AutoSpellChecker.java

AutoSpellChecker.java

/*
 *  Based on JOrtho 05.11.2005, by i-net software (GNU General Public License)
 */
package com.inet.jortho;

import java.util.Locale;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.text.Highlighter.Highlight;

/**
 * This class check a <code>JTextComponent</code> automatically (in the background) for orthography. Spell error are
 * highlighted with a red zigzag line.
 * 
 * @author Volker Berlin
 */
class AutoSpellChecker implements DocumentListener, LanguageChangeListener {
    private static final RedZigZagPainter painter = new RedZigZagPainter();
    private final JTextComponent                jText;
    private final SpellCheckerOptions options;
    private Dictionary                    dictionary;
    private Locale                        locale;
    
    public AutoSpellChecker(JTextComponent text, SpellCheckerOptions options){
        this.jText = text;
        this.options = options == null ? SpellChecker.getOptions() : options;
        jText.getDocument().addDocumentListener( this );

        SpellChecker.addLanguageChangeLister( this );
        dictionary = SpellChecker.getCurrentDictionary();
        locale = SpellChecker.getCurrentLocale();
    }

    /**
     * Check the Elements on the given position.
     */
    public void checkElements( int offset, int length ) {
        int end = offset + length;
        Document document = jText.getDocument();
        Element element;

        do{
            try {
                // We need to use a ParagraphElement because a CharacterElement produce problems with formating in a word
                element = ((AbstractDocument)document).getParagraphElement( offset );
            } catch( java.lang.Exception ex ) {
                return;
            }
            checkElement( element );
            int endOffset = element.getEndOffset();
            offset = endOffset > offset ? endOffset : offset + 1;
        }while( offset <= end && offset < document.getLength() );
    }

    /**
     * Check the spelling of the text of an element.
     * 
     * @param element
     *            the to checking Element
     */
    private void checkElement( javax.swing.text.Element element ) {
        try {
            int i = element.getStartOffset();
            int j = element.getEndOffset();
            Highlighter highlighter = jText.getHighlighter();
            Highlight[] highlights = highlighter.getHighlights();
            for( int k = highlights.length; --k >= 0; ) {
                Highlight highlight = highlights[k];
                int hlStartOffset = highlight.getStartOffset();
                int hlEndOffset = highlight.getEndOffset();
                if( (i <= hlStartOffset && hlStartOffset <= j) || 
                    (i <= hlEndOffset && hlEndOffset <= j) ) {
                    if( highlight.getPainter() == painter ) {
                        highlighter.removeHighlight( highlight );
                    }
                }
            }

            int l = ((AbstractDocument)jText.getDocument()).getLength();
            j = Math.min( j, l );
            if( i >= j )
                return;

            // prevent a NPE if the dictionary is currently not loaded.
            Dictionary dic = dictionary;
            Locale loc = locale;
            if( dic == null || loc == null ){
                return;
            }
            
            Tokenizer tok = new Tokenizer( jText, dic, loc, i, j, options );
            String word;
            while( (word = tok.nextInvalidWord()) != null ) {
                int wordOffset = tok.getWordOffset();
                highlighter.addHighlight( wordOffset, wordOffset + word.length(), painter );
            }
        } catch( BadLocationException e ) {
        	SpellChecker.getMessageHandler().handleException( e );
        }
    }
}