//$Id: DTDEntityResolver.java 10033 2006-06-21 06:23:30Z [email protected] $
//Contributed by Markus Meissner
package org.hibernate.util;
import java.io.InputStream;
import java.io.Serializable;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
/**
* An {@link EntityResolver} implementation which attempts to resolve
* various systemId URLs to local classpath lookups<ol>
* <li>Any systemId URL beginning with <tt>http://hibernate.sourceforge.net/</tt> is
* searched for as a classpath resource in the classloader which loaded the
* Hibernate classes.</li>
* <li>Any systemId URL using <tt>classpath</tt> as the scheme (i.e. starting
* with <tt>classpath://</tt> is searched for as a classpath resource using first
* the current thread context classloader and then the classloader which loaded
* the Hibernate classes.
* </ol>
* <p/>
* Any entity references which cannot be resolved in relation to the above
* rules result in returning null, which should force the SAX reader to
* handle the entity reference in its default manner.
*/
public class DTDEntityResolver implements EntityResolver, Serializable {
private static final Log log = LogFactory.getLog( DTDEntityResolver.class );
private static final String HIBERNATE_NAMESPACE = "http://hibernate.sourceforge.net/";
private static final String USER_NAMESPACE = "classpath://";
public InputSource resolveEntity(String publicId, String systemId) {
if ( systemId != null ) {
log.debug( "trying to resolve system-id [" + systemId + "]" );
if ( systemId.startsWith( HIBERNATE_NAMESPACE ) ) {
log.debug( "recognized hibernate namespace; attempting to resolve on classpath under org/hibernate/" );
String path = "org/hibernate/" + systemId.substring( HIBERNATE_NAMESPACE.length() );
InputStream dtdStream = resolveInHibernateNamespace( path );
if ( dtdStream == null ) {
log.debug( "unable to locate [" + systemId + "] on classpath" );
if ( systemId.substring( HIBERNATE_NAMESPACE.length() ).indexOf( "2.0" ) > -1 ) {
log.error( "Don't use old DTDs, read the Hibernate 3.x Migration Guide!" );
}
}
else {
log.debug( "located [" + systemId + "] in classpath" );
InputSource source = new InputSource( dtdStream );
source.setPublicId( publicId );
source.setSystemId( systemId );
return source;
}
}
else if ( systemId.startsWith( USER_NAMESPACE ) ) {
log.debug( "recognized local namespace; attempting to resolve on classpath" );
String path = systemId.substring( USER_NAMESPACE.length() );
InputStream stream = resolveInLocalNamespace( path );
if ( stream == null ) {
log.debug( "unable to locate [" + systemId + "] on classpath" );
}
else {
log.debug( "located [" + systemId + "] in classpath" );
InputSource source = new InputSource( stream );
source.setPublicId( publicId );
source.setSystemId( systemId );
return source;
}
}
}
// use default behavior
return null;
}
protected InputStream resolveInHibernateNamespace(String path) {
return this.getClass().getClassLoader().getResourceAsStream( path );
}
protected InputStream resolveInLocalNamespace(String path) {
try {
return ConfigHelper.getUserResourceAsStream( path );
}
catch( Throwable t ) {
return null;
}
}
}
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