Commons IO example source code file (AutoCloseInputStream.java)

This example Commons IO source code file (AutoCloseInputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons IO tags/keywords

autocloseinputstream, autocloseinputstream, closedinputstream, closedinputstream, io, ioexception, ioexception, override, override, proxyinputstream, throwable

The Commons IO AutoCloseInputStream.java source code

/*
 * 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.
 */
package org.apache.commons.io.input;

import java.io.IOException;
import java.io.InputStream;

/**
 * Proxy stream that closes and discards the underlying stream as soon as the
 * end of input has been reached or when the stream is explicitly closed.
 * Not even a reference to the underlying stream is kept after it has been
 * closed, so any allocated in-memory buffers can be freed even if the
 * client application still keeps a reference to the proxy stream.
 * <p>
 * This class is typically used to release any resources related to an open
 * stream as soon as possible even if the client application (by not explicitly
 * closing the stream when no longer needed) or the underlying stream (by not
 * releasing resources once the last byte has been read) do not do that.
 *
 * @version $Id: AutoCloseInputStream.java 1003647 2010-10-01 20:53:59Z niallp $
 * @since Commons IO 1.4
 */
public class AutoCloseInputStream extends ProxyInputStream {

    /**
     * Creates an automatically closing proxy for the given input stream.
     *
     * @param in underlying input stream
     */
    public AutoCloseInputStream(InputStream in) {
        super(in);
    }

    /**
     * Closes the underlying input stream and replaces the reference to it
     * with a {@link ClosedInputStream} instance.
     * <p>
     * This method is automatically called by the read methods when the end
     * of input has been reached.
     * <p>
     * Note that it is safe to call this method any number of times. The original
     * underlying input stream is closed and discarded only once when this
     * method is first called.
     *
     * @throws IOException if the underlying input stream can not be closed
     */
    @Override
    public void close() throws IOException {
        in.close();
        in = new ClosedInputStream();
    }

    /**
     * Automatically closes the stream if the end of stream was reached.
     *
     * @param n number of bytes read, or -1 if no more bytes are available
     * @throws IOException if the stream could not be closed
     * @since Commons IO 2.0
     */
    @Override
    protected void afterRead(int n) throws IOException {
        if (n == -1) {
            close();
        }
    }

    /**
     * Ensures that the stream is closed before it gets garbage-collected.
     * As mentioned in {@link #close()}, this is a no-op if the stream has
     * already been closed.
     * @throws Throwable if an error occurs
     */
    @Override
    protected void finalize() throws Throwable {
        close();
        super.finalize();
    }

}