/*
    * Copyright 2010-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.xml.handler;
  
  import java.io.PrintStream;
  import java.io.PrintWriter;
  
  import javax.xml.transform.ErrorListener;
  import javax.xml.transform.SourceLocator;
  import javax.xml.transform.TransformerException;
  
  import org.xml.sax.ErrorHandler;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  
  /**
   * Implements SAX error handler for default reporting.
   */
  public class DefaultErrorHandler implements ErrorHandler, ErrorListener
  { // NOPMD
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The writer to write fatals, errors and warnings to.
     */
    private final PrintWriter messageWriter;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Convenience constructor passing in a stream, not rethrowing exceptions.
     *
     * @param messageStream the stream to write messages to.
     */
    public DefaultErrorHandler(final PrintStream messageStream)
    {
      this(new PrintWriter(messageStream, true));
    }
  
    /**
     * Convenience constructor for writing to <code>System.err</code>.
     */
    public DefaultErrorHandler()
    {
      this(new PrintWriter(System.err, true));
    }
  
    /**
     * Constructor constructor.
     *
     * @param messageWriter the writer to write fatals, errors and warnings to.
     */
    public DefaultErrorHandler(final PrintWriter messageWriter)
    {
      this.messageWriter = messageWriter;
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    // --- business -------------------------------------------------------------
  
    @Override
    public void warning(final TransformerException exception)
      throws TransformerException
    {
      print(exception, "Transformer Warning");
    }
  
    @Override
    public void error(final TransformerException exception)
      throws TransformerException
    {
      print(exception, "Transformer Error");
    }
 
   @Override
   public void fatalError(final TransformerException exception)
     throws TransformerException
   {
     print(exception, "Fatal Transformer Error");
   }
 
   @Override
   public void warning(final SAXParseException exception) throws SAXException
   {
     print(exception, "Parse Warning");
   }
 
   @Override
   public void error(final SAXParseException exception) throws SAXException
   {
     print(exception, "Parse Error");
   }
 
   @Override
   public void fatalError(final SAXParseException exception) throws SAXException
   {
     print(exception, "Fatal Parse Error");
   }
 
   // ... helper
 
   private void print(final Throwable exception, final String type)
   {
     printLocation(exception);
     messageWriter.println(type + ": " + exception.getMessage());
   }
 
   private void printLocation(final Throwable exception)
   {
     final SourceLocator locator = calcLocator(exception);
     printMessage(locator);
   }
 
   private void printMessage(final SourceLocator locator)
   {
     if (null != locator)
     {
       final String publicId = locator.getPublicId();
       final String systemId = locator.getSystemId();
 
       final String id =
           (null != publicId) ? publicId : (null != systemId) ? systemId
               : "unknown XML ID";
 
       messageWriter.print(id + ": line " + locator.getLineNumber()
                           + " / column " + locator.getColumnNumber());
     }
     else
     {
       messageWriter.print("(unknown location)");
     }
   }
 
   @SuppressWarnings("restriction")
   private SourceLocator calcLocator(final Throwable exception)
   {
     SourceLocator locator = null;
     Throwable cause = exception;
 
     do
     {
       if (cause instanceof SAXParseException)
       {
         locator =
             new com.sun.org.apache.xml.internal.utils.SAXSourceLocator(
                 (SAXParseException) cause);
       }
       else if (cause instanceof TransformerException)
       {
         locator = handleTransformerException(locator, cause);
       }
 
       if (cause instanceof TransformerException)
       {
         cause = ((TransformerException) cause).getCause();
       }
       else if (cause instanceof com.sun.org.apache.xml.internal.utils.WrappedRuntimeException)
       {
         cause =
             ((com.sun.org.apache.xml.internal.utils.WrappedRuntimeException) cause)
                 .getException();
       }
       else if (cause instanceof SAXException)
       {
         cause = ((SAXException) cause).getException();
       }
       else
       {
         cause = null;
       }
     }
     while (null != cause);
 
     return locator;
   }
 
   private SourceLocator handleTransformerException(final SourceLocator locator,
       final Throwable cause)
   {
     final SourceLocator causeLocator =
         ((TransformerException) cause).getLocator();
     if (null != causeLocator)
     {
       return causeLocator;
     }
     return locator;
   }
 
   // --- object basics --------------------------------------------------------
 
 }