groovy/src/main/org/codehaus/groovy/tools/ErrorReporter.java

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * Licensed 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.
 */


package org.codehaus.groovy.tools;

import java.io.PrintStream;
import java.io.PrintWriter;

import org.codehaus.groovy.GroovyExceptionInterface;
import org.codehaus.groovy.control.CompilationFailedException;
import groovy.lang.GroovyRuntimeException;


/**
 *  Provides services for reporting compilation errors to the
 *  user.  Primary entry point is <code>write()</code>.
 *
 *  @author <a href="mailto:cpoirier%20AT%20tapestry_os%20DOT%20org">Chris Poirier</a>
 *  @version $Revision$
 */

public class ErrorReporter
{
    private Throwable   base     = null;    // The exception on which to report
    private boolean     debug    = false;   // If true, stack traces are always output

    private Object      output   = null;    // The stream/writer to which to output


   /**
    *  Configures a new Reporter.  Default mode is not to report a stack trace unless
    *  the error was not of one of the supported types.
    *
    *  @param e  the exception on which to report
    */

    public ErrorReporter( Throwable e )
    {
        this.base     = e;
    }


   /**
    *  Configures a new Reporter.  
    *
    *  @param e      the exception on which to report
    *  @param debug  if set, stack traces will be output for all reports
    */

    public ErrorReporter( Throwable e, boolean debug )
    {
        this.base  = e;
        this.debug = debug;
    }


   /**
    *  Writes the error to the specified <code>PrintStream</code>.
    */

    public void write( PrintStream stream )
    {
        this.output = stream;
        dispatch( base, false );
        stream.flush();
    }


   /**
    *  Writes the error to the specified <code>PrintWriter</code>.
    */

    public void write( PrintWriter writer )
    {
        this.output = writer;
        dispatch( base, false );
        writer.flush();
    }


   /**
    *  Runs the report once all initialization is complete.
    */

    protected void dispatch( Throwable object, boolean child )
    {
        if( object instanceof CompilationFailedException )
        {
            report( (CompilationFailedException)object, child );
        }
        else if( object instanceof GroovyExceptionInterface )
        {
            report( (GroovyExceptionInterface)object, child );
        }
        else if( object instanceof GroovyRuntimeException )
        {
            report( (GroovyRuntimeException)object, child );
        }
        else if( object instanceof Exception )
        {
            report( (Exception)object, child );
        }
        else
        {
            report( object, child );
        }

    }



  //---------------------------------------------------------------------------
  // REPORTING ROUTINES


   /**
    *  For CompilationFailedException.
    */

    protected void report( CompilationFailedException e, boolean child )
    {
        println( e.toString() );
        stacktrace( e, false );
    }



   /**
    *  For GroovyException.
    */

    protected void report( GroovyExceptionInterface e, boolean child )
    {
        println( ((Exception)e).getMessage() );
        stacktrace( (Exception)e, false );
    }



   /**
    *  For Exception.
    */

    protected void report( Exception e, boolean child )
    {
        println( e.getMessage() );
        stacktrace( e, false );
    }



   /**
    *  For everything else.
    */

    protected void report( Throwable e, boolean child )
    {
        println( ">>> a serious error occurred: " + e.getMessage() );
        stacktrace( e, true );
    }



  //---------------------------------------------------------------------------
  // GENERAL SUPPORT ROUTINES


   /**
    *  Prints a line to the underlying <code>PrintStream</code>
    */

    protected void println( String line )
    {
        if( output instanceof PrintStream )
        {
            ((PrintStream)output).println( line );
        }
        else
        {
            ((PrintWriter)output).println( line );
        }
    }

    protected void println( StringBuffer line )
    {
        if( output instanceof PrintStream )
        {
            ((PrintStream)output).println( line );
        }
        else
        {
            ((PrintWriter)output).println( line );
        }
    }


   /**
    *  Displays an exception's stack trace, if <code>debug</code> or 
    *  <code>always</code>.
    */

    protected void stacktrace( Throwable e, boolean always )
    {
        if( debug || always )
        {
            println( ">>> stacktrace:" );
            if( output instanceof PrintStream )
            {
                e.printStackTrace( (PrintStream)output );
            }
            else
            {
                e.printStackTrace( (PrintWriter)output );
            }
        }
    }



}