EhCache.java
/*
* 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.shiro.cache.ehcache;
import net.sf.ehcache.Element;
import org.apache.shiro.cache.Cache;
import org.apache.shiro.cache.CacheException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.*;
/**
* Shiro {@link org.apache.shiro.cache.Cache} implementation that wraps an {@link net.sf.ehcache.Ehcache} instance.
*
* @since 0.2
*/
public class EhCache<K, V> implements Cache<K, V> {
/**
* Private internal log instance.
*/
private static final Logger log = LoggerFactory.getLogger(EhCache.class);
/**
* The wrapped Ehcache instance.
*/
private net.sf.ehcache.Ehcache cache;
/**
* Constructs a new EhCache instance with the given cache.
*
* @param cache - delegate EhCache instance this Shiro cache instance will wrap.
*/
public EhCache(net.sf.ehcache.Ehcache cache) {
if (cache == null) {
throw new IllegalArgumentException("Cache argument cannot be null.");
}
this.cache = cache;
}
/**
* Gets a value of an element which matches the given key.
*
* @param key the key of the element to return.
* @return The value placed into the cache with an earlier put, or null if not found or expired
*/
public V get(K key) throws CacheException {
try {
if (log.isTraceEnabled()) {
log.trace("Getting object from cache [" + cache.getName() + "] for key [" + key + "]");
}
if (key == null) {
return null;
} else {
Element element = cache.get(key);
if (element == null) {
if (log.isTraceEnabled()) {
log.trace("Element for [" + key + "] is null.");
}
return null;
} else {
//noinspection unchecked
return (V) element.getObjectValue();
}
}
} catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Puts an object into the cache.
*
* @param key the key.
* @param value the value.
*/
public V put(K key, V value) throws CacheException {
if (log.isTraceEnabled()) {
log.trace("Putting object in cache [" + cache.getName() + "] for key [" + key + "]");
}
try {
V previous = get(key);
Element element = new Element(key, value);
cache.put(element);
return previous;
} catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Removes the element which matches the key.
*
* <p>If no element matches, nothing is removed and no Exception is thrown.</p>
*
* @param key the key of the element to remove
*/
public V remove(K key) throws CacheException {
if (log.isTraceEnabled()) {
log.trace("Removing object from cache [" + cache.getName() + "] for key [" + key + "]");
}
try {
V previous = get(key);
cache.remove(key);
return previous;
} catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Removes all elements in the cache, but leaves the cache in a useable state.
*/
public void clear() throws CacheException {
if (log.isTraceEnabled()) {
log.trace("Clearing all objects from cache [" + cache.getName() + "]");
}
try {
cache.removeAll();
} catch (Throwable t) {
throw new CacheException(t);
}
}
public int size() {
try {
return cache.getSize();
} catch (Throwable t) {
throw new CacheException(t);
}
}
public Set<K> keys() {
try {
@SuppressWarnings({"unchecked"})
List<K> keys = cache.getKeys();
if (!isEmpty(keys)) {
return Collections.unmodifiableSet(new LinkedHashSet<K>(keys));
} else {
return Collections.emptySet();
}
} catch (Throwable t) {
throw new CacheException(t);
}
}
public Collection<V> values() {
try {
@SuppressWarnings({"unchecked"})
List<K> keys = cache.getKeys();
if (!isEmpty(keys)) {
List<V> values = new ArrayList<V>(keys.size());
for (K key : keys) {
V value = get(key);
if (value != null) {
values.add(value);
}
}
return Collections.unmodifiableList(values);
} else {
return Collections.emptyList();
}
} catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Returns the size (in bytes) that this EhCache is using in memory (RAM), or <code>-1</code> if that
* number is unknown or cannot be calculated.
*
* @return the size (in bytes) that this EhCache is using in memory (RAM), or <code>-1</code> if that
* number is unknown or cannot be calculated.
*/
public long getMemoryUsage() {
try {
return cache.calculateInMemorySize();
}
catch (Throwable t) {
return -1;
}
}
/**
* Returns the size (in bytes) that this EhCache's memory store is using (RAM), or <code>-1</code> if
* that number is unknown or cannot be calculated.
*
* @return the size (in bytes) that this EhCache's memory store is using (RAM), or <code>-1</code> if
* that number is unknown or cannot be calculated.
*/
public long getMemoryStoreSize() {
try {
return cache.getMemoryStoreSize();
}
catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Returns the size (in bytes) that this EhCache's disk store is consuming or <code>-1</code> if
* that number is unknown or cannot be calculated.
*
* @return the size (in bytes) that this EhCache's disk store is consuming or <code>-1</code> if
* that number is unknown or cannot be calculated.
*/
public long getDiskStoreSize() {
try {
return cache.getDiskStoreSize();
} catch (Throwable t) {
throw new CacheException(t);
}
}
/**
* Returns "EhCache [" + cache.getName() + "]"
*
* @return "EhCache [" + cache.getName() + "]"
*/
public String toString() {
return "EhCache [" + cache.getName() + "]";
}
//////////////////////////
// From CollectionUtils //
//////////////////////////
// CollectionUtils cannot be removed from shiro-core until 2.0 as it has a dependency on PrincipalCollection
private static boolean isEmpty(Collection c) {
return c == null || c.isEmpty();
}
}