Groovy example source code file (StructuredSyntaxDocumentFilter.java)

This example Groovy source code file (StructuredSyntaxDocumentFilter.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

attributeset, badlocationexception, badlocationexception, io, lexernode, lexernode, mlcomparator, multilinerun, multilinerun, nio, position, regex, sortedset, string, string, structuredsyntaxdocumentfilter, style, text, util

The Groovy StructuredSyntaxDocumentFilter.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 javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.DocumentFilter;
import javax.swing.text.Position;
import javax.swing.text.Segment;
import javax.swing.text.Style;
import javax.swing.text.StyleContext;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 *
 * @author Evan "Hippy" Slatis
 */
public class StructuredSyntaxDocumentFilter extends DocumentFilter {
    
    public static final String TAB_REPLACEMENT = "    ";
    
    private static final MLComparator ML_COMPARATOR = new MLComparator();

    /**
     * The root of the lexical parsing tree.
     */
    protected LexerNode lexer = new LexerNode(true);
    
    // The styled document the filter parses
    protected DefaultStyledDocument styledDocument; 
    
    // the document buffer and segment
    private Segment segment = new Segment();
    private CharBuffer buffer;
    
    /**
     * The position tree of multi-line comments.
     */ 
    protected SortedSet mlTextRunSet = new TreeSet(ML_COMPARATOR);
    
    // Ensures not adding any regexp with capturing groups
    private static void checkRegexp(String regexp) {
        String checking = regexp.replaceAll("\\\\\\(", "X").replaceAll("\\(\\?", "X");
        int checked = checking.indexOf('(');
        if (checked > -1) {
            String msg = "Only non-capturing groups allowed:\r\n" +
                         regexp + "\r\n";
            for (int i = 0; i < checked; i++) {
                msg += " ";
            }
            msg += "^";
            throw new IllegalArgumentException(msg);
        }
    }
    
    /**
     * Creates a new instance of StructuredSyntaxDocumentFilter
     * @param document the styled document to parse
     */
    public StructuredSyntaxDocumentFilter(DefaultStyledDocument document) {
        this.styledDocument = document;
    }
    
    private int calcBeginParse(int offset) {
        MultiLineRun mlr = getMultiLineRun(offset);
        if (mlr != null) {
            // means we're in middle of mlr, so start at beginning of mlr
            offset = mlr.start();
        }
        else {
            // otherwise, earliest position in line not part of mlr
            offset = styledDocument.getParagraphElement(offset).getStartOffset();
            mlr = getMultiLineRun(offset);
            offset = mlr == null ? offset : mlr.end() + 1;
        }
        
        return offset;
    }
    
    private int calcEndParse(int offset) {
        MultiLineRun mlr = getMultiLineRun(offset);
        if (mlr != null) {
            // means we're in middle of mlr, so end is at end of mlr
            offset = mlr.end();
        }
        else {
            // otherwise, latest position in line not part of mlr
            offset = styledDocument.getParagraphElement(offset).getEndOffset();
            mlr = getMultiLineRun(offset);
            offset = mlr == null ? offset : mlr.end();
        }
        
        return offset;
    }
    
    /**
     * Create a new LexerNode for adding to root.
     *
     * @return a new LexerNode
     */
    public LexerNode createLexerNode() {
        return new LexerNode(false);
    }
    
    // given an offset, return the mlr it resides in
    private MultiLineRun getMultiLineRun(int offset) {
        MultiLineRun ml = null;
        if (offset > 0) {
            Integer os = Integer.valueOf(offset);

            SortedSet set = mlTextRunSet.headSet(os);
            if (!set.isEmpty()) {
                ml = (MultiLineRun)set.last();
                ml = ml.end() >= offset ? ml : null;
            }
        }

        return ml;
    }
    
    /**
     * Get the root node for lexing the document.   Children can be added such
     * that matching patterns can be further parsed if required.
     *
     * @return the root lexing node.  
     */
    public LexerNode getRootNode() {
        return lexer;
    }
    
    /**
     * Insert a string into the document, and then parse it if the parser has been
     * set.
     *
     * @param fb
     * @param offset
     * @param text
     * @param attrs
     * @throws BadLocationException
     */    
    public void insertString(DocumentFilter.FilterBypass fb, int offset,
                             String text, AttributeSet attrs)
        throws BadLocationException {
        // remove problem meta characters returns
        text = replaceMetaCharacters(text);
        
        fb.insertString(offset, text, attrs);
        
        // start on the string that was inserted
        parseDocument(offset, text.length());
    }
    
    /**
     * Parse the Document to update the character styles given an initial start
     * position.  Called by the filter after it has updated the text. 
     *
     * @param offset
     * @param length
     * @throws BadLocationException
     */
    protected void parseDocument(int offset, int length) throws BadLocationException {
        // initialize the segment with the complete document so the segment doesn't
        // have an underlying gap in the buffer
        styledDocument.getText(0, styledDocument.getLength(), segment);
        
        buffer = CharBuffer.wrap(segment.array).asReadOnlyBuffer();
        
        // initialize the lexer if necessary
        if (!lexer.isInitialized()) {
            // prime the parser and reparse whole document
            lexer.initialize();
            offset = 0;
            length = styledDocument.getLength();
        }
        else {
            int end = offset + length;
            offset = calcBeginParse(offset);
            length = calcEndParse(end) - offset;
            
            // clean the tree by ensuring multi line styles are reset in area
            // of parsing
            SortedSet set = mlTextRunSet.subSet(Integer.valueOf(offset),
                                                Integer.valueOf(offset + length));
            if (set != null) {
                set.clear();
            }
        }
        
        // parse the document
        lexer.parse(buffer, offset, length);
    }

    /**
     * Remove a string from the document, and then parse it if the parser has been
     * set.
     *
     * @param fb
     * @param offset
     * @param length
     * @throws BadLocationException
     */    
    public void remove(DocumentFilter.FilterBypass fb, int offset, int length)
        throws BadLocationException {
        // FRICKIN' HACK!!!!! For some reason, deleting a string at offset 0
        // does not get done properly, so first replace and remove after parsing
        if (offset == 0 && length != fb.getDocument().getLength()) {
            fb.replace(0, length, "\n", lexer.defaultStyle);
            
            // start on either side of the removed text
            parseDocument(offset, 2);
            fb.remove(offset, 1);
        }
        else {
            fb.remove(offset, length);
            
            // start on either side of the removed text
            if (offset + 1 < fb.getDocument().getLength()) {
                parseDocument(offset, 1);
            }
            else if (offset - 1 > 0) {
                parseDocument(offset - 1, 1);
            }
            else {
                // empty text
                mlTextRunSet.clear();
            }
        }

    }

    /**
     * Replace a string in the document, and then parse it if the parser has been
     * set.
     *
     * @param fb
     * @param offset
     * @param length
     * @param text
     * @param attrs
     * @throws BadLocationException
     */    
    public void replace(DocumentFilter.FilterBypass fb, int offset, 
                        int length, String text, AttributeSet attrs)
        throws BadLocationException {
        // remove problem meta characters returns
        text = replaceMetaCharacters(text);
        
        fb.replace(offset, length, text, attrs);
        
        // start on the text that was replaced
        parseDocument(offset, text.length());
    }
    
    // tabs with spaces (I hate tabs)
    private String replaceMetaCharacters(String string) {
        // just in case remove carriage returns
        string = string.replaceAll("\\t", TAB_REPLACEMENT);
        return string;
    }
    
    public final class LexerNode {
        
        private Style defaultStyle;
    
        private Map styleMap = new LinkedHashMap();
        private Map children = new HashMap();

        private Matcher matcher;
        private List groupList = new ArrayList();
        
        private boolean initialized;
        
        private CharBuffer lastBuffer;

        /*
         * Creates a new instance of LexerNode 
         */
        LexerNode(boolean isParent) {
            StyleContext sc = StyleContext.getDefaultStyleContext();
            defaultStyle = sc.getStyle(StyleContext.DEFAULT_STYLE);
        }
    
        private String buildRegexp(String[] regexps) {
            String regexp = "";

            for (int i = 0; i < regexps.length; i++) {
                regexp += "|" + regexps[i];
            }

            // ensure leading '|' is removed
            return regexp.substring(1);
        }
        
        public Style getDefaultStyle() {
            return defaultStyle;
        }

        private void initialize() {
            matcher = null;
            groupList.clear();
            groupList.add(null);
            
            Iterator iter = styleMap.keySet().iterator();
            String regexp = "";
            while (iter.hasNext()) {
                String nextRegexp = (String)iter.next();
                regexp += "|(" + nextRegexp + ")";
                // have to compile regexp first so that it will match
                groupList.add(Pattern.compile(nextRegexp).pattern());
            }
            if (!regexp.equals("")) {
                matcher = Pattern.compile(regexp.substring(1)).matcher("");
                
                iter = children.values().iterator();
                while (iter.hasNext()) {
                    ((LexerNode)iter.next()).initialize();
                }
            }
            initialized = true;
        }
        
        /**
         * @return true if initialised
         */        
        public boolean isInitialized() {
            return initialized;
        }

        /**
         * @param buffer
         * @param offset
         * @param length
         * @throws BadLocationException
         */        
        public void parse(CharBuffer buffer, int offset, int length)
            throws BadLocationException {
            // get the index of where we can start to look for an exit:
            // i.e. after the end of the length of the segment, when we find 
            // that text in question already is set properly, we can stop
            // parsing
            int checkPoint = offset + length;
            
            // reset the matcher and start parsing string
            if (lastBuffer != buffer) {
                matcher.reset(buffer);
                lastBuffer = buffer;
            }
            
            // the start and end indices of a match in the Matcher looking
            int matchEnd = offset;
            Style style = null;
            while (matchEnd < checkPoint && matcher.find(offset)) {
                // when we get something other than -1, we know which regexp
                // matched; the 0 group is the complete expression of the 
                // matcher, which would always return a hit based on the above
                // while condition
                int groupNum = 0;
                while ((offset = matcher.start(++groupNum)) == -1){
                }
                
                // if the matching offset is not the same as the end of the 
                // previous match, we have extra text not matched, so set to 
                // the default style of this lexer node
                if (offset != matchEnd) {
                    offset = offset > checkPoint ? checkPoint : offset; 
                    styledDocument.setCharacterAttributes(matchEnd,
                                                          offset - matchEnd,
                                                          defaultStyle,
                                                          true);
                    if (offset >= checkPoint) {
                        return;
                    }
                }

                // track the end of the matching string 
                matchEnd = matcher.end(groupNum);

                // retrieve the proper style from groupNum of the groupList and
                // styleMap, then set the attributes of the matching string
                style = (Style)styleMap.get((String)groupList.get(groupNum));
                styledDocument.setCharacterAttributes(offset,
                                                      matchEnd - offset,
                                                      style, true);

                // if the match was multiline, which we'll know if they span
                // multiple paragraph elements, the mark it (this list was cleaned
                // above in parseDocument())
                if (styledDocument.getParagraphElement(offset).getStartOffset() !=
                    styledDocument.getParagraphElement(matchEnd).getStartOffset()) {
                    // mark a ml run
                    MultiLineRun mlr = new MultiLineRun(offset, matchEnd);
                    mlTextRunSet.add(mlr);
                }
                
                // parse the child regexps, if any, within a matched block
                LexerNode node = (LexerNode)children.get(groupList.get(groupNum));
                if (node != null) {
                    node.parse(buffer, offset, matchEnd - offset);
                }
                
                // set the offset to start where we left off
                offset = matchEnd;
            }
            if (matchEnd < checkPoint) {
                // if we finished before hitting the end of the checkpoint from
                // no mroe matches, then set ensure the text is reset to the
                // defaultStyle
                styledDocument.setCharacterAttributes(matchEnd,
                                                      checkPoint - matchEnd,
                                                      defaultStyle,
                                                      true);
            }
        }

        /**
         *
         * @param regexp
         * @param node
         */        
        public void putChild(String regexp, LexerNode node) {
            node.defaultStyle = (Style)styleMap.get(regexp);
            
            // have to compile regexp first so that it will match
            children.put(Pattern.compile(regexp).pattern(), node);
            initialized = false;
        }

        /**
         * @param regexps
         * @param node
         */        
        public void putChild(String[] regexps, LexerNode node) {
            putChild(buildRegexp(regexps), node);
        }

        /**
         * @param regexp
         * @param style
         */        
        public void putStyle(String regexp, Style style) {
            checkRegexp(regexp);
            styleMap.put(regexp, style);
            initialized = false;
        }

        /**
         * @param regexps
         * @param style
         */        
        public void putStyle(String regexps[], Style style) {
            putStyle(buildRegexp(regexps), style);
        }

        /**
         * @param regexp
         */        
        public void removeChild(String regexp) {
            children.remove(regexp);
        }

        /**
         * @param regexp
         */        
        public void removeStyle(String regexp) {
            styleMap.remove(regexp);
            children.remove(regexp);
        }

        /**
         * @param regexps
         */        
        public void removeStyle(String regexps[]) {
            removeStyle(buildRegexp(regexps));
        }
        
        public void setDefaultStyle(Style style) {
            defaultStyle = style;
        }
    }
    
    protected class MultiLineRun {
        
        private Position start;
        private Position end;
        private int delimeterSize;
        
        public MultiLineRun(int start, int end) throws BadLocationException {
            this(start, end, 2);
        }
        
        public MultiLineRun(int start, int end, int delimeterSize) throws BadLocationException {
            if (start > end) {
                String msg = "Start offset is after end: ";
                throw new BadLocationException(msg, start);
            }
            if (delimeterSize < 1) {
                String msg = "Delimiters be at least size 1: " + 
                              delimeterSize;
                throw new IllegalArgumentException(msg);
            }
            this.start = styledDocument.createPosition(start);
            this.end = styledDocument.createPosition(end);
            this.delimeterSize = delimeterSize;
        }
        
        public int getDelimeterSize() {
            return delimeterSize;
        }
        
        public int end() {
            return end.getOffset();
        }
        
        public int length() {
            return end.getOffset() - start.getOffset();
        }
        
        public int start() {
            return start.getOffset();
        }
        
        public String toString() {
            return start.toString() + " " + end.toString();
        }
        
    }

    private static class MLComparator implements Comparator {
        
        public int compare(Object obj, Object obj1) {
            return valueOf(obj) - valueOf(obj1);
        }
        
        private int valueOf(Object obj) {
            return obj instanceof Integer ? 
                    ((Integer)obj).intValue() : 
                    (obj instanceof MultiLineRun) ?
                        ((MultiLineRun)obj).start() :
                        ((Position)obj).getOffset();
        }
    }
}