Java tutorial
/* * ==================================================================== * 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.http.impl.client.cache; import java.io.IOException; import java.util.LinkedHashMap; import org.apache.http.annotation.ThreadSafe; import org.apache.http.client.cache.HttpCacheEntry; import org.apache.http.client.cache.HttpCacheStorage; import org.apache.http.client.cache.HttpCacheUpdateCallback; /** * Basic {@link HttpCacheStorage} implementation backed by an instance of * {@link LinkedHashMap}. In other words, cache entries and the cached * response bodies are held in-memory. This cache does NOT deallocate * resources associated with the cache entries; it is intended for use * with {@link HeapResource} and similar. This is the default cache * storage backend used by {@link CachingHttpClient}. * * @since 4.1 */ @ThreadSafe public class BasicHttpCacheStorage implements HttpCacheStorage { private final CacheMap entries; public BasicHttpCacheStorage(CacheConfig config) { super(); this.entries = new CacheMap(config.getMaxCacheEntries()); } /** * Places a HttpCacheEntry in the cache * * @param url * Url to use as the cache key * @param entry * HttpCacheEntry to place in the cache */ public synchronized void putEntry(String url, HttpCacheEntry entry) throws IOException { entries.put(url, entry); } /** * Gets an entry from the cache, if it exists * * @param url * Url that is the cache key * @return HttpCacheEntry if one exists, or null for cache miss */ public synchronized HttpCacheEntry getEntry(String url) throws IOException { return entries.get(url); } /** * Removes a HttpCacheEntry from the cache * * @param url * Url that is the cache key */ public synchronized void removeEntry(String url) throws IOException { entries.remove(url); } public synchronized void updateEntry(String url, HttpCacheUpdateCallback callback) throws IOException { HttpCacheEntry existingEntry = entries.get(url); entries.put(url, callback.update(existingEntry)); } }