this
- * deque. This method differs from the peek method only
+ * deque. This method differs from the {@code peek} method only
* in that it throws an exception if this deque is empty.
*
* @return the last element of this deque
* @throws NoSuchElementException if this deque is empty
*/
- E lastElement();
+ E getLast();
/**
* Removes the first occurrence of the specified element in this
* deque. If the deque does not contain the element, it is
- * unchanged. More formally, removes the first element e
- * such that (o==null ? e==null : o.equals(e)) (if
+ * unchanged. More formally, removes the first element {@code e}
+ * such that {@code (o==null ? e==null : o.equals(e))} (if
* such an element exists).
*
* @param e element to be removed from this deque, if present
- * @return true if the deque contained the specified element
- * @throws NullPointerException if the specified element is null
+ * @return {@code true} if the deque contained the specified element
+ * @throws NullPointerException if the specified element is {@code null}
*/
boolean removeFirstOccurrence(Object e);
/**
* Removes the last occurrence of the specified element in this
* deque. If the deque does not contain the element, it is
- * unchanged. More formally, removes the last element e
- * such that (o==null ? e==null : o.equals(e)) (if
+ * unchanged. More formally, removes the last element {@code e}
+ * such that {@code (o==null ? e==null : o.equals(e))} (if
* such an element exists).
*
* @param e element to be removed from this deque, if present
- * @return true if the deque contained the specified element
- * @throws NullPointerException if the specified element is null
+ * @return {@code true} if the deque contained the specified element
+ * @throws NullPointerException if the specified element is {@code null}
*/
boolean removeLastOccurrence(Object e);
@@ -327,9 +330,9 @@ public interface Deque extends Queue<
* This method is equivalent to {@link #offerLast}.
*
* @param e the element to insert
- * @return true if it was possible to insert the element,
- * else false
- * @throws NullPointerException if e is null and this
+ * @return {@code true} if it was possible to insert the element,
+ * else {@code false}
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
boolean offer(E e);
@@ -337,35 +340,35 @@ public interface Deque extends Queue<
/**
* Inserts the specified element into the queue represented by this
* deque unless it would violate capacity restrictions. In other words,
- * inserts the specified element as the last element of this deque.
+ * inserts the specified element as the last element of this deque.
*
* This method is equivalent to {@link #addLast}.
*
* @param e the element to insert
- * @return true (as per the spec for {@link Collection#add})
+ * @return {@code true} (as per the spec for {@link Collection#add})
* @throws IllegalStateException if it was not possible to insert
* the element due to capacity restrictions
- * @throws NullPointerException if e is null and this
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
boolean add(E e);
/**
* Retrieves and removes the head of the queue represented by
- * this deque, or null if this deque is empty. In other words,
- * retrieves and removes the first element of this deque, or null
+ * this deque, or {@code null} if this deque is empty. In other words,
+ * retrieves and removes the first element of this deque, or {@code null}
* if this deque is empty.
*
*
This method is equivalent to {@link #pollFirst()}.
*
- * @return the first element of this deque, or null if
+ * @return the first element of this deque, or {@code null} if
* this deque is empty
*/
E poll();
/**
* Retrieves and removes the head of the queue represented by this deque.
- * This method differs from the poll method only in that it
+ * This method differs from the {@code poll} method only in that it
* throws an exception if this deque is empty.
*
*
This method is equivalent to {@link #removeFirst()}.
@@ -377,21 +380,21 @@ public interface Deque extends Queue<
/**
* Retrieves, but does not remove, the head of the queue represented by
- * this deque, returning null if this deque is empty.
+ * this deque, returning {@code null} if this deque is empty.
*
- * This method is equivalent to {@link #peekFirst()}
+ *
This method is equivalent to {@link #peekFirst()}.
*
* @return the head of the queue represented by this deque, or
- * null if this deque is empty
+ * {@code null} if this deque is empty
*/
E peek();
/**
* Retrieves, but does not remove, the head of the queue represented by
- * this deque. This method differs from the peek method only in
+ * this deque. This method differs from the {@code peek} method only in
* that it throws an exception if this deque is empty.
*
- *
This method is equivalent to {@link #firstElement()}
+ *
This method is equivalent to {@link #getFirst()}.
*
* @return the head of the queue represented by this deque
* @throws NoSuchElementException if this deque is empty
@@ -410,14 +413,14 @@ public interface Deque extends Queue<
*
* @throws IllegalStateException if it was not possible to insert
* the element due to capacity restrictions
- * @throws NullPointerException if e is null and this
+ * @throws NullPointerException if {@code e} is null and this
* deque does not permit null elements
*/
void push(E e);
/**
* Pops an element from the stack represented by this deque. In other
- * words, removes and returns the the first element of this deque.
+ * words, removes and returns the first element of this deque.
*
* This method is equivalent to {@link #removeFirst()}.
*
@@ -433,8 +436,8 @@ public interface Deque extends Queue<
/**
* Returns an iterator over the elements in this deque. The elements
* will be ordered from first (head) to last (tail).
- *
- * @return an Iterator over the elements in this deque
+ *
+ * @return an {@code Iterator} over the elements in this deque
*/
Iterator iterator();
}