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.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import org.apache.http.annotation.ThreadSafe; import org.apache.http.client.cache.Resource; /** * Cache resource backed by a file. * * @since 4.1 */ @ThreadSafe public class FileResource implements Resource { private static final long serialVersionUID = 4132244415919043397L; private final File file; private volatile boolean disposed; public FileResource(final File file) { super(); this.file = file; this.disposed = false; } private void ensureValid() { if (this.disposed) { throw new IllegalStateException("Resource has been deallocated"); } } synchronized File getFile() { ensureValid(); return this.file; } public synchronized InputStream getInputStream() throws IOException { ensureValid(); return new FileInputStream(this.file); } public synchronized long length() { ensureValid(); return this.file.length(); } public synchronized void dispose() { if (this.disposed) { return; } this.disposed = true; this.file.delete(); } }