/* SAXEntityResolver.java NanoXML/SAX
*
* $Revision: 1.4 $
* $Date: 2002/01/04 21:03:28 $
* $Name: RELEASE_2_2_1 $
*
* This file is part of the SAX adapter for NanoXML 2 for Java.
* Copyright (C) 2000-2002 Marc De Scheemaecker, All Rights Reserved.
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from the
* use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in
* a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*/
package edu.isi.karma.modeling.research.graphmatching.net.n3.nanoxml.sax;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import edu.isi.karma.modeling.research.graphmatching.net.n3.nanoxml.IXMLReader;
import edu.isi.karma.modeling.research.graphmatching.net.n3.nanoxml.XMLEntityResolver;
/**
* SAXEntityResolver is a subclass of XMLEntityResolver that supports the
* SAX EntityResolver listener.
*
* @see net.n3.nanoxml.IXMLEntityResolver
*
* @author Marc De Scheemaecker
* @version $Name: RELEASE_2_2_1 $, $Revision: 1.4 $
*/
public class SAXEntityResolver
extends XMLEntityResolver
{
/**
* The SAX EntityResolver listener.
*/
private EntityResolver saxEntityResolver;
/**
* Creates the resolver.
*/
public SAXEntityResolver()
{
this.saxEntityResolver = null;
}
/**
* Cleans up the object when it's destroyed.
*/
protected void finalize()
throws Throwable
{
this.saxEntityResolver = null;
super.finalize();
}
/**
* Sets the SAX EntityResolver listener.
*
* @param resolver the entity resolver
*/
public void setEntityResolver(EntityResolver resolver)
{
this.saxEntityResolver = resolver;
}
/**
* Opens an external entity.
*
* @param xmlReader the current XML reader
* @param publicID the public ID, which may be null
* @param systemID the system ID
*
* @return the reader, or null if the reader could not be created/opened
*/
protected Reader openExternalEntity(IXMLReader xmlReader,
String publicID,
String systemID)
{
try {
URL url = new URL(xmlReader.getSystemID());
url = new URL(url, systemID);
if (this.saxEntityResolver != null) {
InputSource source
= this.saxEntityResolver
.resolveEntity(publicID, url.toString());
if (source != null) {
Reader reader = source.getCharacterStream();
if (reader != null) {
return reader;
}
InputStream stream = source.getByteStream();
if (stream == null) {
publicID = source.getPublicId();
systemID = source.getSystemId();
} else {
String encoding = source.getEncoding();
if (encoding != null) {
return new InputStreamReader(stream, encoding);
} else { // if encoding == null
return new InputStreamReader(stream);
}
}
}
}
return super.openExternalEntity(xmlReader, publicID, systemID);
} catch (Exception e) {
return null;
}
}
}