/*
- * Copyright 2005 the original author or authors.
- *
+ * Copyright 2005-2010 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.wamblee.cache;
import org.apache.log4j.Logger;
import java.io.Serializable;
-
/**
- * Represents a cached object. The object is either retrieved from the
- * cache if the cache has it, or a call back is invoked to get the object (and
- * put it in the cache).
- *
+ * Represents a cached object. The object is either retrieved from the cache if
+ * the cache has it, or a call back is invoked to get the object (and put it in
+ * the cache).
+ *
* @author Erik Brakkee
- *
- * @param <KeyType> DOCUMENT ME!
- * @param <ValueType> DOCUMENT ME!
+ *
*/
public class CachedObject<KeyType extends Serializable, ValueType extends Serializable> {
- /**
- * DOCUMENT ME!
- */
private static final Logger LOGGER = Logger.getLogger(CachedObject.class);
/**
private KeyType objectKey;
/**
- * Computation used to obtain the object if it is not found in the
- * cache.
+ * Computation used to obtain the object if it is not found in the cache.
*/
private Computation<KeyType, ValueType> computation;
-/**
+ /**
* Constructs the cached object.
- *
+ *
* @param aCache
* Cache to use.
* @param aObjectKey
*/
public CachedObject(Cache<KeyType, ValueType> aCache, KeyType aObjectKey,
Computation<KeyType, ValueType> aComputation) {
- cache = aCache;
- objectKey = aObjectKey;
- computation = aComputation;
+ cache = aCache;
+ objectKey = aObjectKey;
+ computation = aComputation;
}
/**
- * Gets the object. Since the object is cached, different calls to
- * this method may return different objects.
- *
+ * Gets the object. Since the object is cached, different calls to this
+ * method may return different objects.
+ *
* @return Object.
*/
public ValueType get() {
ValueType object = (ValueType) cache.get(objectKey); // the used
- // cache is
- // thread safe.
+ // cache is
+ // thread safe.
if (object == null) {
// synchronize the computation to make sure that the object is only
}
/**
- * Invalidates the cache for the object so that it is recomputed
- * the next time it is requested.
+ * Invalidates the cache for the object so that it is recomputed the next
+ * time it is requested.
*/
public void invalidate() {
cache.remove(objectKey);
/**
* Gets the cache.
- *
+ *
* @return Cache.
*/
public Cache getCache() {
return cache;
}
-/**
+ /**
* Callback invoked to compute an object if it was not found in the cache.
- *
+ *
* @param <T>
* Type of the object
*/
public static interface Computation<Key extends Serializable, Value extends Serializable> {
/**
- * Gets the object. Called when the object is not in the
- * cache.
- *
- * @param aObjectKey Id of the object in the cache.
- *
+ * Gets the object. Called when the object is not in the cache.
+ *
+ * @param aObjectKey
+ * Id of the object in the cache.
+ *
* @return Object, must be non-null.
*/
Value getObject(Key aObjectKey);