/* $Id: RuleSetCache.java 992080 2010-09-02 19:46:29Z simonetripodi $
*
* 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.commons.digester.annotations.internal;
import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;
import org.apache.commons.digester.annotations.FromAnnotationsRuleSet;
Simple in-memory LRU cache implementation.
Since: 2.1
/**
* Simple in-memory LRU cache implementation.
*
* @since 2.1
*/
public final class RuleSetCache implements Serializable {
This class serialVersionUID.
/**
* This class serialVersionUID.
*/
private static final long serialVersionUID = 1L;
The fixed cache size.
/**
* The fixed cache size.
*/
private final int cacheSize = 255;
The fixed cache load facor.
/**
* The fixed cache load facor.
*/
private final float loadFactor = 0.75f;
The fixed cache capacity.
/**
* The fixed cache capacity.
*/
private final int capacity = (int) Math.ceil(this.cacheSize / this.loadFactor) + 1;
The map that implements the LRU cache.
/**
* The map that implements the LRU cache.
*/
private final Map<Class<?>, FromAnnotationsRuleSet> data =
new LinkedHashMap<Class<?>, FromAnnotationsRuleSet>(capacity, loadFactor) {
This class serialVersionUID.
/**
* This class serialVersionUID.
*/
private static final long serialVersionUID = 1L;
{@inheritDoc}
/**
* {@inheritDoc}
*/
@Override
protected boolean removeEldestEntry(Map.Entry<Class<?>, FromAnnotationsRuleSet> eldest) {
return size() > cacheSize;
}
};
Returns true if this cache contains a mapping for the specified key.
Params: - key – key whose presence in this map is to be tested.
Returns: true if this map contains a mapping for the specified key, false
otherwise.
/**
* Returns true if this cache contains a mapping for the specified key.
*
* @param key key whose presence in this map is to be tested.
* @return true if this map contains a mapping for the specified key, false
* otherwise.
*/
public boolean containsKey(Class<?> key) {
checkKey(key);
return this.data.containsKey(key);
}
Returns the value to which the specified key is cached, or null if this
cache contains no mapping for the key.
Key parameter must not be null.
Params: - key – the key has to be checked it is present, it must not be null.
Returns: the value to which the specified key is cached, null if this
cache contains no mapping for the key.
/**
* Returns the value to which the specified key is cached, or null if this
* cache contains no mapping for the key.
*
* Key parameter must not be null.
*
* @param key the key has to be checked it is present, it must not be null.
* @return the value to which the specified key is cached, null if this
* cache contains no mapping for the key.
*/
public FromAnnotationsRuleSet get(Class<?> key) {
checkKey(key);
return this.data.get(key);
}
Associates the specified value with the specified key in this cache.
Key parameter must not be null.
Params: - key – key with which the specified value is to be associated.
- value – value to be associated with the specified key.
/**
* Associates the specified value with the specified key in this cache.
*
* Key parameter must not be null.
*
* @param key key with which the specified value is to be associated.
* @param value value to be associated with the specified key.
*/
public void put(Class<?> key, FromAnnotationsRuleSet value) {
checkKey(key);
this.data.put(key, value);
}
Verify that a key is not null.
Params: - key – the key object.
Type parameters: - <T> – the generic key type.
/**
* Verify that a key is not null.
*
* @param <T> the generic key type.
* @param key the key object.
*/
private static void checkKey(Class<?> key) {
if (key == null) {
throw new IllegalArgumentException("null keys not supported");
}
}
}