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/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/ContentLengthInputStream.java,v 1.12 2004/10/04 22:05:44 olegk Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  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
 * .
 *
 */

package org.apache.commons.httpclient;

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

/**
 * Cuts the wrapped InputStream off after a specified number of bytes.
 *
 * 

Implementation note: Choices abound. One approach would pass * through the {@link InputStream#mark} and {@link InputStream#reset} calls to * the underlying stream. That's tricky, though, because you then have to * start duplicating the work of keeping track of how much a reset rewinds. * Further, you have to watch out for the "readLimit", and since the semantics * for the readLimit leave room for differing implementations, you might get * into a lot of trouble.

* *

Alternatively, you could make this class extend {@link java.io.BufferedInputStream} * and then use the protected members of that class to avoid duplicated effort. * That solution has the side effect of adding yet another possible layer of * buffering.

* *

Then, there is the simple choice, which this takes - simply don't * support {@link InputStream#mark} and {@link InputStream#reset}. That choice * has the added benefit of keeping this class very simple.

* * @author Ortwin Glueck * @author Eric Johnson * @author Mike Bowler * @since 2.0 * @deprecated Jakarta Commons HttpClient 3.x is deprecated in the Jenkins project. * It is not recommended to use it in any new code. * Instead, use HTTP client API plugins as a dependency in your code. * E.g. * Apache HttpComponents Client API 4.x Plugin or * Async HTTP Client Plugin. */ @Deprecated public class ContentLengthInputStream extends InputStream { /** * The maximum number of bytes that can be read from the stream. Subsequent * read operations will return -1. */ private long contentLength; /** The current position */ private long pos = 0; /** True if the stream is closed. */ private boolean closed = false; /** * Wrapped input stream that all calls are delegated to. */ private InputStream wrappedStream = null; /** * @deprecated use {@link #ContentLengthInputStream(InputStream, long)} * * Creates a new length limited stream * * @param in The stream to wrap * @param contentLength The maximum number of bytes that can be read from * the stream. Subsequent read operations will return -1. */ public ContentLengthInputStream(InputStream in, int contentLength) { this(in, (long)contentLength); } /** * Creates a new length limited stream * * @param in The stream to wrap * @param contentLength The maximum number of bytes that can be read from * the stream. Subsequent read operations will return -1. * * @since 3.0 */ public ContentLengthInputStream(InputStream in, long contentLength) { super(); this.wrappedStream = in; this.contentLength = contentLength; } /** *

Reads until the end of the known length of content.

* *

Does not close the underlying socket input, but instead leaves it * primed to parse the next response.

* @throws IOException If an IO problem occurs. */ public void close() throws IOException { if (!closed) { try { ChunkedInputStream.exhaustInputStream(this); } finally { // close after above so that we don't throw an exception trying // to read after closed! closed = true; } } } /** * Read the next byte from the stream * @return The next byte or -1 if the end of stream has been reached. * @throws IOException If an IO problem occurs * @see java.io.InputStream#read() */ public int read() throws IOException { if (closed) { throw new IOException("Attempted read from closed stream."); } if (pos >= contentLength) { return -1; } pos++; return this.wrappedStream.read(); } /** * Does standard {@link InputStream#read(byte[], int, int)} behavior, but * also notifies the watcher when the contents have been consumed. * * @param b The byte array to fill. * @param off Start filling at this position. * @param len The number of bytes to attempt to read. * @return The number of bytes read, or -1 if the end of content has been * reached. * * @throws java.io.IOException Should an error occur on the wrapped stream. */ public int read (byte[] b, int off, int len) throws java.io.IOException { if (closed) { throw new IOException("Attempted read from closed stream."); } if (pos >= contentLength) { return -1; } if (pos + len > contentLength) { len = (int) (contentLength - pos); } int count = this.wrappedStream.read(b, off, len); pos += count; return count; } /** * Read more bytes from the stream. * @param b The byte array to put the new data in. * @return The number of bytes read into the buffer. * @throws IOException If an IO problem occurs * @see java.io.InputStream#read(byte[]) */ public int read(byte[] b) throws IOException { return read(b, 0, b.length); } /** * Skips and discards a number of bytes from the input stream. * @param n The number of bytes to skip. * @return The actual number of bytes skipped. <= 0 if no bytes * are skipped. * @throws IOException If an error occurs while skipping bytes. * @see InputStream#skip(long) */ public long skip(long n) throws IOException { // make sure we don't skip more bytes than are // still available long length = Math.min(n, contentLength - pos); // skip and keep track of the bytes actually skipped length = this.wrappedStream.skip(length); // only add the skipped bytes to the current position // if bytes were actually skipped if (length > 0) { pos += length; } return length; } public int available() throws IOException { if (this.closed) { return 0; } int avail = this.wrappedStream.available(); if (this.pos + avail > this.contentLength ) { avail = (int)(this.contentLength - this.pos); } return avail; } }




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