Put quotes around the given String if necessary in Java

//from   w ww  .  java 2 s.co m
public class Main {
  private static final String SINGLE_QUOTE = "\'";
  private static final String DOUBLE_QUOTE = "\"";

  public static void main(String[] argv) {
    System.out.println(quoteArgument("this is a test from java2s.com"));
  }

  /**
   * Put quotes around the given String if necessary.
   * 
   * If the argument doesn't include spaces or quotes, return it as is. If it
   * contains double quotes, use single quotes - else surround the argument by
   * double quotes.
   * 
   * 
   * @param argument
   *            the argument to be quoted
   * @return the quoted argument
   * @throws IllegalArgumentException
   *             If argument contains both types of quotes
   */
  public static String quoteArgument(final String argument) {

    String cleanedArgument = argument.trim();

    while (cleanedArgument.startsWith(SINGLE_QUOTE)
        || cleanedArgument.startsWith(DOUBLE_QUOTE)) {
      cleanedArgument = cleanedArgument.substring(1);
    }
    while (cleanedArgument.endsWith(SINGLE_QUOTE)
        || cleanedArgument.endsWith(DOUBLE_QUOTE)) {
      cleanedArgument = cleanedArgument.substring(0,
          cleanedArgument.length() - 1);
    }

    final StringBuffer buf = new StringBuffer();
    if (cleanedArgument.indexOf(DOUBLE_QUOTE) > -1) {
      if (cleanedArgument.indexOf(SINGLE_QUOTE) > -1) {
        throw new IllegalArgumentException(
            "Can't handle single and double quotes in same argument");
      } else {
        return buf.append(SINGLE_QUOTE).append(cleanedArgument)
            .append(SINGLE_QUOTE).toString();
      }
    } else if (cleanedArgument.indexOf(SINGLE_QUOTE) > -1
        || cleanedArgument.indexOf(" ") > -1) {
      return buf.append(DOUBLE_QUOTE).append(cleanedArgument)
          .append(DOUBLE_QUOTE).toString();
    } else {
      return cleanedArgument;
    }
  }
}

/*
 * 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.
 * 
 * @author <a href="mailto:siegfried.goeschl@it20one.at">Siegfried Goeschl</a>
 */