[jboss-cvs] jboss-seam/src/main/org/jboss/seam/util ...

[Gavin King]

  User: gavin   
  Date: 06/11/10 14:07:01

  Added:       src/main/org/jboss/seam/util  DTDEntityResolver.java
  Log:
  add DTDs for seam config files
  
  Revision  Changes    Path
  1.1      date: 2006/11/10 19:07:01;  author: gavin;  state: Exp;jboss-seam/src/main/org/jboss/seam/util/DTDEntityResolver.java
  
  Index: DTDEntityResolver.java
  ===================================================================
  //$Id: DTDEntityResolver.java,v 1.1 2006/11/10 19:07:01 gavin Exp $
  //Contributed by Markus Meissner
  package org.jboss.seam.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://jboss.com/products/seam/</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://jboss.com/products/seam/";
  	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/jboss/seam/" );
  				String path = "org/jboss/seam/" + 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 Resources.getResourceAsStream( path );
  		}
  		catch( Throwable t ) {
  			return null;
  		}
  	}
  }