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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.core.pattern;
    18
    19  import org.apache.logging.log4j.core.LogEvent;
    20  import org.apache.logging.log4j.core.config.plugins.Plugin;
    21  import org.apache.logging.log4j.core.impl.Log4jLogEvent;
    22  import org.apache.logging.log4j.core.impl.ThrowableProxy;
    23  import org.apache.logging.log4j.core.util.Constants;
    24
    25  /**
    26   * Outputs the Throwable portion of the LoggingEvent as a full stack trace
    27   * unless this converter's option is 'short', where it just outputs the first line of the trace, or if
    28   * the number of lines to print is explicitly specified.
    29   * <p>
    30   * The extended stack trace will also include the location of where the class was loaded from and the
    31   * version of the jar if available.
    32   */
    33  @Plugin(name = "RootThrowablePatternConverter", category = PatternConverter.CATEGORY)
    34  @ConverterKeys({ "rEx", "rThrowable", "rException" })
    35  public final class RootThrowablePatternConverter extends ThrowablePatternConverter {
    36
    37      /**
    38       * Private constructor.
    39       *
    40       * @param options options, may be null.
    41       */
    42      private RootThrowablePatternConverter(final String[] options) {
    43          super("RootThrowable", "throwable", options);
    44      }
    45
    46      /**
    47       * Gets an instance of the class.
    48       *
    49       * @param options pattern options, may be null.  If first element is "short",
    50       *                only the first line of the throwable will be formatted.
    51       * @return instance of class.
    52       */
    53      public static RootThrowablePatternConverter newInstance(final String[] options) {
    54          return new RootThrowablePatternConverter(options);
    55      }
    56
    57      /**
    58       * {@inheritDoc}
    59       */
    60      @Override
    61      public void format(final LogEvent event, final StringBuilder toAppendTo) {
    62          ThrowableProxy proxy = null;
    63          if (event instanceof Log4jLogEvent) {
    64              proxy = ((Log4jLogEvent) event).getThrownProxy();
    65          }
    66          final Throwable throwable = event.getThrown();
    67          if (throwable != null && options.anyLines()) {
    68              if (proxy == null) {
    69                  super.format(event, toAppendTo);
    70                  return;
    71              }
    72              final String trace = proxy.getCauseStackTraceAsString(options.getPackages());
    73              final int len = toAppendTo.length();
    74              if (len > 0 && !Character.isWhitespace(toAppendTo.charAt(len - 1))) {
    75                  toAppendTo.append(' ');
    76              }
    77              if (!options.allLines() || !Constants.LINE_SEPARATOR.equals(options.getSeparator())) {
    78                  final StringBuilder sb = new StringBuilder();
    79                  final String[] array = trace.split(Constants.LINE_SEPARATOR);
    80                  final int limit = options.minLines(array.length) - 1;
    81                  for (int i = 0; i <= limit; ++i) {
    82                      sb.append(array[i]);
    83                      if (i < limit) {
    84                          sb.append(options.getSeparator());
    85                      }
    86                  }
    87                  toAppendTo.append(sb.toString());
    88
    89              } else {
    90                  toAppendTo.append(trace);
    91              }
    92          }
    93      }
    94  }