--- jsr166/src/main/java/util/PriorityQueue.java 2003/07/28 09:40:07 1.12
+++ jsr166/src/main/java/util/PriorityQueue.java 2003/07/31 07:18:02 1.15
@@ -3,15 +3,15 @@
/**
* An unbounded priority queue based on a priority heap. This queue orders
* elements according to an order specified at construction time, which is
- * specified in the same manner as {@link TreeSet} and {@link TreeMap}:
+ * specified in the same manner as {@link TreeSet} and {@link TreeMap}:
* elements are ordered
* either according to their natural order (see {@link Comparable}), or
* according to a {@link Comparator}, depending on which constructor is used.
* The head of this queue is the least element with respect to the
- * specified ordering. If multiple elements are tied for least value, the
- * head is one of those elements. A priority queue does not permit
+ * specified ordering. If multiple elements are tied for least value, the
+ * head is one of those elements. A priority queue does not permit
* null elements.
- *
+ *
*
The {@link #remove()} and {@link #poll()} methods remove and
* return the head of the queue.
*
@@ -38,7 +38,7 @@
* @author Josh Bloch
*/
public class PriorityQueue extends AbstractQueue
- implements Queue, Sorted, java.io.Serializable {
+ implements Queue, java.io.Serializable {
private static final int DEFAULT_INITIAL_CAPACITY = 11;
@@ -102,10 +102,12 @@ public class PriorityQueue extends Ab
* @param comparator the comparator used to order this priority queue.
* If null then the order depends on the elements' natural
* ordering.
+ * @throws IllegalArgumentException if initialCapacity is less
+ * than 1
*/
public PriorityQueue(int initialCapacity, Comparator comparator) {
if (initialCapacity < 1)
- initialCapacity = 1;
+ throw new IllegalArgumentException();
queue = (E[]) new Object[initialCapacity + 1];
this.comparator = comparator;
}
@@ -113,7 +115,8 @@ public class PriorityQueue extends Ab
/**
* Create a PriorityQueue containing the elements in the specified
* collection. The priority queue has an initial capacity of 110% of the
- * size of the specified collection. If the specified collection
+ * size of the specified collection; or 1 if the collection is empty.
+ * If the specified collection
* implements the {@link Sorted} interface, the priority queue will be
* sorted according to the same comparator, or according to its elements'
* natural order if the collection is sorted according to its elements'
@@ -121,29 +124,31 @@ public class PriorityQueue extends Ab
* Sorted, the priority queue is ordered according to
* its elements' natural order.
*
- * @param initialElements the collection whose elements are to be placed
+ * @param c the collection whose elements are to be placed
* into this priority queue.
* @throws ClassCastException if elements of the specified collection
* cannot be compared to one another according to the priority
* queue's ordering.
- * @throws NullPointerException if the specified collection or an
- * element of the specified collection is null.
+ * @throws NullPointerException if c or any element within it
+ * is null
*/
- public PriorityQueue(Collection initialElements) {
- int sz = initialElements.size();
+ public PriorityQueue(Collection c) {
+ int sz = c.size();
int initialCapacity = (int)Math.min((sz * 110L) / 100,
Integer.MAX_VALUE - 1);
if (initialCapacity < 1)
initialCapacity = 1;
+
queue = (E[]) new Object[initialCapacity + 1];
- if (initialElements instanceof Sorted) {
- comparator = ((Sorted)initialElements).comparator();
- for (Iterator i = initialElements.iterator(); i.hasNext(); )
+ if (c instanceof Sorted) {
+ // FIXME: this code assumes too much
+ comparator = ((Sorted)c).comparator();
+ for (Iterator i = c.iterator(); i.hasNext(); )
queue[++size] = i.next();
} else {
comparator = null;
- for (Iterator i = initialElements.iterator(); i.hasNext(); )
+ for (Iterator i = c.iterator(); i.hasNext(); )
add(i.next());
}
}
@@ -194,24 +199,27 @@ public class PriorityQueue extends Ab
/**
* @throws NullPointerException if the specified element is null.
+ * @throws ClassCastException if the specified element cannot be compared
+ * with elements currently in the priority queue according
+ * to the priority queue's ordering.
*/
public boolean add(E element) {
return super.add(element);
}
- // /**
- // * @throws NullPointerException if any element is null.
- // */
- // public boolean addAll(Collection c) {
- // return super.addAll(c);
- // }
-
/**
- * @throws NullPointerException if the specified element is null.
+ * @throws NullPointerException if any element is null.
+ * @throws ClassCastException if any element cannot be compared
+ * with elements currently in the priority queue according
+ * to the priority queue's ordering.
*/
+ public boolean addAll(Collection extends E> c) {
+ return super.addAll(c);
+ }
+
public boolean remove(Object o) {
if (o == null)
- throw new NullPointerException();
+ return false;
if (comparator == null) {
for (int i = 1; i <= size; i++) {
@@ -231,14 +239,6 @@ public class PriorityQueue extends Ab
return false;
}
- /**
- * Returns an iterator over the elements in this priority queue. The
- * elements of the priority queue will be returned by this iterator in the
- * order specified by the queue, which is to say the order they would be
- * returned by repeated calls to poll.
- *
- * @return an Iterator over the elements in this priority queue.
- */
public Iterator iterator() {
return new Itr();
}