package org.codehaus.mojo.jaxb2.shared.environment.logging;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import org.apache.maven.plugin.logging.Log;
  import org.codehaus.mojo.jaxb2.shared.Validate;
  
  import java.io.UnsupportedEncodingException;
  import java.util.Arrays;
  import java.util.List;
  import java.util.logging.Filter;
  import java.util.logging.Handler;
  import java.util.logging.Level;
  import java.util.logging.LogRecord;
  import java.util.logging.SimpleFormatter;
  
  /**
   * Handler implementation which delegates its actual logging to an internal Maven log.
   *
   * @author <a href="mailto:lj@jguru.se">Lennart J&ouml;relid</a>, jGuru Europe AB
   * @since 2.0
   */
  public class MavenLogHandler extends Handler {
  
      // Internal state
      private Log log;
      private String prefix;
  
      /**
       * Creates a new MavenLogHandler which adapts a Handler to emit log messages onto a Maven Log.
       *
       * @param log                       The Maven Log to emit log messages to.
       * @param prefix                    An optional prefix used to prefix any log message.
       * @param encoding                  The encoding which should be used.
       * @param acceptedLogRecordPrefixes A non-null list of prefixes holding LogRecord logger names for
       *                                  permitted/accepted LogRecords.
       */
      public MavenLogHandler(final Log log,
                             final String prefix,
                             final String encoding,
                             final String[] acceptedLogRecordPrefixes) {
  
          // Check sanity
          Validate.notNull(log, "log");
          Validate.notNull(prefix, "prefix");
          Validate.notEmpty(encoding, "encoding");
  
          // Assign internal state
          this.log = log;
          this.prefix = prefix.isEmpty() ? "" : "[" + prefix + "]: ";
  
          setFormatter(new SimpleFormatter());
          setLevel(getJavaUtilLoggingLevelFor(log));
          try {
              setEncoding(encoding);
          } catch (UnsupportedEncodingException e) {
              log.error("Could not use encoding '" + encoding + "'", e);
          }
  
          if (acceptedLogRecordPrefixes != null && acceptedLogRecordPrefixes.length > 0) {
              setFilter(getLoggingFilter(acceptedLogRecordPrefixes));
          }
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void publish(final LogRecord record) {
  
          if (this.isLoggable(record)) {
  
              final Level level = record.getLevel();
              final String message = prefix + getFormatter().format(record);
  
              if (Level.SEVERE.equals(level)) {
                  log.error(message);
              } else if (Level.WARNING.equals(level)) {
                  log.warn(message);
              } else if (Level.INFO.equals(level)) {
                  log.info(message);
              } else {
                 log.debug(message);
             }
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void flush() {
         // Do nothing.
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void close() throws SecurityException {
         // Do nothing.
     }
 
     /**
      * Retrieves the JUL Level matching the supplied Maven Log.
      *
      * @param mavenLog A non-null Maven Log.
      * @return The Corresponding JUL Level.
      */
     public static Level getJavaUtilLoggingLevelFor(final Log mavenLog) {
 
         // Check sanity
         Validate.notNull(mavenLog, "mavenLog");
 
         Level toReturn = Level.SEVERE;
 
         if (mavenLog.isDebugEnabled()) {
             toReturn = Level.FINER;
         } else if (mavenLog.isInfoEnabled()) {
             toReturn = Level.INFO;
         } else if (mavenLog.isWarnEnabled()) {
             toReturn = Level.WARNING;
         }
 
         // All Done.
         return toReturn;
     }
 
     /**
      * Retrieves a java.util.Logging filter used to ensure that only LogRecords whose
      * logger names start with any of the required prefixes are logged.
      *
      * @param requiredPrefixes A non-null list of prefixes to be matched with the LogRecord logger names.
      * @return A java.util.logging Filter that only permits logging LogRecords whose
      * logger names start with any of the required prefixes.
      */
     public static Filter getLoggingFilter(final String... requiredPrefixes) {
 
         // Check sanity
         Validate.notNull(requiredPrefixes, "requiredPrefixes");
 
         // All done.
         return new Filter() {
 
             // Internal state
             private List<String> requiredPrefs = Arrays.asList(requiredPrefixes);
 
             @Override
             public boolean isLoggable(final LogRecord record) {
 
                 final String loggerName = record.getLoggerName();
                 for (String current : requiredPrefs) {
                     if (loggerName.startsWith(current)) {
                         return true;
                     }
                 }
 
                 // No matches found.
                 return false;
             }
         };
     }
 }