/*
 * 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 util;

/**
 * HTML filter utility.
 *
 * @author Craig R. McClanahan
 * @author Tim Tye
 * @version $Revision: 466595 $ $Date: 2006-10-21 18:24:41 -0400 (Sat, 21 Oct 2006) $
 */

public final class HTMLFilter {


    /**
     * Filter the specified message string for characters that are sensitive
     * in HTML.  This avoids potential attacks caused by including JavaScript
     * codes in the request URL that is often reported in error messages.
     *
     * @param message The message string to be filtered
     */
    public static String filter(String message) {

        if (message == null)
            return (null);

        char content[] = new char[message.length()];
        message.getChars(0, message.length(), content, 0);
        StringBuffer result = new StringBuffer(content.length + 50);
        for (int i = 0; i < content.length; i++) {
            switch (content[i]) {
            case '<':
                result.append("&lt;");
                break;
            case '>':
                result.append("&gt;");
                break;
            case '&':
                result.append("&amp;");
                break;
            case '"':
                result.append("&quot;");
                break;
            default:
                result.append(content[i]);
            }
        }
        return (result.toString());

    }


}

