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    /**
043     * Lists {@link PatternFormatter}s for the suffix attribute.
044     */
045    protected final List<PatternFormatter> formatters;
046    private String rawOption;
047
048    /**
049     * Options.
050     */
051    protected final ThrowableFormatOptions options;
052
053    /**
054     * Constructor.
055     * @param name Name of converter.
056     * @param style CSS style for output.
057     * @param options options, may be null.
058     * @param config
059     */
060    protected ThrowablePatternConverter(final String name, final String style, final String[] options, final Configuration config) {
061        super(name, style);
062        this.options = ThrowableFormatOptions.newInstance(options);
063        if (options != null && options.length > 0) {
064            rawOption = options[0];
065        }
066        if (this.options.getSuffix() != null) {
067            final PatternParser parser = PatternLayout.createPatternParser(config);
068            final List<PatternFormatter> parsedSuffixFormatters = parser.parse(this.options.getSuffix());
069            // filter out nested formatters that will handle throwable
070            boolean hasThrowableSuffixFormatter = false;
071            for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
072                if (suffixFormatter.handlesThrowable()) {
073                    hasThrowableSuffixFormatter = true;
074                }
075            }
076            if (!hasThrowableSuffixFormatter) {
077                this.formatters = parsedSuffixFormatters;
078            } else {
079                final List<PatternFormatter> suffixFormatters = new ArrayList<>();
080                for (final PatternFormatter suffixFormatter : parsedSuffixFormatters) {
081                    if (!suffixFormatter.handlesThrowable()) {
082                        suffixFormatters.add(suffixFormatter);
083                    }
084                }
085                this.formatters = suffixFormatters;
086            }
087        } else {
088            this.formatters = Collections.emptyList();
089        }
090
091    }
092
093    /**
094     * Gets an instance of the class.
095     *
096     * @param config
097     * @param options pattern options, may be null.  If first element is "short",
098     *                only the first line of the throwable will be formatted.
099     * @return instance of class.
100     */
101    public static ThrowablePatternConverter newInstance(final Configuration config, final String[] options) {
102        return new ThrowablePatternConverter("Throwable", "throwable", options, config);
103    }
104
105    /**
106     * {@inheritDoc}
107     */
108    @Override
109    public void format(final LogEvent event, final StringBuilder buffer) {
110        final Throwable t = event.getThrown();
111
112        if (isSubShortOption()) {
113            formatSubShortOption(t, getSuffix(event), buffer);
114        }
115        else if (t != null && options.anyLines()) {
116            formatOption(t, getSuffix(event), buffer);
117        }
118    }
119
120    private boolean isSubShortOption() {
121        return ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
122                ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
123                ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
124                ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
125                ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
126                ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
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 StringWriter w = new StringWriter();
178
179        throwable.printStackTrace(new PrintWriter(w));
180        final int len = buffer.length();
181        if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
182            buffer.append(' ');
183        }
184        if (!options.allLines() || !Strings.LINE_SEPARATOR.equals(options.getSeparator()) || Strings.isNotBlank(suffix)) {
185            final StringBuilder sb = new StringBuilder();
186            final String[] array = w.toString().split(Strings.LINE_SEPARATOR);
187            final int limit = options.minLines(array.length) - 1;
188            final boolean suffixNotBlank = Strings.isNotBlank(suffix);
189            for (int i = 0; i <= limit; ++i) {
190                sb.append(array[i]);
191                if (suffixNotBlank) {
192                    sb.append(' ');
193                    sb.append(suffix);
194                }
195                if (i < limit) {
196                    sb.append(options.getSeparator());
197                }
198            }
199            buffer.append(sb.toString());
200
201        } else {
202            buffer.append(w.toString());
203        }
204    }
205
206    /**
207     * This converter obviously handles throwables.
208     *
209     * @return true.
210     */
211    @Override
212    public boolean handlesThrowable() {
213        return true;
214    }
215
216    protected String getSuffix(final LogEvent event) {
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}