/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/AutoCloseInputStream.java,v 1.9 2004/04/18 23:51:34 jsdever Exp $
* $Revision: 505890 $
* $Date: 2007-02-11 12:25:25 +0100 (Sun, 11 Feb 2007) $
*
* ====================================================================
*
* 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.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 Glueck
* @author Eric Johnson
* @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
*
* @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 <code>len</code> bytes of data from the stream.
*
* @param b a <code>byte</code> 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 <code>byte</code> 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;
}
/**
* Obtains the number of bytes that can be read without blocking.
*
* @return the number of bytes available without blocking
* @throws IOException in case of a problem
*/
public int available() throws IOException {
int a = 0; // not -1
if (isReadAllowed()) {
a = super.available();
// no checkClose() here, available() can't trigger EOF
}
return a;
}
/**
* 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 <code>true</code> 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();
}
}
}
}