SourceHighLighter.java :  » Workflow-Engines » bpmscript » org » bpmscript » web » Java Open Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.bpmscript.web;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang.StringEscapeUtils;

public class SourceHighLighter {
  
  private enum HighlightColour { RED, GREEN, BLUE };

  private HighlightColour highlightColor = HighlightColour.GREEN;

  private String format = "<a name=\"{0}\"><span style=\"background-color: {1}\">{2}</span></a>";

  private String lineSeparator = System.getProperty("line.separator");
  
  private int colourStrength = 220;
  
  /**
   * Goes through the stack trace getting elements relevant to this
   * source given the name. A range of colors is used to show which
   * level it's at, darker colors means it's higher up the stack.
   * 
   * @param name
   * @param source
   * @param stackTrace
   * @return
   */
  public String highlight(String name, String source, StackTraceElement[] stackTrace) {
    
    Map<Integer, Integer> map = new HashMap<Integer, Integer>();
    StringBuffer result = new StringBuffer();

    int counter = 0;
    for (StackTraceElement element : stackTrace) {
      if(name.equals(element.getFileName())) {
        map.put(element.getLineNumber(), counter++);
      }
    }
    
    BufferedReader reader = new BufferedReader(new StringReader(source));
    
    String line = null;
    int period = 245 / counter;

    try {
      int lineNumber = 0;
      while((line = reader.readLine()) != null) {
        Integer depth = map.get(lineNumber);
        result.append(lineNumber + " ");
        if(depth != null) {
          int level = period * depth + 10;
          String webColor = toWebColor(
              (highlightColor == HighlightColour.RED ? colourStrength : level),
              (highlightColor == HighlightColour.GREEN ? colourStrength : level),
              (highlightColor == HighlightColour.BLUE ? colourStrength : level)
              );
          result.append(MessageFormat.format(format, name + '-' + lineNumber, webColor, StringEscapeUtils.escapeHtml(line)));
          result.append(lineSeparator);
        } else {
          result.append(StringEscapeUtils.escapeHtml(line));
          result.append(lineSeparator);
        }
        lineNumber++;
      }
    } catch (IOException e) {
      // should never happen with a string reader!
      throw new RuntimeException(e);
    }
    return result.toString();
  }
  
  public String addLineNumbers(String source) {
    StringBuffer result = new StringBuffer();
    BufferedReader reader = new BufferedReader(new StringReader(source));
    int lineNumber = 0;
    String line = null;
    try {
      while((line = reader.readLine()) != null) {
        result.append(lineNumber++);
        result.append(" ");
        result.append(line);
        result.append(lineSeparator);
      }
    } catch (IOException e) {
      // should never happen with a string reader!
      throw new RuntimeException(e);
    }
    return result.toString();
  }
  
  public String toWebColor(int red, int green, int blue) {
    return '#' + toHex(red) + toHex(green) + toHex(blue);
  }
  
  public String toHex(int value) {
    String hex = Integer.toHexString(value);
    if(hex.length() == 1) {
      hex = '0' + hex;
    }
    return hex;
  }
}