/*
* 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.pattern;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.spi.ThrowableInformation;
/**
* Outputs the ThrowableInformation portion of the LoggingEvent.
* By default, outputs the full stack trace. %throwable{none}
* or %throwable{0} suppresses the stack trace. %throwable{short}
* or %throwable{1} outputs just the first line. %throwable{n}
* will output n lines for a positive integer or drop the last
* -n lines for a negative integer.
*
* @author Paul Smith
*
*/
public class ThrowableInformationPatternConverter
extends LoggingEventPatternConverter {
/**
* Maximum lines of stack trace to output.
*/
private int maxLines = Integer.MAX_VALUE;
/**
* Private constructor.
* @param options options, may be null.
*/
private ThrowableInformationPatternConverter(
final String[] options) {
super("Throwable", "throwable");
if ((options != null) && (options.length > 0)) {
if("none".equals(options[0])) {
maxLines = 0;
} else if("short".equals(options[0])) {
maxLines = 1;
} else {
try {
maxLines = Integer.parseInt(options[0]);
} catch(NumberFormatException ex) {
maxLines = Integer.MAX_VALUE;
}
}
}
}
/**
* Gets an instance of the class.
* @param options pattern options, may be null. If first element is "short",
* only the first line of the throwable will be formatted.
* @return instance of class.
*/
public static ThrowableInformationPatternConverter newInstance(
final String[] options) {
return new ThrowableInformationPatternConverter(options);
}
/**
* {@inheritDoc}
*/
public void format(final LoggingEvent event, final StringBuffer toAppendTo) {
if (maxLines != 0) {
ThrowableInformation information = event.getThrowableInformation();
if (information != null) {
String[] stringRep = information.getThrowableStrRep();
int length = stringRep.length;
if (maxLines < 0) {
length += maxLines;
} else if (length > maxLines) {
length = maxLines;
}
for (int i = 0; i < length; i++) {
String string = stringRep[i];
toAppendTo.append(string).append("\n");
}
}
}
}
/**
* This converter obviously handles throwables.
* @return true.
*/
public boolean handlesThrowable() {
return true;
}
}