    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     */
    017    package org.apache.logging.log4j.core.pattern;
    018
    019    import java.io.PrintWriter;
    020    import java.io.StringWriter;
    021
    022    import org.apache.logging.log4j.core.LogEvent;
    023    import org.apache.logging.log4j.core.config.plugins.Plugin;
    024    import org.apache.logging.log4j.core.impl.ThrowableFormatOptions;
    025    import org.apache.logging.log4j.core.util.Constants;
    026    import org.apache.logging.log4j.util.Strings;
    027
    028
    029    /**
    030     * Outputs the Throwable portion of the LoggingEvent as a full stack trace
    031     * unless this converter's option is 'short', where it just outputs the first line of the trace, or if
    032     * the number of lines to print is explicitly specified.
    033     */
    034    @Plugin(name = "ThrowablePatternConverter", category = PatternConverter.CATEGORY)
    035    @ConverterKeys({ "ex", "throwable", "exception" })
    036    public class ThrowablePatternConverter extends LogEventPatternConverter {
    037
    038        private String rawOption;
    039
    040        /**
    041         * The number of lines to write.
    042         */
    043        protected final ThrowableFormatOptions options;
    044
    045        /**
    046         * Constructor.
    047         * @param name Name of converter.
    048         * @param style CSS style for output.
    049         * @param options options, may be null.
    050         */
    051        protected ThrowablePatternConverter(final String name, final String style, final String[] options) {
    052            super(name, style);
    053            this.options = ThrowableFormatOptions.newInstance(options);
    054            if (options != null && options.length > 0) {
    055                rawOption = options[0];
    056            }
    057        }
    058
    059        /**
    060         * Gets an instance of the class.
    061         *
    062         * @param options pattern options, may be null.  If first element is "short",
    063         *                only the first line of the throwable will be formatted.
    064         * @return instance of class.
    065         */
    066        public static ThrowablePatternConverter newInstance(final String[] options) {
    067            return new ThrowablePatternConverter("Throwable", "throwable", options);
    068        }
    069
    070        /**
    071         * {@inheritDoc}
    072         */
    073        @Override
    074        public void format(final LogEvent event, final StringBuilder buffer) {
    075            final Throwable t = event.getThrown();
    076
    077            if (isSubShortOption()) {
    078                formatSubShortOption(t, buffer);
    079            }
    080            else if (t != null && options.anyLines()) {
    081                formatOption(t, buffer);
    082            }
    083        }
    084
    085        private boolean isSubShortOption() {
    086            return ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
    087                    ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
    088                    ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
    089                    ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
    090                    ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
    091                    ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
    092        }
    093
    094        private void formatSubShortOption(final Throwable t, final StringBuilder buffer) {
    095            StackTraceElement[] trace;
    096            StackTraceElement throwingMethod = null;
    097            int len;
    098
    099            if (t != null) {
    100                trace = t.getStackTrace();
    101                if (trace !=null && trace.length > 0) {
    102                    throwingMethod = trace[0];
    103                }
    104            }
    105
    106            if (t != null && throwingMethod != null) {
    107                String toAppend = Strings.EMPTY;
    108
    109                if (ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption)) {
    110                    toAppend = throwingMethod.getClassName();
    111                }
    112                else if (ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption)) {
    113                    toAppend = throwingMethod.getMethodName();
    114                }
    115                else if (ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption)) {
    116                    toAppend = String.valueOf(throwingMethod.getLineNumber());
    117                }
    118                else if (ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption)) {
    119                    toAppend = t.getMessage();
    120                }
    121                else if (ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption)) {
    122                    toAppend = t.getLocalizedMessage();
    123                }
    124                else if (ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption)) {
    125                    toAppend = throwingMethod.getFileName();
    126                }
    127
    128                len = buffer.length();
    129                if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
    130                    buffer.append(' ');
    131                }
    132                buffer.append(toAppend);
    133            }
    134        }
    135
    136        private void formatOption(final Throwable throwable, final StringBuilder buffer) {
    137            final StringWriter w = new StringWriter();
    138
    139            throwable.printStackTrace(new PrintWriter(w));
    140            final int len = buffer.length();
    141            if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
    142                buffer.append(' ');
    143            }
    144            if (!options.allLines() || !Constants.LINE_SEPARATOR.equals(options.getSeparator())) {
    145                final StringBuilder sb = new StringBuilder();
    146                final String[] array = w.toString().split(Constants.LINE_SEPARATOR);
    147                final int limit = options.minLines(array.length) - 1;
    148                for (int i = 0; i <= limit; ++i) {
    149                    sb.append(array[i]);
    150                    if (i < limit) {
    151                        sb.append(options.getSeparator());
    152                    }
    153                }
    154                buffer.append(sb.toString());
    155
    156            } else {
    157                buffer.append(w.toString());
    158            }
    159        }
    160
    161        /**
    162         * This converter obviously handles throwables.
    163         *
    164         * @return true.
    165         */
    166        @Override
    167        public boolean handlesThrowable() {
    168            return true;
    169        }
    170    }