/**
    *
    * 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;
  
  
  /**
   * Extends {@link Printer} and adds support for indentation and line
   * wrapping.
   *
   * @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 IndentPrinter
      extends Printer
  {
  
  
      /**
       * Holds the currently accumulating text line. This buffer will constantly
       * be reused by deleting its contents instead of reallocating it.
       */
      private StringBuffer    _line;
  
  
      /**
       * Holds the currently accumulating text that follows {@link #_line}.
       * When the end of the part is identified by a call to {@link #printSpace}
       * or {@link #breakLine}, this part is added to the accumulated line.
       */
      private StringBuffer    _text;
  
  
      /**
       * Counts how many white spaces come between the accumulated line and the
       * current accumulated text. Multiple spaces at the end of the a line
       * will not be printed.
       */
      private int             _spaces;
  
  
      /**
       * Holds the indentation for the current line that is now accumulating in
       * memory and will be sent for printing shortly.
       */
      private int             _thisIndent;
      
      
      /**
       * Holds the indentation for the next line to be printed. After this line is
       * printed, {@link #_nextIndent} is assigned to {@link #_thisIndent}.
       */
      private int             _nextIndent;
  
  
      IndentPrinter( Writer writer, OutputFormat format)
      {
          super( writer, format );
          // Initialize everything for a first/second run.
          _line = new StringBuffer( 80 );
          _text = new StringBuffer( 20 );
          _spaces = 0;
          _thisIndent = _nextIndent = 0;
      }
  
  
      /**
       * 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()
      {
         // Can only enter DTD state once. Once we're out of DTD
         // state, can no longer re-enter it.
         if ( dtdWriter == null ) {
             _line.append( _text );
             _text = new StringBuffer( 20 );
             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()
     {
         // Only works if we're going out of DTD mode.
         if ( writer == dtdWriter ) {
             _line.append( _text );
             _text = new StringBuffer( 20 );
             flushLine( false );
             writer = docWriter;
             return dtdWriter.toString();
         } else
             return null;
     }
     
     
     /**
      * Called to print additional text. Each time this method is called
      * it accumulates more text. When a space is printed ({@link
      * #printSpace}) all the accumulated text becomes one part and is
      * added to the accumulate line. When a line is long enough, it can
      * be broken at its text boundary.
      *
      * @param text The text to print
      */
     public void printText( String text )
     {
         _text.append( text );
     }
     
     
     public void printText( StringBuffer text )
     {
         _text.append( text );
     }
 
 
     public void printText( char ch )
     {
         _text.append( ch );
     }
 
 
     public void printText( char[] chars, int start, int length )
     {
         _text.append( chars, start, length );
     }
     
 
     /**
      * Called to print a single space between text parts that may be
      * broken into separate lines. Must not be called to print a space
      * when preserving spaces. The text accumulated so far with {@link
      * #printText} will be added to the accumulated line, and a space
      * separator will be counted. If the line accumulated so far is
      * long enough, it will be printed.
      */
     public void printSpace()
     {
         // The line consists of the text accumulated in _line,
         // followed by one or more spaces as counted by _spaces,
         // followed by more space accumulated in _text:
         // -  Text is printed and accumulated into _text.
         // -  A space is printed, so _text is added to _line and
         //    a space is counted.
         // -  More text is printed and accumulated into _text.
         // -  A space is printed, the previous spaces are added
         //    to _line, the _text is added to _line, and a new
         //    space is counted.
         
         // If text was accumulated with printText(), then the space
         // means we have to move that text into the line and
         // start accumulating new text with printText().
         if ( _text.length() > 0 ) {
             // If the text breaks a line bounary, wrap to the next line.
             // The printed line size consists of the indentation we're going
             // to use next, the accumulated line so far, some spaces and the
             // accumulated text so far.
             if ( format.getLineWidth() > 0 &&
                  _thisIndent + _line.length() + _spaces + _text.length() > format.getLineWidth() ) {
                 flushLine( false );
                 try {
                     // Print line and new line, then zero the line contents.
                     writer.write( format.getLineSeparator() );
                 } catch ( IOException except ) {
                     // We don't throw an exception, but hold it
                     // until the end of the document.
                     if ( exception == null )
                         exception = except;
                 }
             }
             
             // Add as many spaces as we accumulaed before.
             // At the end of this loop, _spaces is zero.
             while ( _spaces > 0 ) {
                 _line.append( ' ' );
                 --_spaces;
             }
             _line.append( _text );
             _text = new StringBuffer( 20 );
         }
         // Starting a new word: accumulate the text between the line
         // and this new word; not a new word: just add another space.
         ++_spaces;
     }
 
 
     /**
      * Called to print a line consisting of the text accumulated so
      * far. This is equivalent to calling {@link #printSpace} but
      * forcing the line to print and starting a new line ({@link
      * #printSpace} will only start a new line if the current line
      * is long enough).
      */
     public void breakLine()
     {
         breakLine( false );
     }
 
 
     public void breakLine( boolean preserveSpace )
     {
         // Equivalent to calling printSpace and forcing a flushLine.
         if ( _text.length() > 0 ) {
             while ( _spaces > 0 ) {
                 _line.append( ' ' );
                 --_spaces;
             }
             _line.append( _text );
             _text = new StringBuffer( 20 );
         }
         flushLine( preserveSpace );
         try {
             // Print line and new line, then zero the line contents.
             writer.write( format.getLineSeparator() );
         } catch ( IOException except ) {
             // We don't throw an exception, but hold it
             // until the end of the document.
             if ( exception == null )
                 exception = except;
         }
     }
     
 
     /**
      * Flushes the line accumulated so far to the writer and get ready
      * to accumulate the next line. This method is called by {@link
      * #printText} and {@link #printSpace} when the accumulated line plus
      * accumulated text are two long to fit on a given line. At the end of
      * this method {@link #_line} is empty and {@link #_spaces} is zero.
      */
     public void flushLine( boolean preserveSpace )
     {
         int     indent;
         
         if ( _line.length() > 0 ) {
             try {
                 
                 if ( format.getIndenting() && ! preserveSpace ) {
                     // Make sure the indentation does not blow us away.
                     indent = _thisIndent;
                     if ( ( 2 * indent ) > format.getLineWidth() && format.getLineWidth() > 0 )
                         indent = format.getLineWidth() / 2;
                     // Print the indentation as spaces and set the current
                     // indentation to the next expected indentation.
                     while ( indent > 0 ) {
                         writer.write( ' ' );
                         --indent;
                     }
                 }
                 _thisIndent = _nextIndent;
                 
                 // There is no need to print the spaces at the end of the line,
                 // they are simply stripped and replaced with a single line
                 // separator.
                 _spaces = 0;
                 writer.write( _line.toString() );
                 
                 _line = new StringBuffer( 40 );
             } catch ( IOException except ) {
                 // We don't throw an exception, but hold it
                 // until the end of the document.
                 if ( exception == null )
                     exception = except;
             }
         }
     }
     
     
     /**
      * Flush the output stream. Must be called when done printing
      * the document, otherwise some text might be buffered.
      */
     public void flush()
     {
         if ( _line.length() > 0 || _text.length() > 0 )
             breakLine();
         try {
             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;
         }
     }
 
 
     /**
      * Increment the indentation for the next line.
      */
     public void indent()
     {
         _nextIndent += format.getIndent();
     }
 
 
     /**
      * Decrement the indentation for the next line.
      */
     public void unindent()
     {
         _nextIndent -= format.getIndent();
         if ( _nextIndent < 0 )
             _nextIndent = 0;
         // If there is no current line and we're de-identing then
         // this indentation level is actually the next level.
         if ( ( _line.length() + _spaces + _text.length() ) == 0 )
             _thisIndent = _nextIndent;
     }
 
 
     public int getNextIndent()
     {
         return _nextIndent;
     }
 
 
     public void setNextIndent( int indent )
     {
         _nextIndent = indent;
     }
 
 
     public void setThisIndent( int indent )
     {
         _thisIndent = indent;
     }
 
 
 }