org.activiti.engine.impl.persistence.deploy.DefaultDeploymentCache Maven / Gradle / Ivy
/* Licensed 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.activiti.engine.impl.persistence.deploy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* Default cache: keep everything in memory, unless a limit is set.
*
*/
public class DefaultDeploymentCache implements DeploymentCache {
private static final Logger logger = LoggerFactory.getLogger(DefaultDeploymentCache.class);
protected Map cache;
/** Cache with no limit */
public DefaultDeploymentCache() {
this.cache = Collections.synchronizedMap(new HashMap());
}
/**
* Cache which has a hard limit: no more elements will be cached than the limit.
*/
public DefaultDeploymentCache(final int limit) {
this.cache = Collections.synchronizedMap(new LinkedHashMap(limit + 1, 0.75f, true) { // +1 is needed, because the entry is inserted first, before it is removed
// 0.75 is the default (see javadocs)
// true will keep the 'access-order', which is needed to have a real LRU cache
private static final long serialVersionUID = 1L;
protected boolean removeEldestEntry(Map.Entry eldest) {
boolean removeEldest = size() > limit;
if (removeEldest && logger.isTraceEnabled()) {
logger.trace("Cache limit is reached, {} will be evicted", eldest.getKey());
}
return removeEldest;
}
});
}
public T get(String id) {
return cache.get(id);
}
public void add(String id, T obj) {
cache.put(id, obj);
}
public void remove(String id) {
cache.remove(id);
}
@Override
public boolean contains(String id) {
return cache.containsKey(id);
}
public void clear() {
cache.clear();
}
// For testing purposes only
public int size() {
return cache.size();
}
}