org.apache.log4j.xml.Log4jEntityResolver Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.log4j.xml;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.Constants;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
/**
* An {@link EntityResolver} specifically designed to return
* log4j.dtd which is embedded within the log4j jar
* file.
*/
public class Log4jEntityResolver implements EntityResolver {
private static final Logger LOGGER = StatusLogger.getLogger();
private static final String PUBLIC_ID = "-//APACHE//DTD LOG4J 1.2//EN";
@Override
public InputSource resolveEntity(String publicId, String systemId) {
if (systemId.endsWith("log4j.dtd") || PUBLIC_ID.equals(publicId)) {
Class clazz = getClass();
InputStream in = clazz.getResourceAsStream("/org/apache/log4j/xml/log4j.dtd");
if (in == null) {
LOGGER.warn("Could not find [log4j.dtd] using [{}] class loader, parsed without DTD.",
clazz.getClassLoader());
in = new ByteArrayInputStream(Constants.EMPTY_BYTE_ARRAY);
}
return new InputSource(in);
}
return null;
}
}