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/*
* Enhydra Java Application Server Project
*
* The contents of this file are subject to the Enhydra Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License on
* the Enhydra web site ( http://www.enhydra.org/ ).
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific terms governing rights and limitations
* under the License.
*
* The Initial Developer of the Enhydra Application Server is Lutris
* Technologies, Inc. The Enhydra Application Server and portions created
* by Lutris Technologies, Inc. are Copyright Lutris Technologies, Inc.
* All Rights Reserved.
*
* Contributor(s):
*
* $Id: ClosingInputSource.java,v 1.2 2005/01/26 08:29:24 jkjome Exp $
*/
package org.enhydra.xml.io;
import java.io.FilterInputStream;
import java.io.FilterReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import org.xml.sax.InputSource;
/**
* Input source that automatically close its InputStream when EOF is reached
* or an error occurs. This works around a flaw in the SAX API where there is
* not method of an entity handler that opens a stream to be informed when the
* stream is no longer needed.
*/
public class ClosingInputSource extends InputSource {
/**
* InputStream that closes on EOF or read error.
*/
private class ClosingInputStream extends FilterInputStream {
/**
* Constructor
*/
public ClosingInputStream(InputStream stream) {
super(stream);
}
/**
* Read a byte from the stream.
*/
public int read() throws IOException {
try {
int bt = super.read();
if (bt < 0) {
close();
}
return bt;
} catch (IOException except) {
close();
throw except;
}
}
/**
* Read bytes from the stream.
*/
public int read(byte[] bBuf, int off, int len) throws IOException {
try {
int readLen = super.read(bBuf, off, len);
if (readLen < 0) {
close();
}
return readLen;
} catch (IOException except) {
close();
throw except;
}
}
}
/**
* Reader that closes on EOF or read error.
*/
private class ClosingReader extends FilterReader {
/**
* Constructor
*/
public ClosingReader(Reader stream) {
super(stream);
}
/**
* Read a character from the stream.
*/
public int read() throws IOException {
try {
int ch = super.read();
if (ch < 0) {
close();
}
return ch;
} catch (IOException except) {
close();
throw except;
}
}
/**
* Read characters from the stream.
*/
public int read(char[] cBuf, int off, int len) throws IOException {
try {
int readLen = super.read(cBuf, off, len);
if (readLen < 0) {
close();
}
return readLen;
} catch (IOException except) {
close();
throw except;
}
}
}
/**
* If the resource is specified by system id, open it now as a byte
* stream. If the resource is specified by byte or character stream, this
* does nothing.
*/
public void open() throws IOException {
if ((getByteStream() == null) && (getCharacterStream() == null)) {
String systemId = getSystemId();
if (systemId == null) {
throw new IOException("systemId is not set");
}
setByteStream(InputSourceOps.openSystemId(systemId));
}
}
/**
* Zero-argument default constructor.
* @see InputSource#InputSource
*/
public ClosingInputSource() {
super();
}
/**
* Create a new input source from another input source.
*
* @param inputSource Input source specification to clone
* @param openNow If true, the input source is opened immediatly
* if specified as a system id.
* @see InputSource
*/
public ClosingInputSource(InputSource inputSource,
boolean openNow) throws IOException {
if (inputSource.getByteStream() != null) {
super.setByteStream(new ClosingInputStream(inputSource.getByteStream()));
} else if (inputSource.getCharacterStream() != null) {
super.setCharacterStream(new ClosingReader(inputSource.getCharacterStream()));
} else if (inputSource.getSystemId() != null) {
super.setSystemId(inputSource.getSystemId());
if (openNow) {
open();
}
} else {
throw new IOException("InputSource does not specify an external source of input");
}
// Fill in public and system ids and encoding
if (inputSource.getPublicId() != null) {
super.setPublicId(inputSource.getPublicId());
}
if (inputSource.getSystemId() != null) {
super.setSystemId(inputSource.getSystemId());
}
}
/**
* Create a new input source with a system identifier.
*
* @param systemId The system identifier.
* @see InputSource#InputSource(String)
*/
public ClosingInputSource(String systemId) {
super(systemId);
}
/**
* Create a new input source with a system identifier.
*
* @param systemId The system identifier.
* @param openNow If true, the input source is opened immediatly
* if specified as a system id.
* @exception IOException If an error occures opening the stream.
* @see InputSource#InputSource(String)
*/
public ClosingInputSource(String systemId,
boolean openNow) throws IOException {
super(systemId);
if (openNow) {
open();
}
}
/**
* Create a new input source with a byte stream.
* @see InputSource#InputSource(InputStream)
*/
public ClosingInputSource(InputStream byteStream) {
super();
setByteStream(byteStream);
}
/**
* Create a new input source with a character stream.
* @see InputSource#InputSource(Reader)
*/
public ClosingInputSource(Reader characterStream) {
super();
setCharacterStream(characterStream);
}
/**
* Set the byte stream, copying it to a buffer.
* @see InputSource#setByteStream
*/
public void setByteStream(InputStream byteStream) {
super.setByteStream(new ClosingInputStream(byteStream));
}
/**
* Set the character stream, copying it to a buffer.
* @see InputSource#setCharacterStream
*/
public void setCharacterStream(Reader characterStream) {
super.setCharacterStream(new ClosingReader(characterStream));
}
}
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