Groovy example source code file (AntlrASTProcessSnippets.java)

This example Groovy source code file (AntlrASTProcessSnippets.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

antlrastprocessor, antlrastprocesssnippets, antlrastprocesssnippets, arraylist, arraylist, ast, ast, groovysourceast, iterator, linecolumn, linecolumn, list, util

The Groovy AntlrASTProcessSnippets.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 org.codehaus.groovy.antlr;

/**
 * Process to decorate antlr AST with ending line/col info, and if
 * possible the snipppet of source from the start/end line/col for each node.
 *
 * @author <a href="mailto:groovy@ross-rayner.com">Jeremy Rayner
 * @version $Revision: 21223 $
 */

import antlr.collections.AST;
import java.util.*;

public class AntlrASTProcessSnippets implements AntlrASTProcessor{

    public AntlrASTProcessSnippets() {
    }

    /**
     * decorate antlr AST with ending line/col info, and if
     * possible the snipppet of source from the start/end line/col for each node.
     * @param t the AST to decorate
     * @return the decorated AST
     */
    public AST process(AST t) {
        // first visit
        List l = new ArrayList();
        traverse((GroovySourceAST)t,l,null);

        //System.out.println("l:" + l);
        // second visit
        Iterator itr = l.iterator();
        if (itr.hasNext()) { itr.next(); /* discard first */ }
        traverse((GroovySourceAST)t,null,itr);
        return t;
    }

    /**
     * traverse an AST node
     * @param t the AST node to traverse
     * @param l A list to add line/col info to
     * @param itr An iterator over a list of line/col
     * @return A decorated AST node
     */
    private void traverse(GroovySourceAST t,List l,Iterator itr) {
         while (t != null) {
             // first visit of node
             if (l != null) {
                 l.add(new LineColumn(t.getLine(),t.getColumn()));
             }

             // second visit of node
             if (itr != null && itr.hasNext()) {
                 LineColumn lc = (LineColumn)itr.next();
                 if (t.getLineLast() == 0) {
                     int nextLine = lc.getLine();
                     int nextColumn = lc.getColumn();
                     if (nextLine < t.getLine() || (nextLine == t.getLine() && nextColumn < t.getColumn())) {
                         nextLine = t.getLine();
                         nextColumn = t.getColumn();
                     }
                     t.setLineLast(nextLine);
                     t.setColumnLast(nextColumn);
                     // This is a good point to call t.setSnippet(),
                     // but it bulks up the AST too much for production code.
                 }
             }

             GroovySourceAST child = (GroovySourceAST)t.getFirstChild();
             if (child != null) {
                 traverse(child,l,itr);
             }

             t = (GroovySourceAST)t.getNextSibling();
         }
    }
}