/*
 * ====================================================================
 * 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();
    }

}
