CommentFormatter.java

package org.springframework.roo.classpath.details.comments;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author Mike De Haan
 */
public class CommentFormatter {

  private static Pattern commentFormattingRegex = Pattern.compile("[\\s]*(.+)\\r?\\n?");

  /**
   * Format a given comment string with the indent level specified.
   * 
   * @param comment
   * @param indentLevel
   * @return
   */
  public String format(String comment, int indentLevel) {

    // Return if there's nothing to do
    if (comment == null) {
      return null;
    }

    final StringBuilder indentString = new StringBuilder();
    for (int i = 0; i < indentLevel; i++) {
      indentString.append("    ");
    }

    // Comment ends with newline
    boolean endsWithNewline = (comment.endsWith("\r\n") || comment.endsWith("\n"));

    List<String> matchList = new ArrayList<String>();
    Matcher regexMatcher = commentFormattingRegex.matcher(comment);
    while (regexMatcher.find()) {
      matchList.add(regexMatcher.group());
    }

    StringBuilder builder = new StringBuilder();

    for (int i = 0; i < matchList.size(); i++) {

      // We need to handle the last newline
      if (i == matchList.size() - 1) {
        builder.append(indentString.toString() + " " + matchList.get(i).trim()
            + (endsWithNewline ? "\n" : ""));
      } else if (i == 0) {
        builder.append(indentString.toString() + matchList.get(i).trim() + "\n");
      } else {
        builder.append(indentString.toString() + " " + matchList.get(i).trim() + "\n");
      }
    }

    return builder.toString();
  }

  /**
   * Formats a plain string (including newlines) and formats it as Javadoc.
   * 
   * @param input Plain string (including newlines) to be formatted as Javadoc
   * @return Formatted Javadoc
   */
  public String formatStringAsJavadoc(String input) {

    if (input == null) {
      return null;
    }

    final StringBuilder finalComment = new StringBuilder("/**\n");
    Matcher regexMatcher = commentFormattingRegex.matcher(input);
    while (regexMatcher.find()) {
      finalComment.append("* ");
      finalComment.append(regexMatcher.group());
    }
    finalComment.append("\n*/\n");

    return finalComment.toString();
  }
}