/**
    *
    * Copyright 2006 The Apache Software Foundation
    *
    *  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.
   */
  
  /*
   * This code has been borrowed from the Apache Xerces project. We're copying the code to
   * keep from adding a dependency on Xerces in the Geronimo kernel.
   */
  
  package org.apache.geronimo.system.configuration;
  
  import java.io.Writer;
  import java.io.StringWriter;
  import java.io.IOException;
  
  
  /**
   * The printer is responsible for sending text to the output stream
   * or writer. This class performs direct writing for efficiency.
   * {@link IndentPrinter} supports indentation and line wrapping by
   * extending this class.
   *
   * @version $Revision: 410741 $ $Date: 2006-05-31 21:35:48 -0700 (Wed, 31 May 2006) $
   * @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>
   */
  public class Printer
  {
  
  
      /**
       * The output format associated with this serializer. This will never
       * be a null reference. If no format was passed to the constructor,
       * the default one for this document type will be used. The format
       * object is never changed by the serializer.
       */
      protected final OutputFormat format;
  
  
      /**
       * The writer to which the document is written.
       */
      protected Writer             writer;
  
  
      /**
       * The DTD writer. When we switch to DTD mode, all output is
       * accumulated in this DTD writer. When we switch out of it,
       * the output is obtained as a string. Must not be reset to
       * null until we're done with the document.
       */
      protected StringWriter       dtdWriter;
  
  
      /**
       * Holds a reference to the document writer while we are
       * in DTD mode.
       */
      protected Writer          docWriter;
  
  
      /**
       * Holds the exception thrown by the serializer.  Exceptions do not cause
       * the serializer to quit, but are held and one is thrown at the end.
       */
      protected IOException     exception;
  
  
      /**
       * The size of the output buffer.
       */
      private static final int BufferSize = 4096;
  
  
      /**
       * Output buffer.
       */
      private final char[]  buffer = new char[ BufferSize ];
  
  
      /**
       * Position within the output buffer.
       */
      private int           pos = 0;
  
  
      public Printer( Writer writer, OutputFormat format)
     {
         this.writer = writer;
         this.format = format;
         exception = null;
         dtdWriter = null;
         docWriter = null;
         pos = 0;
     }
 
 
     public IOException getException()
     {
         return exception;
     }
 
 
     /**
      * Called by any of the DTD handlers to enter DTD mode.
      * Once entered, all output will be accumulated in a string
      * that can be printed as part of the document's DTD.
      * This method may be called any number of time but will only
      * have affect the first time it's called. To exist DTD state
      * and get the accumulated DTD, call {@link #leaveDTD}.
      */
     public void enterDTD()
         throws IOException
     {
         // Can only enter DTD state once. Once we're out of DTD
         // state, can no longer re-enter it.
         if ( dtdWriter == null ) {
         flushLine( false );
 
             dtdWriter = new StringWriter();
             docWriter = writer;
             writer = dtdWriter;
         }
     }
 
 
     /**
      * Called by the root element to leave DTD mode and if any
      * DTD parts were printer, will return a string with their
      * textual content.
      */
     public String leaveDTD()
         throws IOException
     {
         // Only works if we're going out of DTD mode.
         if ( writer == dtdWriter ) {
         flushLine( false );
 
             writer = docWriter;
             return dtdWriter.toString();
         } else
             return null;
     }
 
 
     public void printText( String text )
         throws IOException
     {
         try {
             int length = text.length();
             for ( int i = 0 ; i < length ; ++i ) {
                 if ( pos == BufferSize ) {
                     writer.write( buffer );
                     pos = 0;
                 }
                 buffer[ pos ] = text.charAt( i );
                 ++pos;
             }
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void printText( StringBuffer text )
         throws IOException
     {
         try {
             int length = text.length();
             for ( int i = 0 ; i < length ; ++i ) {
                 if ( pos == BufferSize ) {
                     writer.write( buffer );
                     pos = 0;
                 }
                 buffer[ pos ] = text.charAt( i );
                 ++pos;
             }
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void printText( char[] chars, int start, int length )
         throws IOException
     {
         try {
             while ( length-- > 0 ) {
                 if ( pos == BufferSize ) {
                     writer.write( buffer );
                     pos = 0;
                 }
                 buffer[ pos ] = chars[ start ];
                 ++start;
                 ++pos;
             }
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void printText( char ch )
         throws IOException
     {
         try {
             if ( pos == BufferSize ) {
                 writer.write( buffer );
                 pos = 0;
             }
             buffer[ pos ] = ch;
             ++pos;
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void printSpace()
         throws IOException
     {
         try {
             if ( pos == BufferSize ) {
                 writer.write( buffer );
                 pos = 0;
             }
             buffer[ pos ] = ' ';
             ++pos;
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void breakLine()
         throws IOException
     {
         try {
             if ( pos == BufferSize ) {
                 writer.write( buffer );
                 pos = 0;
             }
             buffer[ pos ] = '\n';
             ++pos;
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
     }
 
 
     public void breakLine( boolean preserveSpace )
         throws IOException
     {
         breakLine();
     }
 
 
     public void flushLine( boolean preserveSpace )
         throws IOException
     {
         // Write anything left in the buffer into the writer.
         try {
             writer.write( buffer, 0, pos );
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
         }
         pos = 0;
     }
 
 
     /**
      * Flush the output stream. Must be called when done printing
      * the document, otherwise some text might be buffered.
      */
     public void flush()
         throws IOException
     {
         try {
             writer.write( buffer, 0, pos );
             writer.flush();
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
             throw except;
         }
         pos = 0;
     }
 
 
     public void indent()
     {
         // NOOP
     }
 
 
     public void unindent()
     {
         // NOOP
     }
 
 
     public int getNextIndent()
     {
         return 0;
     }
 
 
     public void setNextIndent( int indent )
     {
     }
 
 
     public void setThisIndent( int indent )
     {
     }
 
 
 }