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.core.util.StringBuilderWriter;
031import org.apache.logging.log4j.util.Strings;
032
033
034/**
035 * Outputs the Throwable portion of the LoggingEvent as a full stack trace
036 * unless this converter's option is 'short', where it just outputs the first line of the trace, or if
037 * the number of lines to print is explicitly specified.
038 */
039@Plugin(name = "ThrowablePatternConverter", category = PatternConverter.CATEGORY)
040@ConverterKeys({ "ex", "throwable", "exception" })
041public class ThrowablePatternConverter extends LogEventPatternConverter {
042
043    /**
044     * Lists {@link PatternFormatter}s for the suffix attribute.
045     */
046    protected final List<PatternFormatter> formatters;
047    private String rawOption;
048    private final boolean subShortOption;
049    private final boolean nonStandardLineSeparator;
050
051    /**
052     * Options.
053     */
054    protected final ThrowableFormatOptions options;
055
056    /**
057     * Constructor.
058     * @param name Name of converter.
059     * @param style CSS style for output.
060     * @param options options, may be null.
061     * @param config
062     */
063    protected ThrowablePatternConverter(final String name, final String style, final String[] options, final Configuration config) {
064        super(name, style);
065        this.options = ThrowableFormatOptions.newInstance(options);
066        if (options != null && options.length > 0) {
067            rawOption = options[0];
068        }
069        if (this.options.getSuffix() != null) {
070            final PatternParser parser = PatternLayout.createPatternParser(config);
071            final List<PatternFormatter> parsedSuffixFormatters = parser.parse(this.options.getSuffix());
072            // filter out nested formatters that will handle throwable
073            boolean hasThrowableSuffixFormatter = false;
074            for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
075                if (suffixFormatter.handlesThrowable()) {
076                    hasThrowableSuffixFormatter = true;
077                }
078            }
079            if (!hasThrowableSuffixFormatter) {
080                this.formatters = parsedSuffixFormatters;
081            } else {
082                final List<PatternFormatter> suffixFormatters = new ArrayList<>();
083                for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
084                    if (!suffixFormatter.handlesThrowable()) {
085                        suffixFormatters.add(suffixFormatter);
086                    }
087                }
088                this.formatters = suffixFormatters;
089            }
090        } else {
091            this.formatters = Collections.emptyList();
092        }
093        subShortOption = ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
094                ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
095                ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
096                ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
097                ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
098                ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
099        nonStandardLineSeparator = !Strings.LINE_SEPARATOR.equals(this.options.getSeparator());
100    }
101
102    /**
103     * Gets an instance of the class.
104     *
105     * @param config
106     * @param options pattern options, may be null.  If first element is "short",
107     *                only the first line of the throwable will be formatted.
108     * @return instance of class.
109     */
110    public static ThrowablePatternConverter newInstance(final Configuration config, final String[] options) {
111        return new ThrowablePatternConverter("Throwable", "throwable", options, config);
112    }
113
114    /**
115     * {@inheritDoc}
116     */
117    @Override
118    public void format(final LogEvent event, final StringBuilder buffer) {
119        final Throwable t = event.getThrown();
120
121        if (subShortOption) {
122            formatSubShortOption(t, getSuffix(event), buffer);
123        }
124        else if (t != null && options.anyLines()) {
125            formatOption(t, getSuffix(event), buffer);
126        }
127    }
128
129    private void formatSubShortOption(final Throwable t, final String suffix, final StringBuilder buffer) {
130        StackTraceElement[] trace;
131        StackTraceElement throwingMethod = null;
132        int len;
133
134        if (t != null) {
135            trace = t.getStackTrace();
136            if (trace !=null && trace.length > 0) {
137                throwingMethod = trace[0];
138            }
139        }
140
141        if (t != null && throwingMethod != null) {
142            String toAppend = Strings.EMPTY;
143
144            if (ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption)) {
145                toAppend = throwingMethod.getClassName();
146            }
147            else if (ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption)) {
148                toAppend = throwingMethod.getMethodName();
149            }
150            else if (ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption)) {
151                toAppend = String.valueOf(throwingMethod.getLineNumber());
152            }
153            else if (ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption)) {
154                toAppend = t.getMessage();
155            }
156            else if (ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption)) {
157                toAppend = t.getLocalizedMessage();
158            }
159            else if (ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption)) {
160                toAppend = throwingMethod.getFileName();
161            }
162
163            len = buffer.length();
164            if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
165                buffer.append(' ');
166            }
167            buffer.append(toAppend);
168
169            if (Strings.isNotBlank(suffix)) {
170                buffer.append(' ');
171                buffer.append(suffix);
172            }
173        }
174    }
175
176    private void formatOption(final Throwable throwable, final String suffix, final StringBuilder buffer) {
177        final int len = buffer.length();
178        if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
179            buffer.append(' ');
180        }
181        if (!options.allLines() || nonStandardLineSeparator || Strings.isNotBlank(suffix)) {
182            final StringWriter w = new StringWriter();
183            throwable.printStackTrace(new PrintWriter(w));
184
185            final String[] array = w.toString().split(Strings.LINE_SEPARATOR);
186            final int limit = options.minLines(array.length) - 1;
187            final boolean suffixNotBlank = Strings.isNotBlank(suffix);
188            for (int i = 0; i <= limit; ++i) {
189                buffer.append(array[i]);
190                if (suffixNotBlank) {
191                    buffer.append(' ');
192                    buffer.append(suffix);
193                }
194                if (i < limit) {
195                    buffer.append(options.getSeparator());
196                }
197            }
198        } else {
199            throwable.printStackTrace(new PrintWriter(new StringBuilderWriter(buffer)));
200        }
201    }
202
203    /**
204     * This converter obviously handles throwables.
205     *
206     * @return true.
207     */
208    @Override
209    public boolean handlesThrowable() {
210        return true;
211    }
212
213    protected String getSuffix(final LogEvent event) {
214        if (formatters.isEmpty()) {
215            return Strings.EMPTY;
216        }
217        //noinspection ForLoopReplaceableByForEach
218        final StringBuilder toAppendTo = new StringBuilder();
219        for (int i = 0, size = formatters.size(); i <  size; i++) {
220            formatters.get(i).format(event, toAppendTo);
221        }
222        return toAppendTo.toString();
223    }
224
225    public ThrowableFormatOptions getOptions() {
226        return options;
227    }
228}