Fix up PriorityQueue.iterator() to support remove().
Change-Id: Iedc73edafaaf0c81ef4bdbfe3b1d144a487e4a81
Review-Link: https://gwt-review.googlesource.com/#/c/18900/
diff --git a/user/super/com/google/gwt/emul/java/util/PriorityQueue.java b/user/super/com/google/gwt/emul/java/util/PriorityQueue.java
index 59de7e9..90480b8 100644
--- a/user/super/com/google/gwt/emul/java/util/PriorityQueue.java
+++ b/user/super/com/google/gwt/emul/java/util/PriorityQueue.java
@@ -124,8 +124,31 @@
@Override
public Iterator<E> iterator() {
- // TODO(jat): PriorityQueue is supposed to have a modifiable iterator.
- return Collections.unmodifiableList(heap).iterator();
+ return new Iterator<E>() {
+ private E current = null;
+ // Make a copy of the elements so that remove() doesn't screw up the order.
+ Iterator<E> elementsToTraverse = new ArrayList<>(heap).iterator();
+ @Override
+ public boolean hasNext() {
+ return elementsToTraverse.hasNext();
+ }
+
+ @Override
+ public E next() {
+ current = elementsToTraverse.next();
+ return current;
+ }
+
+ @Override
+ public void remove() {
+ if (current == null) {
+ throw new IllegalStateException("remove() called before iteration or removed already.");
+ }
+ // Remove the current element. Keep on iterating.
+ PriorityQueue.this.remove(current);
+ current = null;
+ }
+ };
}
@Override
diff --git a/user/test/com/google/gwt/emultest/java/util/PriorityQueueTest.java b/user/test/com/google/gwt/emultest/java/util/PriorityQueueTest.java
index 6b07adf..4f10055 100644
--- a/user/test/com/google/gwt/emultest/java/util/PriorityQueueTest.java
+++ b/user/test/com/google/gwt/emultest/java/util/PriorityQueueTest.java
@@ -1,12 +1,12 @@
/*
* Copyright 2008 Google Inc.
- *
+ *
* 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
@@ -21,6 +21,7 @@
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
+import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.TreeSet;
@@ -186,7 +187,7 @@
assertTrue(queue.contains(3));
assertFalse(queue.contains(4));
}
-
+
public void testPeekElement() {
PriorityQueue<Integer> queue = new PriorityQueue<>();
try {
@@ -245,5 +246,40 @@
PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
addArray(pq, values);
return pq;
- }
+ }
+
+ public void testIteratorRemove() {
+ PriorityQueue<Integer> queue = new PriorityQueue<>();
+ queue.add(1);
+ queue.add(2);
+ queue.add(3);
+ queue.add(5);
+ queue.add(6);
+
+ int sum = 0;
+ Iterator<Integer> it = queue.iterator();
+ while (it.hasNext()) {
+ int i = it.next();
+ if (i == 2) {
+ it.remove();
+ }
+ sum += i;
+ }
+ assertEquals(17, sum);
+ assertEquals(4, queue.size());
+
+ try {
+ queue.iterator().remove();
+ fail();
+ } catch (IllegalStateException e) { }
+
+ try {
+ Iterator<Integer> itt = queue.iterator();
+ while (itt.hasNext()) {
+ it.remove();
+ it.remove();
+ fail();
+ }
+ } catch (IllegalStateException e) { };
+ }
}
