htmlfilter.java

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/*
 * Copyright 2003-2005 the original author or authors.
 * Licensed 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 com.jdon.jivejdon.model.message.output.html;

import com.jdon.jivejdon.model.ForumMessage;
import com.jdon.jivejdon.model.message.MessageRendering;

/**
 * A ForumMessageFilter that converts newline characters into HTML <br> tags.
 * This filter should only be run after any HTML stripping filters.
 */
public class HTMLFilter extends MessageRendering {

    private static final char[] QUOTE_ENCODE = """.toCharArray();
    private static final char[] AMP_ENCODE = "&".toCharArray();
    private static final char[] LT_ENCODE = "<".toCharArray();
    private static final char[] GT_ENCODE = ">".toCharArray();

    /**
     * Clones a new filter that will have the same properties and that
     * will wrap around the specified message.
     *
     * @param message the ForumMessage to wrap the new filter around.
     */
    public MessageRendering clone(ForumMessage message){
        HTMLFilter filter = new HTMLFilter();
        filter.message = message;
        return filter;
    }

   

    /**
     * <b>Overloaded</b> to return the subject of the message with HTML tags
     * escaped.
     */
    public String applyFilteredSubject() {
        return escapeHTMLTags(message.getFilteredSubject());
    }

    /**
     * <b>Overloaded</b> to return the body of the message with HTML tags
     * escaped.
     */
    public String applyFilteredBody() {
        return escapeHTMLTags(message.getFilteredBody());
    }
    
    /**
     * This method takes a string which may contain HTML tags (ie, &lt;b&gt;,
     * &lt;table&gt;, etc) and converts the '&lt'' and '&gt;' characters to
     * their HTML escape sequences.
     *
     * @param in the text to be converted.
     * @return the input string with the characters '&lt;' and '&gt;' replaced
     *  with their HTML escape sequences.
     */
    public static final String escapeHTMLTags(String in) {
        if (in == null) {
            return null;
        }
        char ch;
        int i=0;
        int last=0;
        char[] input = in.toCharArray();
        int len = input.length;
        StringBuffer out = new StringBuffer((int)(len*1.3));
        for (; i < len; i++) {
            ch = input[i];
            if (ch > '>') {
                continue;
            } else if (ch == '<') {
                if (i > last) {
                    out.append(input, last, i - last);
                }
                last = i + 1;
                out.append(LT_ENCODE);
            } else if (ch == '>') {
                if (i > last) {
                    out.append(input, last, i - last);
                }
                last = i + 1;
                out.append(GT_ENCODE);
            }
        }
        if (last == 0) {
            return in;
        }
        if (i > last) {
            out.append(input, last, i - last);
        }
        return out.toString();
    }
}