/* | |
* Licensed to the Apache Software Foundation (ASF) under one | |
* or more contributor license agreements. See the NOTICE file | |
* distributed with this work for additional information | |
* regarding copyright ownership. The ASF licenses this file | |
* to you 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 License for the | |
* specific language governing permissions and limitations | |
* under the License. | |
*/ | |
package org.apache.myfaces.extensions.validator.util; | |
import java.util.concurrent.ConcurrentHashMap; | |
/** | |
* in some cases we have to store null values to avoid re-evaluation | |
* | |
*/ | |
public class NullValueAwareConcurrentHashMap<K, V> extends ConcurrentHashMap<K, V> | |
{ | |
private static final long serialVersionUID = -7294527213622879543L; | |
private V nullMarkerValue; | |
public NullValueAwareConcurrentHashMap(V nullMarkerValue) | |
{ | |
this.nullMarkerValue = nullMarkerValue; | |
} | |
public NullValueAwareConcurrentHashMap(Class<? extends V> nullMarkerValueClass) | |
{ | |
if(nullMarkerValueClass.getName().equals(Object.class.getName())) | |
{ | |
//noinspection unchecked | |
nullMarkerValue = (V)new DefaultNullMarker(); | |
} | |
else if(nullMarkerValueClass.getName().equals(String.class.getName())) | |
{ | |
//noinspection unchecked | |
nullMarkerValue = (V)"{null}"; | |
} | |
else if(nullMarkerValueClass.getName().equals(Class.class.getName())) | |
{ | |
//noinspection unchecked | |
nullMarkerValue = (V)Void.class.getClass(); | |
} | |
else | |
{ | |
nullMarkerValue = ClassUtils.tryToInstantiateClass(nullMarkerValueClass); | |
} | |
} | |
@Override | |
public V put(K key, V value) | |
{ | |
if(value == null) | |
{ | |
return super.put(key, nullMarkerValue); | |
} | |
return super.put(key, value); | |
} | |
@Override | |
public V get(Object key) | |
{ | |
V result = super.get(key); | |
if(nullMarkerValue.equals(result)) | |
{ | |
return null; | |
} | |
return result; | |
} | |
private class DefaultNullMarker | |
{ | |
} | |
} |