org.apache.cocoon.util.PostInputStream Maven / Gradle / Ivy
/*
* 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.cocoon.util;
import java.io.IOException;
import java.io.InputStream;
/**
* The class PostInputStream is a wrapper for InputStream associated with POST message.
* It allows to control read operation, restricting the number of bytes read to the value returned by getContentLen() method.
*
* @version $Id: PostInputStream.java 490773 2006-12-28 19:27:50Z danielf $
*/
public class PostInputStream extends InputStream {
/**
* Class name
*/
public static final String CLASS = PostInputStream.class.getName();
/** The real InputStream object */
private InputStream m_inputStream = null;
/** The length of InputStream */
private int m_contentLen = 0;
/** The number of bytes read */
protected int m_bytesRead = 0;
/**
* Creates a PostInputStream
*/
public PostInputStream() {
super();
}
/**
* Creates a PostInputStream based on a real InputStream object with the specified
* post message body length. Saves its argument, the input stream
* m_inputStream, for later use.
*
* @param input the underlying input stream.
* @param len the post message body length.
* @exception IllegalArgumentException len <= 0.
*/
public PostInputStream(final InputStream input, final int len) throws IllegalArgumentException {
super();
init(input, len );
}
/**
* Sets the underlying input stream and contentLen value .
*
* @param input the input stream; can not be null.
* @param len the post message body length.
*
* @throws IllegalArgumentException
*/
protected void init(final InputStream input, final int len) throws IllegalArgumentException {
if (len <= 0) {
throw new IllegalArgumentException("contentLen <= 0 ");
}
this.m_inputStream = input;
this.m_contentLen = len;
}
/**
* Sets the underlying input stream and contentLen value .
*
* @param input the input stream; can not be null.
* @param len the post message body length.
*
* @throws IOException
*/
public synchronized void setInputStream(final InputStream input, final int len) throws IOException {
if (m_inputStream != null) {
close();
}
init(input, len);
}
/**
* Returns the underlying input stream.
*
* @return inputStream the underlying InputStream.
*/
public InputStream getInputStream() {
return m_inputStream;
}
/**
* Returns the post message body length.
*
* @return m_contentLen;
*/
public int getContentLen() {
return( m_contentLen );
}
/**
* Reads the next byte from the input stream. If the end of the stream has been reached, this method returns -1.
*
* @return the next byte or -1 if at the end of the stream.
*
* @throws IOException
*/
public synchronized int read() throws IOException {
checkOpen();
if (m_bytesRead == m_contentLen) {
return -1;
}
int byt = m_inputStream.read();
if (byt != -1) {
m_bytesRead++;
}
return byt;
}
/**
* Reads bytes from this byte-input stream into the specified byte array,
* starting at the given offset.
*
* This method implements the general contract of the corresponding
* {@link InputStream#read(byte[], int, int) read} method of
* the {@link InputStream} class.
* This method delegetes the read operation to the underlying InputStream implementation class but it
* controlls the number of bytes read from the stream. In the remote situation the underlying InputStream has no knowledge of
* the length of the stream and the notion of the "end" is undefined. This wrapper class has a knowledge of the
* length of data send by the requestor by the means of contentLength. This method returns the number of bytes read and
* accumulates the total number of bytes read in m_bytesRead. When the m_bytesRead is equal to the specified contentLength
* value the method returns returns -1 to signal the end of data.
*
* @param buffer the byte array to read into; can not be null.
* @param offset the starting offset in the byte array.
* @param len the maximum number of bytes to read.
*
* @return the number of bytes read, or -1 if the end of
* the stream has been reached.
* @exception IOException if an I/O error occurs.
*/
public synchronized int read(byte[] buffer, int offset, int len) throws IOException {
checkOpen();
if (m_bytesRead == m_contentLen) {
return -1;
}
int available = Math.min( available(), len );
int num = m_inputStream.read( buffer, offset, available );
if (num > 0) {
m_bytesRead += num;
}
return num;
}
public synchronized int read(byte[] buffer) throws IOException {
return read( buffer, 0, buffer.length);
}
/**
* Checks to see if this stream is closed; if it is, an IOException is thrown.
*
* @throws IOException
*/
protected void checkOpen() throws IOException {
if (m_inputStream == null) {
throw new IOException("InputStream closed");
}
}
/**
* See the general contract of the skip
* method of InputStream.
* Delegates execution to the underlying InputStream implementation class.
* Checks to see if this stream is closed; if it is, an IOException is thrown.
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException if an I/O error occurs.
*/
public synchronized long skip(long n) throws IOException {
checkOpen();
if ( m_bytesRead == m_contentLen )
{
return ( 0 );
}
else
{
return ( m_inputStream.skip( n ) );
}
}
/**
* Returns the number of bytes available from this input stream that can be read without the stream blocking.
* Delegates execution to the underlying InputStream implementation class.
* @return available the number of available bytes.
*
* @throws IOException
*/
public synchronized int available() throws IOException {
checkOpen();
int avail = m_inputStream.available();
return (avail == 0 ? (m_contentLen - m_bytesRead) : avail);
}
/**
* Tests if this input stream supports the mark
* and reset methods. The markSupported
* method of BufferedInputStream returns
* false.
*
* @return a boolean indicating if this stream type supports
* the mark and reset methods.
* @see java.io.InputStream#mark(int)
* @see java.io.InputStream#reset()
*/
public boolean markSupported() {
return false;
}
/**
* Closes this input stream by closing the underlying stream and marking this one as closed.
*
* @throws IOException
*/
public synchronized void close() throws IOException {
if (m_inputStream == null) {
return;
}
m_inputStream.close();
m_inputStream = null;
m_contentLen = 0;
m_bytesRead = 0;
}
/**
* Returns a String representation of this.
*
* @return string the String representation of this.
*/
public String toString() {
return new StringBuffer(getClass().getName())
.append("[inputStream=").append(m_inputStream)
.append(", contentLen=").append(m_contentLen)
.append("bytesRead=").append(m_bytesRead)
.append("]").toString();
}
}