home | career | drupal | java | mac | mysql | perl | scala | uml | unix

Groovy example source code file (SourceBuffer.java)

This example Groovy source code file (SourceBuffer.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

arraylist, linecolumn, linecolumn, list, sourcebuffer, sourcebuffer, string, string, stringbuffer, stringbuffer, util

The Groovy SourceBuffer.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;

import java.util.List;
import java.util.ArrayList;

/**
 * A simple buffer that provides line/col access to chunks of source code
 * held within itself.
 *
 * @author <a href="mailto:groovy@ross-rayner.com">Jeremy Rayner
 * @version $Revision: 7922 $
 */
public class SourceBuffer {
    private final List lines;
    private StringBuffer current;

    public SourceBuffer() {
        lines = new ArrayList();
        //lines.add(new StringBuffer()); // dummy row for position [0] in the List

        current = new StringBuffer();
        lines.add(current);
    }

    /**
     * Obtains a snippet of the source code within the bounds specified
     * @param start (inclusive line/ inclusive column)
     * @param end (inclusive line / exclusive column)
     * @return specified snippet of source code as a String, or null if no source available
     */
    public String getSnippet(LineColumn start, LineColumn end) {
        // preconditions
        if (start == null || end == null) { return null; } // no text to return
        if (start.equals(end)) { return null; } // no text to return
        if (lines.size() == 1 && current.length() == 0) { return null; } // buffer hasn't been filled yet

        // working variables
        int startLine = start.getLine();
        int startColumn = start.getColumn();
        int endLine = end.getLine();
        int endColumn = end.getColumn();

        // reset any out of bounds requests
        if (startLine < 1) { startLine = 1;}
        if (endLine < 1) { endLine = 1;}
        if (startColumn < 1) { startColumn = 1;}
        if (endColumn < 1) { endColumn = 1;}
        if (startLine > lines.size()) { startLine = lines.size(); }
        if (endLine > lines.size()) { endLine = lines.size(); }

        // obtain the snippet from the buffer within specified bounds
        StringBuffer snippet = new StringBuffer();
        for (int i = startLine - 1; i < endLine;i++) {
            String line = ((StringBuffer)lines.get(i)).toString();
            if (startLine == endLine) {
                // reset any out of bounds requests (again)
                if (startColumn > line.length()) { startColumn = line.length();}
                if (startColumn < 1) { startColumn = 1;}
                if (endColumn > line.length()) { endColumn = line.length() + 1;}
                if (endColumn < 1) { endColumn = 1;}

                line = line.substring(startColumn - 1, endColumn - 1);
            } else {
                if (i == startLine - 1) {
                    if (startColumn - 1 < line.length()) {
                        line = line.substring(startColumn - 1);
                    }
                }
                if (i == endLine - 1) {
                    if (endColumn - 1 < line.length()) {
                        line = line.substring(0,endColumn - 1);
                    }
                }
            }
            snippet.append(line);
        }
        return snippet.toString();
    }

    /**
     * Writes the specified character into the buffer
     * @param c
     */
    public void write(int c) {
        if (c != -1) {
            current.append((char)c);
        }
        if (c == '\n') {
            current = new StringBuffer();
            lines.add(current);
        }
    }
}

Other Groovy examples (source code examples)

Here is a short list of links related to this Groovy SourceBuffer.java source code file:

new blog posts

 

Copyright 1998-2013 Alvin Alexander, alvinalexander.com
All Rights Reserved.