Question

I have (still) problems with HTMLEditorKit and HTMLDocument in Java. I can only set the inner HTML of an element, but I cannot get it. Is there some way, how to get a uderlying HTML code of an element?

My problem is, that the HTML support is quite poor and bad written. The API does not allow basic and expected functions. I need change the colspan or rowspan attribute of <td>. The Java developers have closed the straightforward way: the attribute set of element is immutable. The workaround could be to take the code of element (e.g. <td colspan="2">Hi <u>world</u></td>) and replace it with new content (e.g. <td colspan="3">Hi <u>world</u></td>). This way seems to be closed too. (Bonus question: What’s the HTMLEditorKit good for?)

Answer 1

Thanks for hint, Stanislav. That’s my solution:

/**
 * The method gets inner HTML of given element. If the element is named <code>p-implied</code>
 * or <code>content</code>, it returns null.
 * @param e element
 * @param d document containing given element
 * @return the inner HTML of a HTML tag or null, if e is not a valid HTML tag
 * @throws IOException
 * @throws BadLocationException
 */
public String getInnerHtmlOfTag(Element e, Document d) throws IOException, BadLocationException {
    if (e.getName().equals("p-implied") || e.getName().equals("content"))
        return null;

    CharArrayWriter caw = new CharArrayWriter();
    int i;
    final String startTag = "<" + e.getName();
    final String endTag = "</" + e.getName() + ">";
    final int startTagLength = startTag.length();
    final int endTagLength = endTag.length();

    write(caw, d, e.getStartOffset(), e.getEndOffset() - e.getStartOffset());
    //we have the element but wrapped as full standalone HTML code beginning with HTML start tag
    //thus we need unpack our element
    StringBuffer str = new StringBuffer(caw.toString());
    while (str.length() >= startTagLength) {
        if (str.charAt(0) != '<')
            str.deleteCharAt(0);
        else if (!str.substring(0, startTagLength).equals(startTag))
            str.delete(0, startTagLength);
        else
            break;
    }
    //we've found the beginning of the tag
    for (i = 0; i < str.length(); i++) { //skip it...
        if (str.charAt(i) == '>')
            break; //we've found end position of our start tag
    }
    str.delete(0, i + 1); //...and eat it
    //skip the content
    for (i = 0; i < str.length(); i++) {
        if (str.charAt(i) == '<' && i + endTagLength < str.length() && str.substring(i, i + endTagLength).equals(endTag))
            break; //we've found the end position of inner HTML of our tag
    }
    str.delete(i, str.length()); //now just remove all from i position to the end

    return str.toString().trim();
}

This method can be easilly modified to get outter HTML (so the code containing the entire tag).