Question

New to java… Trying to get a sample app to run. I’m including the section of code that appears to be relevant to the issue. I can post the entire test app if needed. I

I’m trying to implement the errorhandler to handle the css warnings that are generated when the app is parsing targeted websites via the htmlunit lib/test that the app runs.

I’m not sure exactly how the MycssErrorHandler class should be implemented in order to invoke the ErrorHandler. I’m also not exactly sure how to instantiate the object in the main body of the code/test class.

Thoughts/Comments/Code chunks would be helpful..

Thanks!

I’m getting the following error when I compile:

[root@toshiba parseapp2]# javac -Xlint -classpath '/opt/htmlunit/lib/*:/parseapp2/' sjsu_classes.java

warning: [path] bad path element "/opt/htmlunit/lib/xml-apis.jar": no such file or directory
warning: [path] bad path element "/opt/htmlunit/lib/xercesImpl.jar": no such file or directory
warning: [path] bad path element "/opt/htmlunit/lib/serializer.jar": no such file or directory
sjsu_classes.java:92: sjsu_classes.MycssErrorHandler is abstract; cannot be instantiated
        ErrorHandler ierr = new MycssErrorHandler(); 
                        ^
1 error
3 warnings

====================================

The test code chunk is:

import org.w3c.css.sac.ErrorHandler;
    import com.gargoylesoftware.htmlunit.DefaultCssErrorHandler;
import org.xml.sax.SAXParseException;

public class sjsu_classes {

    //==handle the warnings thrown from the js functions..
    public static class MyIncorrectnessListener implements IncorrectnessListener
    {
      @Override
      public void notify(String arg0, Object arg1)
      {
        //System.err.println("Argument : " + arg0.toString() + ", Object : ");
      }
    }     

    //==handle the warnings thrown from the css functions..
//  public static class MycssErrorHandler implements DefaultCssErrorHandler
//  public static class MycssErrorHandler implements ErrorHandler
//  public class MycssErrorHandler implements ErrorHandler
    public abstract class MycssErrorHandler implements ErrorHandler
//  protected class MycssErrorHandler implements ErrorHandler
    {
      //@Override
      public void notify(String arg0, Object arg1)
      {
        //System.err.println("Argument : " + arg0.toString() + ", Object : ");
      }
      //@Override
        public void fatalError(SAXParseException ex)
        {
            //fatals.add(ex);
        }
    } 

    //public static void main(String[] args) throws Exception {
    public void main(String[] args) throws Exception {

        // Create and initialize WebClient object
//     WebClient webClient = new WebClient(BrowserVersion.EXPLORER_7);
       WebClient webClient = new WebClient(BrowserVersion.FIREFOX_3);
           //WebClient webClient = new WebClient();

        IncorrectnessListener ilisten = new MyIncorrectnessListener(); 
        ErrorHandler ierr = new MycssErrorHandler(); 
        webClient.setIncorrectnessListener(ilisten); 
        webClient.setCssErrorHandler(ierr); 

Answer 1

Your MycssErrorHandler class is abstract, meaning that you can’t use it directly.

An abstract class cannot be instantiated; it can only be inherited from.

You need to remove the abstract keyword from the class definition.

Once you remove the abstract keyword, you will also need to make your class implement all three method in the ErrorHandler interface. (error, fatalError, and warning)