com.google.common.cache.ForwardingCache Maven / Gradle / Ivy
/*
* Copyright (C) 2011 The Guava 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 com.google.common.cache;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Preconditions;
import com.google.common.collect.ForwardingObject;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import javax.annotation.CheckForNull;
/**
* A cache which forwards all its method calls to another cache. Subclasses should override one or
* more methods to modify the behavior of the backing cache as desired per the decorator pattern.
*
* @author Charles Fry
* @since 10.0
*/
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingCache extends ForwardingObject implements Cache {
/** Constructor for use by subclasses. */
protected ForwardingCache() {}
@Override
protected abstract Cache delegate();
/** @since 11.0 */
@Override
@CheckForNull
public V getIfPresent(Object key) {
return delegate().getIfPresent(key);
}
/** @since 11.0 */
@Override
public V get(K key, Callable valueLoader) throws ExecutionException {
return delegate().get(key, valueLoader);
}
/** @since 11.0 */
@Override
/*
* is mostly the same as to plain Java. But to nullness checkers, they
* differ: means "non-null types," while means "all types."
*/
public ImmutableMap getAllPresent(Iterable keys) {
return delegate().getAllPresent(keys);
}
/** @since 11.0 */
@Override
public void put(K key, V value) {
delegate().put(key, value);
}
/** @since 12.0 */
@Override
public void putAll(Map m) {
delegate().putAll(m);
}
@Override
public void invalidate(Object key) {
delegate().invalidate(key);
}
/** @since 11.0 */
@Override
// For discussion of , see getAllPresent.
public void invalidateAll(Iterable keys) {
delegate().invalidateAll(keys);
}
@Override
public void invalidateAll() {
delegate().invalidateAll();
}
@Override
public long size() {
return delegate().size();
}
@Override
public CacheStats stats() {
return delegate().stats();
}
@Override
public ConcurrentMap asMap() {
return delegate().asMap();
}
@Override
public void cleanUp() {
delegate().cleanUp();
}
/**
* A simplified version of {@link ForwardingCache} where subclasses can pass in an already
* constructed {@link Cache} as the delegate.
*
* @since 10.0
*/
public abstract static class SimpleForwardingCache extends ForwardingCache {
private final Cache delegate;
protected SimpleForwardingCache(Cache delegate) {
this.delegate = Preconditions.checkNotNull(delegate);
}
@Override
protected final Cache delegate() {
return delegate;
}
}
}