/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2002,2004 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.

 */

package com.sun.org.apache.xml.internal.serialize;

import java.io.Writer;

import java.io.StringWriter;

import java.io.IOException;

/**

 * Extends {@link Printer} and adds support for indentation and line

 * wrapping.

 *

 * @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;

    public 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.toString() );

    }

    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 _line is empty and _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;

    }

}