org.springframework.cache.ehcache.EhCacheCache Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* 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.springframework.cache.ehcache;
import java.util.concurrent.Callable;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import net.sf.ehcache.Status;
import org.springframework.cache.Cache;
import org.springframework.cache.support.SimpleValueWrapper;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* {@link Cache} implementation on top of an {@link Ehcache} instance.
*
* @author Costin Leau
* @author Juergen Hoeller
* @author Stephane Nicoll
* @since 3.1
*/
public class EhCacheCache implements Cache {
private final Ehcache cache;
/**
* Create an {@link EhCacheCache} instance.
* @param ehcache the backing Ehcache instance
*/
public EhCacheCache(Ehcache ehcache) {
Assert.notNull(ehcache, "Ehcache must not be null");
Status status = ehcache.getStatus();
if (!Status.STATUS_ALIVE.equals(status)) {
throw new IllegalArgumentException(
"An 'alive' Ehcache is required - current cache is " + status.toString());
}
this.cache = ehcache;
}
@Override
public final String getName() {
return this.cache.getName();
}
@Override
public final Ehcache getNativeCache() {
return this.cache;
}
@Override
@Nullable
public ValueWrapper get(Object key) {
Element element = lookup(key);
return toValueWrapper(element);
}
@SuppressWarnings("unchecked")
@Override
@Nullable
public T get(Object key, Callable valueLoader) {
Element element = lookup(key);
if (element != null) {
return (T) element.getObjectValue();
}
else {
this.cache.acquireWriteLockOnKey(key);
try {
element = lookup(key); // one more attempt with the write lock
if (element != null) {
return (T) element.getObjectValue();
}
else {
return loadValue(key, valueLoader);
}
}
finally {
this.cache.releaseWriteLockOnKey(key);
}
}
}
private T loadValue(Object key, Callable valueLoader) {
T value;
try {
value = valueLoader.call();
}
catch (Throwable ex) {
throw new ValueRetrievalException(key, valueLoader, ex);
}
put(key, value);
return value;
}
@Override
@SuppressWarnings("unchecked")
@Nullable
public T get(Object key, @Nullable Class type) {
Element element = this.cache.get(key);
Object value = (element != null ? element.getObjectValue() : null);
if (value != null && type != null && !type.isInstance(value)) {
throw new IllegalStateException(
"Cached value is not of required type [" + type.getName() + "]: " + value);
}
return (T) value;
}
@Override
public void put(Object key, @Nullable Object value) {
this.cache.put(new Element(key, value));
}
@Override
@Nullable
public ValueWrapper putIfAbsent(Object key, @Nullable Object value) {
Element existingElement = this.cache.putIfAbsent(new Element(key, value));
return toValueWrapper(existingElement);
}
@Override
public void evict(Object key) {
this.cache.remove(key);
}
@Override
public void clear() {
this.cache.removeAll();
}
@Nullable
private Element lookup(Object key) {
return this.cache.get(key);
}
@Nullable
private ValueWrapper toValueWrapper(@Nullable Element element) {
return (element != null ? new SimpleValueWrapper(element.getObjectValue()) : null);
}
}