/**
* Copyright 2014 55 Minutes (http://www.55minutes.com)
*
* Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
*
* 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 fiftyfive.wicket.test.dtd;
import java.io.InputStream;
import java.io.IOException;
import org.apache.wicket.util.string.Strings;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Resolves XHTML entities by using locally installed DTDs. This means that
* any www.w3.org DTD will be loaded from the filesystem instead of making
* an HTTP request. This greatly improves the speed of the parser
* when validating XHTML documents.
*/
public class XHtmlEntityResolver implements EntityResolver
{
/**
* Resolves an entity using locally installed DTDs if possible.
* Otherwise returns <code>null</code> to delegate to the default
* resolver.
*/
public InputSource resolveEntity(String publicId, String systemId)
throws SAXException, IOException
{
InputSource src = null;
if(systemId.startsWith("http://www.w3.org/"))
{
InputStream in = getClass().getResourceAsStream(filename(systemId));
if(null == in)
{
onNotFound(publicId, systemId);
}
else
{
src = new InputSource(systemId);
src.setPublicId(publicId);
src.setByteStream(in);
}
}
return src;
}
/**
* This method is called when a w3 entity cannot be found on the local
* filesystem. Default implementation does nothing. This is a hook for
* testing purposes.
*/
protected void onNotFound(String publicId, String systemId)
{
// pass
}
private String filename(String systemId)
{
return Strings.lastPathComponent(systemId, '/');
}
}