001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.pattern;
018
019import java.io.PrintWriter;
020import java.io.StringWriter;
021import java.util.ArrayList;
022import java.util.Collections;
023import java.util.List;
024
025import org.apache.logging.log4j.core.LogEvent;
026import org.apache.logging.log4j.core.config.Configuration;
027import org.apache.logging.log4j.core.config.plugins.Plugin;
028import org.apache.logging.log4j.core.impl.ThrowableFormatOptions;
029import org.apache.logging.log4j.core.layout.PatternLayout;
030import org.apache.logging.log4j.util.Strings;
031
032
033/**
034 * Outputs the Throwable portion of the LoggingEvent as a full stack trace
035 * unless this converter's option is 'short', where it just outputs the first line of the trace, or if
036 * the number of lines to print is explicitly specified.
037 */
038@Plugin(name = "ThrowablePatternConverter", category = PatternConverter.CATEGORY)
039@ConverterKeys({ "ex", "throwable", "exception" })
040public class ThrowablePatternConverter extends LogEventPatternConverter {
041
042    protected final List<PatternFormatter> formatters;
043    private String rawOption;
044
045    /**
046     * The number of lines to write.
047     */
048    protected final ThrowableFormatOptions options;
049
050    /**
051     * Constructor.
052     * @param name Name of converter.
053     * @param style CSS style for output.
054     * @param options options, may be null.
055     * @param config
056     */
057    protected ThrowablePatternConverter(final String name, final String style, final String[] options, final Configuration config) {
058        super(name, style);
059        this.options = ThrowableFormatOptions.newInstance(options);
060        if (options != null && options.length > 0) {
061            rawOption = options[0];
062        }
063        if (this.options.getSuffix() != null) {
064            final PatternParser parser = PatternLayout.createPatternParser(config);
065            final List<PatternFormatter> parsedFormatters = parser.parse(this.options.getSuffix());
066            // filter out nested formatters that will handle throwable
067            boolean hasThrowableFormatter = false;
068            for (final PatternFormatter formatter : parsedFormatters) {
069                if (formatter.handlesThrowable()) {
070                    hasThrowableFormatter = true;
071                }
072            }
073            if (!hasThrowableFormatter) {
074                this.formatters = parsedFormatters;
075            } else {
076                final List<PatternFormatter> formatters = new ArrayList<>();
077                for (final PatternFormatter formatter : parsedFormatters) {
078                    if (!formatter.handlesThrowable()) {
079                        formatters.add(formatter);
080                    }
081                }
082                this.formatters = formatters;
083            }
084        } else {
085            this.formatters = Collections.emptyList();
086        }
087
088    }
089
090    /**
091     * Gets an instance of the class.
092     *
093     *
094     * @param config
095     * @param options pattern options, may be null.  If first element is "short",
096     *                only the first line of the throwable will be formatted.
097     * @return instance of class.
098     */
099    public static ThrowablePatternConverter newInstance(final Configuration config, final String[] options) {
100        return new ThrowablePatternConverter("Throwable", "throwable", options, config);
101    }
102
103    /**
104     * {@inheritDoc}
105     */
106    @Override
107    public void format(final LogEvent event, final StringBuilder buffer) {
108        final Throwable t = event.getThrown();
109
110        if (isSubShortOption()) {
111            formatSubShortOption(t, getSuffix(event), buffer);
112        }
113        else if (t != null && options.anyLines()) {
114            formatOption(t, getSuffix(event), buffer);
115        }
116    }
117
118    private boolean isSubShortOption() {
119        return ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
120                ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
121                ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
122                ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
123                ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
124                ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
125    }
126
127    private void formatSubShortOption(final Throwable t, final String suffix, final StringBuilder buffer) {
128        StackTraceElement[] trace;
129        StackTraceElement throwingMethod = null;
130        int len;
131
132        if (t != null) {
133            trace = t.getStackTrace();
134            if (trace !=null && trace.length > 0) {
135                throwingMethod = trace[0];
136            }
137        }
138
139        if (t != null && throwingMethod != null) {
140            String toAppend = Strings.EMPTY;
141
142            if (ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption)) {
143                toAppend = throwingMethod.getClassName();
144            }
145            else if (ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption)) {
146                toAppend = throwingMethod.getMethodName();
147            }
148            else if (ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption)) {
149                toAppend = String.valueOf(throwingMethod.getLineNumber());
150            }
151            else if (ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption)) {
152                toAppend = t.getMessage();
153            }
154            else if (ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption)) {
155                toAppend = t.getLocalizedMessage();
156            }
157            else if (ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption)) {
158                toAppend = throwingMethod.getFileName();
159            }
160
161            len = buffer.length();
162            if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
163                buffer.append(' ');
164            }
165            buffer.append(toAppend);
166
167            if (Strings.isNotBlank(suffix)) {
168                buffer.append(' ');
169                buffer.append(suffix);
170            }
171        }
172    }
173
174    private void formatOption(final Throwable throwable, final String suffix, final StringBuilder buffer) {
175        final StringWriter w = new StringWriter();
176
177        throwable.printStackTrace(new PrintWriter(w));
178        final int len = buffer.length();
179        if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
180            buffer.append(' ');
181        }
182        if (!options.allLines() || !Strings.LINE_SEPARATOR.equals(options.getSeparator()) || Strings.isNotBlank(suffix)) {
183            final StringBuilder sb = new StringBuilder();
184            final String[] array = w.toString().split(Strings.LINE_SEPARATOR);
185            final int limit = options.minLines(array.length) - 1;
186            final boolean suffixNotBlank = Strings.isNotBlank(suffix);
187            for (int i = 0; i <= limit; ++i) {
188                sb.append(array[i]);
189                if (suffixNotBlank) {
190                    sb.append(' ');
191                    sb.append(suffix);
192                }
193                if (i < limit) {
194                    sb.append(options.getSeparator());
195                }
196            }
197            buffer.append(sb.toString());
198
199        } else {
200            buffer.append(w.toString());
201        }
202    }
203
204    /**
205     * This converter obviously handles throwables.
206     *
207     * @return true.
208     */
209    @Override
210    public boolean handlesThrowable() {
211        return true;
212    }
213
214    protected String getSuffix(final LogEvent event) {
215        //noinspection ForLoopReplaceableByForEach
216        final StringBuilder toAppendTo = new StringBuilder();
217        for (int i = 0, size = formatters.size(); i <  size; i++) {
218            formatters.get(i).format(event, toAppendTo);
219        }
220        return toAppendTo.toString();
221    }
222}