/*

  * Copyright 2007 The Kuali Foundation

  * 

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  * 

  * 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.kuali.rice.ken.util;

 import java.io.IOException;

 import java.io.InputStream;

 import org.xml.sax.EntityResolver;

 import org.xml.sax.InputSource;

 import org.xml.sax.SAXException;

 /**

  * Internal notification EntityResolver which resolves system ids with the "resource:" prefix to ClassLoader resources

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class ClassLoaderEntityResolver extends ClassLoaderResourceResolver implements EntityResolver {

     /**

      * Constructs a ClassLoaderEntityResolver.java.

      */

     public ClassLoaderEntityResolver() {

         super();

     }

     /**

      * Constructs a ClassLoaderEntityResolver.java.

      * @param base

      * @param prefix

      */

     public ClassLoaderEntityResolver(String base, String prefix) {

         super(base, prefix);

     }

     /**

      * @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String, java.lang.String)

      */

     public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException {

         LOG.debug("Resolving '" + publicId + "' / '" + systemId + "'");

         String path = resolveSystemId(systemId);

         if (path == null) {

             LOG.error("Unable to resolve system id '" + systemId + "' locally...delegating to default resolution strategy.");

             return null;

         }

         LOG.debug("Looking up resource '" + path + "' for entity '" + systemId + "'");

         InputStream is = getClass().getClassLoader().getResourceAsStream(path);

         if (is == null) {

             String message = "Unable to find schema (" + path + ") for: " + systemId;

             LOG.warn(message);

             // necessary if processContents is lax, because lax doesn't care...if it doesn't resolve it won't validate

             // (not quite clear, as lax could be interpreted as *if the namespace is valid*, treating a present, but invalid

             // namespace as a fatal error. instead, apparently a present but invalid namespace is ignored with 'lax'

             // so w should use strict to ensure that is an error instead of throwing an exception here gratuitously

             // which will screw up compound resolution

             //throw new SAXException(message);

             return null;

         }

         return new InputSource(is);

     }

     /**

      * @see java.lang.Object#toString()

      */

     public String toString() {

         return "[ClassLoaderEntityResolver: base=" + base + ", prefix=" + prefix + "]";

     }

 }