package org.apache.maven.shared.invoker;
   
   /*
    * 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 java.io.PrintStream;
  import java.io.PrintWriter;
  import java.io.StringWriter;
  
  /**
   * Offers a logger that writes to a print stream like {@link java.lang.System#out}.
   *
   * @since 2.0.9
   */
  public class PrintStreamLogger
      implements InvokerLogger
  {
  
      /**
       * The print stream to write to, never <code>null</code>.
       */
      private PrintStream out;
  
      /**
       * The threshold used to filter messages.
       */
      private int threshold;
  
      /**
       * Creates a new logger that writes to {@link java.lang.System#out} and has a threshold of {@link #INFO}.
       */
      public PrintStreamLogger()
      {
          this( System.out, INFO );
      }
  
      /**
       * Creates a new logger that writes to the specified print stream.
       *
       * @param out The print stream to write to, must not be <code>null</code>.
       * @param threshold The threshold for the logger.
       */
      public PrintStreamLogger( PrintStream out, int threshold )
      {
          if ( out == null )
          {
              throw new NullPointerException( "missing output stream" );
          }
          this.out = out;
          setThreshold( threshold );
      }
  
      /**
       * Writes the specified message and exception to the print stream.
       * 
       * @param level The priority level of the message.
       * @param message The message to log, may be <code>null</code>.
       * @param error The exception to log, may be <code>null</code>.
       */
      private void log( int level, String message, Throwable error )
      {
          if ( level > threshold )
          {
              // don't log when it doesn't match your threshold.
              return;
          }
  
          if ( message == null && error == null )
          {
              // don't log when there's nothing to log.
              return;
          }
  
          StringBuilder buffer = new StringBuilder();
  
          switch ( level )
          {
              case ( DEBUG ):
                  buffer.append( "[DEBUG]" );
                  break;
  
              case ( INFO ):
                  buffer.append( "[INFO]" );
                 break;
 
             case ( WARN ):
                 buffer.append( "[WARN]" );
                 break;
 
             case ( ERROR ):
                 buffer.append( "[ERROR]" );
                 break;
 
             case ( FATAL ):
                 buffer.append( "[FATAL]" );
                 break;
 
             default:
         }
 
         buffer.append( ' ' );
 
         if ( message != null )
         {
             buffer.append( message );
         }
 
         if ( error != null )
         {
             StringWriter writer = new StringWriter();
             PrintWriter pWriter = new PrintWriter( writer );
 
             error.printStackTrace( pWriter );
 
             if ( message != null )
             {
                 buffer.append( '\n' );
             }
 
             buffer.append( "Error:\n" );
             buffer.append( writer.toString() );
         }
 
         out.println( buffer.toString() );
     }
 
     /** {@inheritDoc} */
     public void debug( String message )
     {
         log( DEBUG, message, null );
     }
 
     /** {@inheritDoc} */
     public void debug( String message, Throwable throwable )
     {
         log( DEBUG, message, throwable );
     }
 
     /** {@inheritDoc} */
     public void info( String message )
     {
         log( INFO, message, null );
     }
 
     /** {@inheritDoc} */
     public void info( String message, Throwable throwable )
     {
         log( INFO, message, throwable );
     }
 
     /** {@inheritDoc} */
     public void warn( String message )
     {
         log( WARN, message, null );
     }
 
     /** {@inheritDoc} */
     public void warn( String message, Throwable throwable )
     {
         log( WARN, message, throwable );
     }
 
     /** {@inheritDoc} */
     public void error( String message )
     {
         log( ERROR, message, null );
     }
 
     /** {@inheritDoc} */
     public void error( String message, Throwable throwable )
     {
         log( ERROR, message, throwable );
     }
 
     /** {@inheritDoc} */
     public void fatalError( String message )
     {
         log( FATAL, message, null );
     }
 
     /** {@inheritDoc} */
     public void fatalError( String message, Throwable throwable )
     {
         log( FATAL, message, throwable );
     }
 
     /**
      * <p>isDebugEnabled.</p>
      *
      * @return a boolean.
      */
     public boolean isDebugEnabled()
     {
         return threshold >= DEBUG;
     }
 
     /**
      * <p>isErrorEnabled.</p>
      *
      * @return a boolean.
      */
     public boolean isErrorEnabled()
     {
         return threshold >= ERROR;
     }
 
     /**
      * <p>isFatalErrorEnabled.</p>
      *
      * @return a boolean.
      */
     public boolean isFatalErrorEnabled()
     {
         return threshold >= FATAL;
     }
 
     /**
      * <p>isInfoEnabled.</p>
      *
      * @return a boolean.
      */
     public boolean isInfoEnabled()
     {
         return threshold >= INFO;
     }
 
     /**
      * <p>isWarnEnabled.</p>
      *
      * @return a boolean.
      */
     public boolean isWarnEnabled()
     {
         return threshold >= WARN;
     }
 
     /**
      * <p>Getter for the field <code>threshold</code>.</p>
      *
      * @return a int.
      */
     public int getThreshold()
     {
         return threshold;
     }
 
     /** {@inheritDoc} */
     public void setThreshold( int threshold )
     {
         this.threshold = threshold;
     }
 
 }