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The Apache Log4j Implementation
/*
* 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.logging.log4j.core.pattern;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.impl.ThrowableFormatOptions;
import org.apache.logging.log4j.core.layout.PatternLayout;
import org.apache.logging.log4j.core.util.StringBuilderWriter;
import org.apache.logging.log4j.util.Strings;
/**
* Outputs the Throwable portion of the LoggingEvent as a full stack trace
* unless this converter's option is 'short', where it just outputs the first line of the trace, or if
* the number of lines to print is explicitly specified.
*/
@Plugin(name = "ThrowablePatternConverter", category = PatternConverter.CATEGORY)
@ConverterKeys({ "ex", "throwable", "exception" })
public class ThrowablePatternConverter extends LogEventPatternConverter {
/**
* Lists {@link PatternFormatter}s for the suffix attribute.
*/
protected final List formatters;
private String rawOption;
private final boolean subShortOption;
private final boolean nonStandardLineSeparator;
/**
* Options.
*/
protected final ThrowableFormatOptions options;
/**
* Constructor.
* @param name Name of converter.
* @param style CSS style for output.
* @param options options, may be null.
* @deprecated Use ThrowablePatternConverter(String name, String stule, String[] options, Configuration config)
*/
@Deprecated
protected ThrowablePatternConverter(final String name, final String style, final String[] options) {
this(name, style, options, null);
}
/**
* Constructor.
* @param name Name of converter.
* @param style CSS style for output.
* @param options options, may be null.
* @param config
*/
protected ThrowablePatternConverter(final String name, final String style, final String[] options, final Configuration config) {
super(name, style);
this.options = ThrowableFormatOptions.newInstance(options);
if (options != null && options.length > 0) {
rawOption = options[0];
}
if (this.options.getSuffix() != null) {
final PatternParser parser = PatternLayout.createPatternParser(config);
final List parsedSuffixFormatters = parser.parse(this.options.getSuffix());
// filter out nested formatters that will handle throwable
boolean hasThrowableSuffixFormatter = false;
for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
if (suffixFormatter.handlesThrowable()) {
hasThrowableSuffixFormatter = true;
}
}
if (!hasThrowableSuffixFormatter) {
this.formatters = parsedSuffixFormatters;
} else {
final List suffixFormatters = new ArrayList<>();
for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
if (!suffixFormatter.handlesThrowable()) {
suffixFormatters.add(suffixFormatter);
}
}
this.formatters = suffixFormatters;
}
} else {
this.formatters = Collections.emptyList();
}
subShortOption = ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
nonStandardLineSeparator = !Strings.LINE_SEPARATOR.equals(this.options.getSeparator());
}
/**
* Gets an instance of the class.
*
* @param config
* @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 ThrowablePatternConverter newInstance(final Configuration config, final String[] options) {
return new ThrowablePatternConverter("Throwable", "throwable", options, config);
}
/**
* {@inheritDoc}
*/
@Override
public void format(final LogEvent event, final StringBuilder buffer) {
final Throwable t = event.getThrown();
if (subShortOption) {
formatSubShortOption(t, getSuffix(event), buffer);
}
else if (t != null && options.anyLines()) {
formatOption(t, getSuffix(event), buffer);
}
}
private void formatSubShortOption(final Throwable t, final String suffix, final StringBuilder buffer) {
StackTraceElement[] trace;
StackTraceElement throwingMethod = null;
int len;
if (t != null) {
trace = t.getStackTrace();
if (trace !=null && trace.length > 0) {
throwingMethod = trace[0];
}
}
if (t != null && throwingMethod != null) {
String toAppend = Strings.EMPTY;
if (ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption)) {
toAppend = throwingMethod.getClassName();
}
else if (ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption)) {
toAppend = throwingMethod.getMethodName();
}
else if (ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption)) {
toAppend = String.valueOf(throwingMethod.getLineNumber());
}
else if (ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption)) {
toAppend = t.getMessage();
}
else if (ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption)) {
toAppend = t.getLocalizedMessage();
}
else if (ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption)) {
toAppend = throwingMethod.getFileName();
}
len = buffer.length();
if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
buffer.append(' ');
}
buffer.append(toAppend);
if (Strings.isNotBlank(suffix)) {
buffer.append(' ');
buffer.append(suffix);
}
}
}
private void formatOption(final Throwable throwable, final String suffix, final StringBuilder buffer) {
final int len = buffer.length();
if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
buffer.append(' ');
}
if (!options.allLines() || nonStandardLineSeparator || Strings.isNotBlank(suffix)) {
final StringWriter w = new StringWriter();
throwable.printStackTrace(new PrintWriter(w));
final String[] array = w.toString().split(Strings.LINE_SEPARATOR);
final int limit = options.minLines(array.length) - 1;
final boolean suffixNotBlank = Strings.isNotBlank(suffix);
for (int i = 0; i <= limit; ++i) {
buffer.append(array[i]);
if (suffixNotBlank) {
buffer.append(' ');
buffer.append(suffix);
}
if (i < limit) {
buffer.append(options.getSeparator());
}
}
} else {
throwable.printStackTrace(new PrintWriter(new StringBuilderWriter(buffer)));
}
}
/**
* This converter obviously handles throwables.
*
* @return true.
*/
@Override
public boolean handlesThrowable() {
return true;
}
protected String getSuffix(final LogEvent event) {
if (formatters.isEmpty()) {
return Strings.EMPTY;
}
//noinspection ForLoopReplaceableByForEach
final StringBuilder toAppendTo = new StringBuilder();
for (int i = 0, size = formatters.size(); i < size; i++) {
formatters.get(i).format(event, toAppendTo);
}
return toAppendTo.toString();
}
public ThrowableFormatOptions getOptions() {
return options;
}
}