/*
* $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/AutoCloseInputStream.java,v 1.7 2003/01/28 04:40:20 jsdever Exp $
* $Revision: 1.7 $
* $Date: 2003/01/28 04:40:20 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* 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
* .
*
* [Additional notices, if required by prior licensing conditions]
*
*/
package org.apache.commons.httpclient;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* Closes an underlying stream as soon as the end of the stream is reached, and
* notifies a client when it has done so.
*
* @author Ortwin Glück
* @author Eric Johnson
* @author Mike Bowler
*
* @since 2.0
*/
class AutoCloseInputStream extends FilterInputStream {
/**
* True if this stream is open. Assume that the underlying stream
* is open until we get an EOF indication.
*/
private boolean streamOpen = true;
/** True if the stream closed itself. */
private boolean selfClosed = false;
/**
* The watcher is notified when the contents of the stream have
* been exhausted
*/
private ResponseConsumedWatcher watcher = null;
/**
* Create a new auto closing stream for the provided connection
*
* @param in the input stream to read from
* @param watcher To be notified when the contents of the stream have been
* consumed.
*/
public AutoCloseInputStream(
final InputStream in, final ResponseConsumedWatcher watcher) {
super(in);
this.watcher = watcher;
}
/**
* Reads the next byte of data from the input stream.
*
* @throws IOException when there is an error reading
* @return the character read, or -1 for EOF
*/
public int read() throws IOException {
int l = -1;
if (isReadAllowed()) {
// underlying stream not closed, go ahead and read.
l = super.read();
checkClose(l);
}
return l;
}
/**
* Reads up to len bytes of data from the stream.
*
* @param b a byte array to read data into
* @param off an offset within the array to store data
* @param len the maximum number of bytes to read
* @return the number of bytes read or -1 for EOF
* @throws IOException if there are errors reading
*/
public int read(byte[] b, int off, int len) throws IOException {
int l = -1;
if (isReadAllowed()) {
l = super.read(b, off, len);
checkClose(l);
}
return l;
}
/**
* Reads some number of bytes from the input stream and stores them into the
* buffer array b.
*
* @param b a byte array to read data into
* @return the number of bytes read or -1 for EOF
* @throws IOException if there are errors reading
*/
public int read(byte[] b) throws IOException {
int l = -1;
if (isReadAllowed()) {
l = super.read(b);
checkClose(l);
}
return l;
}
/**
* Close the stream, and also close the underlying stream if it is not
* already closed.
* @throws IOException If an IO problem occurs.
*/
public void close() throws IOException {
if (!selfClosed) {
selfClosed = true;
notifyWatcher();
}
}
/**
* Close the underlying stream should the end of the stream arrive.
*
* @param readResult The result of the read operation to check.
* @throws IOException If an IO problem occurs.
*/
private void checkClose(int readResult) throws IOException {
if (readResult == -1) {
notifyWatcher();
}
}
/**
* See whether a read of the underlying stream should be allowed, and if
* not, check to see whether our stream has already been closed!
*
* @return true if it is still OK to read from the stream.
* @throws IOException If an IO problem occurs.
*/
private boolean isReadAllowed() throws IOException {
if (!streamOpen && selfClosed) {
throw new IOException("Attempted read on closed stream.");
}
return streamOpen;
}
/**
* Notify the watcher that the contents have been consumed.
* @throws IOException If an IO problem occurs.
*/
private void notifyWatcher() throws IOException {
if (streamOpen) {
super.close();
streamOpen = false;
if (watcher != null) {
watcher.responseConsumed();
}
}
}
}
