/*
* 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 SF 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.sling.discovery.impl.setup;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.URL;
import org.apache.log4j.Layout;
import org.apache.log4j.LogManager;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.WriterAppender;
public class WithholdingAppender extends WriterAppender {
private final ByteArrayOutputStream baos;
private final Writer writer;
/**
* Install the WithholdingAppender, essentially muting all logging
* and withholding it until release() is called
* @return the WithholdingAppender that can be used to get the
* withheld log output
*/
public static WithholdingAppender install() {
LogManager.getRootLogger().removeAllAppenders();
final WithholdingAppender withholdingAppender = new WithholdingAppender(
new PatternLayout("%d{dd.MM.yyyy HH:mm:ss} *%-5p* [%t] %c{1}: %m\n"));
LogManager.getRootLogger().addAppender(withholdingAppender);
return withholdingAppender;
}
/**
* Release this WithholdingAppender and optionally dump what was
* withheld (eg in case of an exception)
* @param dumpToSysout
*/
public void release(boolean dumpToSysout) {
LogManager.resetConfiguration();
URL log4jPropertiesFile = getClass().getResource("/log4j.properties");
PropertyConfigurator.configure(log4jPropertiesFile);
if (dumpToSysout) {
String withheldLogoutput = getBuffer();
System.out.println(withheldLogoutput);
}
}
public WithholdingAppender(Layout layout) {
this.layout = layout;
this.baos = new ByteArrayOutputStream();
this.writer = new BufferedWriter(new OutputStreamWriter(baos));
this.setWriter(writer);
}
public String getBuffer() {
try{
writer.flush();
} catch(IOException e) {
// ignore
}
return baos.toString();
}
}