/*
* ====================================================================
* 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.io;
import java.io.
IOException;
import java.io.
OutputStream;
import org.apache.http.io.
SessionOutputBuffer;
/**
* Implements chunked transfer coding. The content is sent in small chunks.
* Entities transferred using this output stream can be of unlimited length.
* Writes are buffered to an internal buffer (2048 default size).
* <p>
* Note that this class NEVER closes the underlying stream, even when close
* gets called. Instead, the stream will be marked as closed and no further
* output will be permitted.
*
*
* @since 4.0
*/
public class
ChunkedOutputStream extends
OutputStream {
// ----------------------------------------------------- Instance Variables
private final
SessionOutputBuffer out;
private final byte[]
cache;
private int
cachePosition = 0;
private boolean
wroteLastChunk = false;
/** True if the stream is closed. */
private boolean
closed = false;
/**
* Wraps a session output buffer and chunk-encodes the output.
*
* @param out The session output buffer
* @param bufferSize The minimum chunk size (excluding last chunk)
* @throws IOException not thrown
*
* @deprecated (4.3) use {@link ChunkedOutputStream#ChunkedOutputStream(int, SessionOutputBuffer)}
*/
@
Deprecated
public
ChunkedOutputStream(final
SessionOutputBuffer out, final int
bufferSize)
throws
IOException {
this(
bufferSize,
out);
}
/**
* Wraps a session output buffer and chunks the output. The default buffer
* size of 2048 was chosen because the chunk overhead is less than 0.5%
*
* @param out the output buffer to wrap
* @throws IOException not thrown
*
* @deprecated (4.3) use {@link ChunkedOutputStream#ChunkedOutputStream(int, SessionOutputBuffer)}
*/
@
Deprecated
public
ChunkedOutputStream(final
SessionOutputBuffer out)
throws
IOException {
this(2048,
out);
}
/**
* Wraps a session output buffer and chunk-encodes the output.
*
* @param bufferSize The minimum chunk size (excluding last chunk)
* @param out The session output buffer
*/
public
ChunkedOutputStream(final int
bufferSize, final
SessionOutputBuffer out) {
super();
this.
cache = new byte[
bufferSize];
this.
out =
out;
}
/**
* Writes the cache out onto the underlying stream
*/
protected void
flushCache() throws
IOException {
if (this.
cachePosition > 0) {
this.
out.
writeLine(
Integer.
toHexString(this.
cachePosition));
this.
out.
write(this.
cache, 0, this.
cachePosition);
this.
out.
writeLine("");
this.
cachePosition = 0;
}
}
/**
* Writes the cache and bufferToAppend to the underlying stream
* as one large chunk
*/
protected void
flushCacheWithAppend(final byte
bufferToAppend[], final int
off, final int
len) throws
IOException {
this.
out.
writeLine(
Integer.
toHexString(this.
cachePosition +
len));
this.
out.
write(this.
cache, 0, this.
cachePosition);
this.
out.
write(
bufferToAppend,
off,
len);
this.
out.
writeLine("");
this.
cachePosition = 0;
}
protected void
writeClosingChunk() throws
IOException {
// Write the final chunk.
this.
out.
writeLine("0");
this.
out.
writeLine("");
}
// ----------------------------------------------------------- Public Methods
/**
* Must be called to ensure the internal cache is flushed and the closing
* chunk is written.
* @throws IOException in case of an I/O error
*/
public void
finish() throws
IOException {
if (!this.
wroteLastChunk) {
flushCache();
writeClosingChunk();
this.
wroteLastChunk = true;
}
}
// -------------------------------------------- OutputStream Methods
@
Override
public void
write(final int
b) throws
IOException {
if (this.
closed) {
throw new
IOException("Attempted write to closed stream.");
}
this.
cache[this.
cachePosition] = (byte)
b;
this.
cachePosition++;
if (this.
cachePosition == this.
cache.length) {
flushCache();
}
}
/**
* Writes the array. If the array does not fit within the buffer, it is
* not split, but rather written out as one large chunk.
*/
@
Override
public void
write(final byte
b[]) throws
IOException {
write(
b, 0,
b.length);
}
/**
* Writes the array. If the array does not fit within the buffer, it is
* not split, but rather written out as one large chunk.
*/
@
Override
public void
write(final byte
src[], final int
off, final int
len) throws
IOException {
if (this.
closed) {
throw new
IOException("Attempted write to closed stream.");
}
if (
len >= this.
cache.length - this.
cachePosition) {
flushCacheWithAppend(
src,
off,
len);
} else {
System.
arraycopy(
src,
off,
cache, this.
cachePosition,
len);
this.
cachePosition +=
len;
}
}
/**
* Flushes the content buffer and the underlying stream.
*/
@
Override
public void
flush() throws
IOException {
flushCache();
this.
out.
flush();
}
/**
* Finishes writing to the underlying stream, but does NOT close the underlying stream.
*/
@
Override
public void
close() throws
IOException {
if (!this.
closed) {
this.
closed = true;
finish();
this.
out.
flush();
}
}
}