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Groovy example source code file (GroovyFilter.java)

This example Groovy source code file (GroovyFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

auto_tab_action, autotabaction, awt, d, element, event, groovyfilter, gui, jtextcomponent, segment, segment, string, string, style, style, styleddocument, styleddocument, swing, text

The Groovy GroovyFilter.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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 groovy.ui.text;

import java.awt.Color;

import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.KeyStroke;

import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.Element;
import javax.swing.text.JTextComponent;
import javax.swing.text.Segment;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;
import javax.swing.text.StyleContext;


/**
 * @author Evan "Hippy" Slatis
 */
public class GroovyFilter extends StructuredSyntaxDocumentFilter {

    // java tab policy action
    private static final Action AUTO_TAB_ACTION = new AutoTabAction();

    // Style names
    public static final String COMMENT = "comment";
    public static final String SLASH_STAR_COMMENT = "/\\*(?s:.)*?(?:\\*/|\\z)";
    public static final String SLASH_SLASH_COMMENT = "//.*";
    public static final String QUOTES =
            "(?ms:\"{3}(?!\\\"{1,3}).*?(?:\"{3}|\\z))|(?:\"{1}(?!\\\").*?(?:\"|\\Z))";
    public static final String SINGLE_QUOTES =
            "(?ms:'{3}(?!'{1,3}).*?(?:'{3}|\\z))|(?:'[^'].*?(?:'|\\z))";
    public static final String SLASHY_QUOTES = "(?:/[^/*].*?/|(?ms:\\$/.*?(?:/\\$|\\z)))";
    public static final String DIGIT = "\\d+?[efld]?";

    public static final String IDENT = "[\\w\\$&&[\\D]][\\w\\$]*";
    public static final String OPERATION = "[\\w\\$&&[\\D]][\\w\\$]* *\\(";
    public static final String LEFT_PARENS = "\\(";

    private static final Color COMMENT_COLOR =
            Color.LIGHT_GRAY.darker().darker();


    public static final String RESERVED_WORD = "reserved";
    public static final String[] RESERVED_WORDS = {"\\babstract\\b",
            "\\bassert\\b",
            "\\bdefault\\b",
            "\\bif\\b",
            "\\bprivate\\b",
            "\\bthis\\b",
            "\\bboolean\\b",
            "\\bdo\\b",
            "\\bimplements\\b",
            "\\bprotected\\b",
            "\\bthrow\\b",
            "\\bbreak\\b",
            "\\bdouble\\b",
            "\\bimport\\b",
            "\\bpublic\\b",
            "\\bthrows\\b",
            "\\bbyte\\b",
            "\\belse\\b",
            "\\binstanceof\\b",
            "\\breturn\\b",
            "\\btransient\\b",
            "\\bcase\\b",
            "\\bextends\\b",
            "\\bint\\b",
            "\\bshort\\b",
            "\\btry\\b",
            "\\bcatch\\b",
            "\\bfinal\\b",
            "\\binterface\\b",
            "\\benum\\b",
            "\\bstatic\\b",
            "\\bvoid\\b",
            "\\bchar\\b",
            "\\bfinally\\b",
            "\\blong\\b",
            "\\bstrictfp\\b",
            "\\bvolatile\\b",
            "\\bclass\\b",
            "\\bfloat\\b",
            "\\bnative\\b",
            "\\bsuper\\b",
            "\\bwhile\\b",
            "\\bconst\\b",
            "\\bfor\\b",
            "\\bnew\\b",
            "\\bswitch\\b",
            "\\bcontinue\\b",
            "\\bgoto\\b",
            "\\bpackage\\b",
            "\\bdef\\b",
            "\\bas\\b",
            "\\bin\\b",
            "\\bsynchronized\\b",
            "\\bnull\\b"};

    /**
     * Creates a new instance of GroovyFilter
     */
    public GroovyFilter(DefaultStyledDocument doc) {
        super(doc);
        init();
    }

    private void init() {
        StyleContext styleContext = StyleContext.getDefaultStyleContext();
        Style defaultStyle = styleContext.getStyle(StyleContext.DEFAULT_STYLE);

        Style comment = styleContext.addStyle(COMMENT, defaultStyle);
        StyleConstants.setForeground(comment, COMMENT_COLOR);
        StyleConstants.setItalic(comment, true);

        Style quotes = styleContext.addStyle(QUOTES, defaultStyle);
        StyleConstants.setForeground(quotes, Color.MAGENTA.darker().darker());

        Style charQuotes = styleContext.addStyle(SINGLE_QUOTES, defaultStyle);
        StyleConstants.setForeground(charQuotes, Color.GREEN.darker().darker());

        Style slashyQuotes = styleContext.addStyle(SLASHY_QUOTES, defaultStyle);
        StyleConstants.setForeground(slashyQuotes, Color.ORANGE.darker());

        Style digit = styleContext.addStyle(DIGIT, defaultStyle);
        StyleConstants.setForeground(digit, Color.RED.darker());

        Style operation = styleContext.addStyle(OPERATION, defaultStyle);
        StyleConstants.setBold(operation, true);

        Style ident = styleContext.addStyle(IDENT, defaultStyle);

        Style reservedWords = styleContext.addStyle(RESERVED_WORD, defaultStyle);
        StyleConstants.setBold(reservedWords, true);
        StyleConstants.setForeground(reservedWords, Color.BLUE.darker().darker());

        Style leftParens = styleContext.addStyle(IDENT, defaultStyle);

        getRootNode().putStyle(SLASH_STAR_COMMENT, comment);
        getRootNode().putStyle(SLASH_SLASH_COMMENT, comment);
        getRootNode().putStyle(QUOTES, quotes);
        getRootNode().putStyle(SINGLE_QUOTES, charQuotes);
        getRootNode().putStyle(SLASHY_QUOTES, slashyQuotes);
        getRootNode().putStyle(DIGIT, digit);

        getRootNode().putStyle(OPERATION, operation);
        StructuredSyntaxDocumentFilter.LexerNode node = createLexerNode();
        node.putStyle(RESERVED_WORDS, reservedWords);
        node.putStyle(LEFT_PARENS, leftParens);
        getRootNode().putChild(OPERATION, node);

        getRootNode().putStyle(IDENT, ident);
        node = createLexerNode();
        node.putStyle(RESERVED_WORDS, reservedWords);
        getRootNode().putChild(IDENT, node);
    }

    public static void installAutoTabAction(JTextComponent tComp) {
        tComp.getActionMap().put("GroovyFilter-autoTab", AUTO_TAB_ACTION);
        KeyStroke keyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, false);
        tComp.getInputMap().put(keyStroke, "GroovyFilter-autoTab");
    }

    private static class AutoTabAction extends AbstractAction {

        private StyledDocument doc;
        private final Segment segment = new Segment();
        private final StringBuffer buffer = new StringBuffer();

        public void actionPerformed(ActionEvent ae) {
            JTextComponent tComp = (JTextComponent) ae.getSource();
            if (tComp.getDocument() instanceof StyledDocument) {
                doc = (StyledDocument) tComp.getDocument();
                try {
                    doc.getText(0, doc.getLength(), segment);
                }
                catch (Exception e) {
                    // should NEVER reach here
                    e.printStackTrace();
                }
                int offset = tComp.getCaretPosition();
                int index = findTabLocation(offset);
                buffer.delete(0, buffer.length());
                buffer.append('\n');
                if (index > -1) {
                    for (int i = 0; i < index + 4; i++) {
                        buffer.append(' ');
                    }
                }
                try {
                    doc.insertString(offset, buffer.toString(),
                            doc.getDefaultRootElement().getAttributes());
                }
                catch (BadLocationException ble) {
                    ble.printStackTrace();
                }
            }
        }

        public int findTabLocation(int offset) {

            // find first {
            boolean cont = true;
            while (offset > -1 && cont) {
                Element el = doc.getCharacterElement(offset);
                Object color =
                        el.getAttributes().getAttribute(StyleConstants.Foreground);
                if (!COMMENT_COLOR.equals(color)) {
                    cont = segment.array[offset] != '{' &&
                            segment.array[offset] != '}';
                }
                offset -= cont ? 1 : 0;
            }

            if (offset > -1 && segment.array[offset] == '{') {
                while (offset > -1 &&
                        !Character.isWhitespace(segment.array[offset--])) {
                }
            }

            int index = offset < 0 || segment.array[offset] == '}' ? -4 : 0;
            if (offset > -1) {
                Element top = doc.getDefaultRootElement();
                offset = top.getElement(top.getElementIndex(offset)).getStartOffset();

                while (Character.isWhitespace(segment.array[offset++])) {
                    index++;
                }
            }

            return index;
        }
    }
}

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