--- 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 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(); }