8019381: HashMap.isEmpty is non-final, potential issues for get/remove
Reviewed-by: chegar, mduigou
--- a/jdk/src/share/classes/java/util/HashMap.java Thu Jul 04 20:00:20 2013 +0100
+++ b/jdk/src/share/classes/java/util/HashMap.java Fri Jul 05 10:51:54 2013 +0800
@@ -1013,7 +1013,7 @@
*/
@SuppressWarnings("unchecked")
final Entry<K,V> getEntry(Object key) {
- if (isEmpty()) {
+ if (size == 0) {
return null;
}
if (key == null) {
@@ -1468,7 +1468,7 @@
@Override
public boolean remove(Object key, Object value) {
- if (isEmpty()) {
+ if (size == 0) {
return false;
}
if (key == null) {
@@ -1531,7 +1531,7 @@
@Override
public boolean replace(K key, V oldValue, V newValue) {
- if (isEmpty()) {
+ if (size == 0) {
return false;
}
if (key == null) {
@@ -1574,7 +1574,7 @@
@Override
public V replace(K key, V value) {
- if (isEmpty()) {
+ if (size == 0) {
return null;
}
if (key == null) {
@@ -1694,7 +1694,7 @@
@Override
public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
- if (isEmpty()) {
+ if (size == 0) {
return null;
}
if (key == null) {
@@ -1980,7 +1980,7 @@
* TreeNode in a TreeBin.
*/
final Entry<K,V> removeEntryForKey(Object key) {
- if (isEmpty()) {
+ if (size == 0) {
return null;
}
if (key == null) {
@@ -2040,7 +2040,7 @@
* for matching.
*/
final Entry<K,V> removeMapping(Object o) {
- if (isEmpty() || !(o instanceof Map.Entry))
+ if (size == 0 || !(o instanceof Map.Entry))
return null;
Map.Entry<?,?> entry = (Map.Entry<?,?>) o;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/HashMap/OverrideIsEmpty.java Fri Jul 05 10:51:54 2013 +0800
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * Portions Copyright (c) 2013 IBM Corporation
+ */
+
+/**
+ * @test
+ * @bug 8019381
+ * @summary Verify that we do not get exception when we override isEmpty()
+ * in a subclass of HashMap
+ * @author zhangshj@linux.vnet.ibm.com
+ */
+
+import java.util.function.BiFunction;
+import java.util.HashMap;
+
+public class OverrideIsEmpty {
+ public static class NotEmptyHashMap<K,V> extends HashMap<K,V> {
+ private K alwaysExistingKey;
+ private V alwaysExistingValue;
+
+ @Override
+ public V get(Object key) {
+ if (key == alwaysExistingKey) {
+ return alwaysExistingValue;
+ }
+ return super.get(key);
+ }
+
+ @Override
+ public int size() {
+ return super.size() + 1;
+ }
+
+ @Override
+ public boolean isEmpty() {
+ return size() == 0;
+ }
+ }
+
+ public static void main(String[] args) {
+ NotEmptyHashMap<Object, Object> map = new NotEmptyHashMap<>();
+ Object key = new Object();
+ Object value = new Object();
+ map.get(key);
+ map.remove(key);
+ map.replace(key, value, null);
+ map.replace(key, value);
+ map.computeIfPresent(key, new BiFunction<Object, Object, Object>() {
+ public Object apply(Object key, Object oldValue) {
+ return oldValue;
+ }
+ });
+ }
+}
+