WALA/com.ibm.wala.util/src/com/ibm/wala/util/collections/ParanoidHashMap.java

77 lines
2.2 KiB
Java

/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.util.collections;
import java.lang.reflect.Method;
import java.util.LinkedHashMap;
import java.util.Map;
import com.ibm.wala.util.debug.UnimplementedError;
/**
* a debugging aid. This implementation complains if you stick an object in here which appears to use System.identityHashCode()
*/
public class ParanoidHashMap<K, V> extends LinkedHashMap<K, V> {
public static final long serialVersionUID = 909018793791787198L;
/**
* @param t
* @throws NullPointerException if t is null
*/
public ParanoidHashMap(Map<K, V> t) throws NullPointerException {
super(t.size());
putAll(t);
}
public ParanoidHashMap(int size) {
super(size);
}
public ParanoidHashMap() {
}
/*
* @see java.util.Map#put(java.lang.Object, java.lang.Object)
*/
@Override
public V put(K arg0, V arg1) {
assertOverridesHashCode(arg0);
return super.put(arg0, arg1);
}
public static void assertOverridesHashCode(Object o) throws UnimplementedError {
if (o != null && o.hashCode() == System.identityHashCode(o)) {
try {
Method method = o.getClass().getMethod("hashCode");
if (method.getDeclaringClass() == Object.class) {
assert false : o.getClass().toString();
}
} catch (Exception e) {
assert false : "Could not find hashCode method";
}
}
}
/*
* @see java.util.Map#putAll(java.util.Map)
*/
@Override
public void putAll(Map<? extends K, ? extends V> arg0) {
if (arg0 == null) {
throw new IllegalArgumentException("arg0 is null");
}
for (Map.Entry<? extends K, ? extends V> E : arg0.entrySet()) {
put(E.getKey(), E.getValue());
}
}
}