ResponseUtils.java :  » GWT » ftr-gwt-library » eu » future » earth » gwt » tags » Java Open Source

/*
 * $Id: ResponseUtils.java 471754 2006-11-06 14:55:09Z husted $
 *
 * 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 eu.future.earth.gwt.tags;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

/**
 * General purpose utility methods related to generating a servlet response in the Struts controller framework.
 * 
 * @version $Rev: 471754 $ $Date: 2005-08-21 14:46:28 -0400 (Sun, 21 Aug 2005) $
 */
public class ResponseUtils {

  // --------------------------------------------------------- Public Methods

  /**
   * Filter the specified string for characters that are senstive to HTML interpreters, returning the string with these characters replaced by the corresponding character entities.
   * 
   * @param value
   *            The string to be filtered and returned
   */
  public static String filter(String value) {
    if ((value == null) || (value.length() == 0)) {
      return value;
    }

    StringBuffer result = null;
    String filtered = null;

    for (int i = 0; i < value.length(); i++) {
      filtered = null;

      switch (value.charAt(i)) {
      case '<':
        filtered = "&lt;";

        break;

      case '>':
        filtered = "&gt;";

        break;

      case '&':
        filtered = "&amp;";

        break;

      case '"':
        filtered = "&quot;";

        break;

      case '\'':
        filtered = "&#39;";

        break;
      }

      if (result == null) {
        if (filtered != null) {
          result = new StringBuffer(value.length() + 50);

          if (i > 0) {
            result.append(value.substring(0, i));
          }

          result.append(filtered);
        }
      } else {
        if (filtered == null) {
          result.append(value.charAt(i));
        } else {
          result.append(filtered);
        }
      }
    }

    return (result == null) ? value : result.toString();
  }

  /**
   * URLencodes a string assuming the character encoding is UTF-8.
   * 
   * @param url
   * @return String The encoded url in UTF-8
   */
  public static String encodeURL(String url) {
    return encodeURL(url, "UTF-8");
  }

  @SuppressWarnings("deprecation")
  public static String encodeURL(String url, String enc) {
    try {
      if ((enc == null) || (enc.length() == 0)) {
        enc = "UTF-8";
      }
      return URLEncoder.encode(url, enc);
    } catch (UnsupportedEncodingException e) {
      // NOPMD;
    }

    return URLEncoder.encode(url);
  }
}