com.codename1.ui.util.WeakHashMap Maven / Gradle / Ivy
/*
* Copyright (c) 2012, Codename One 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. Codename One designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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 Codename One through http://www.codenameone.com/ if you
* need additional information or have any questions.
*/
package com.codename1.ui.util;
import com.codename1.ui.Display;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* Helper weak hash map substitute
* @author Shai Almog
*/
public class WeakHashMap implements Map {
private final HashMap map = new HashMap();
/**
* {@inheritDoc}
*/
@Override
public int size() {
return map.size();
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEmpty() {
return map.isEmpty();
}
/**
* {@inheritDoc}
*/
@Override
public boolean containsKey(Object key) {
return map.containsKey(key);
}
/**
* This method is unsupported in the weak hash map
*/
@Override
public boolean containsValue(Object value) {
throw new RuntimeException();
}
/**
* {@inheritDoc}
*/
@Override
public V get(Object key) {
Object o = map.get(key);
if(o == null) {
return null;
}
return (V) Display.getInstance().extractHardRef(o);
}
/**
* {@inheritDoc}
*/
@Override
public V put(K key, V value) {
map.put(key, Display.getInstance().createSoftWeakRef(value));
return value;
}
/**
* {@inheritDoc}
*/
@Override
public V remove(Object key) {
Object o = map.remove(key);
if(o == null) {
return null;
}
return (V) Display.getInstance().extractHardRef(o);
}
/**
* {@inheritDoc}
*/
@Override
public void putAll(Map m) {
for(K o : m.keySet()) {
put(o, m.get(o));
}
}
/**
* {@inheritDoc}
*/
@Override
public void clear() {
map.clear();
}
/**
* {@inheritDoc}
*/
@Override
public Set keySet() {
return map.keySet();
}
/**
* Unsupported operation
*/
@Override
public Collection values() {
throw new RuntimeException();
}
/**
* Unsupported operation
*/
@Override
public Set> entrySet() {
throw new RuntimeException();
}
}