source: main/trunk/greenstone3/src/java/org/greenstone/admin/guiext/ExtensionInformation.java@ 21919

package org.greenstone.admin.guiext;

import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import java.net.URLClassLoader;
import java.net.URL;

import java.lang.reflect.Method;
import java.lang.reflect.Constructor;

import java.io.File;

import java.awt.BorderLayout;

import javax.swing.JTextArea;
import javax.swing.JPanel;

import org.greenstone.admin.GAI;

public class ExtensionInformation
{
    protected String _name = null;
    protected String _group = null;
    protected String _fileStem = null;
    protected String _description = null;
    protected String _baseExt = null;
    protected String _baseURL = null;
    protected SequenceList _sequenceList= null;
    protected boolean _guiExtLoaded = false;

    protected static JPanel _extPane = new JPanel();

    public ExtensionInformation(Element extensionElement, String baseURL){
    if(extensionElement != null){
        _name = ExtXMLHelper.getValueFromSingleElement(extensionElement, ExtXMLHelper.NAME, true);
        _group = ExtXMLHelper.getValueFromSingleElement(extensionElement, ExtXMLHelper.GROUP, true);
        _fileStem = ExtXMLHelper.getValueFromSingleElement(extensionElement, ExtXMLHelper.FILE_STEM, true);
        _description = ExtXMLHelper.getValueFromSingleElement(extensionElement, ExtXMLHelper.DESCRIPTION, true);
        _baseExt = ExtXMLHelper.getValueFromSingleElement(extensionElement, ExtXMLHelper.BASE_EXT, true);
        _baseURL = baseURL;
        _sequenceList = new SequenceList(ExtXMLHelper.getSingleChildElement(extensionElement, ExtXMLHelper.SEQUENCE_LIST, true), this);
    }
    else{
        System.err.println("<" + ExtXMLHelper.EXTENSION + "> element is null");
    }
    }

    public String getBaseURL()
    {
    return _baseURL;
    }

    public String getName()
    {
    return _name;
    }

    public String getGroup()
    {
    return _group;
    }
    
    public String getFileStem()
    {
    return _fileStem;
    }

    public String getDescription()
    {
    return _description;
    }
 
    public String getBaseClassName()
    {
    return _baseExt;
    }

    public SequenceList getSequenceList()
    {
    return _sequenceList;
    }

    public Object getExtObject()
    {
    loadGuiExtFile();
    Class extClass = null;
    try{
        extClass = Class.forName(_baseExt);
    }
    catch(Exception ex){
        System.err.println("Could not create the extension class used for callback methods, either the class name is incorrect or the class does not exist inside the guiext.jar file");
    }
    Constructor classConstructor = null;
    Object classObj = null;
    
    try{
        classConstructor = extClass.getConstructor(new Class[0]);
        classObj = classConstructor.newInstance(new Object[0]);
    }
    catch(Exception ex){
        ex.printStackTrace();
        System.err.println("Could not create the extension class used for callback methods, either the class name is incorrect or the class does not exist inside the guiext.jar file");
        return null;
    }
    
    return classObj;
    }

    public void loadExternalJar(String filename){
    //Load the dynamic jar loader
    URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
    Class sysclass = URLClassLoader.class;
    final Class[] parameters = new Class[]{URL.class};
    Method method = null;
    try{
        method = sysclass.getDeclaredMethod("addURL", parameters);
    }
    catch(Exception ex){
        ex.printStackTrace();
    }
    method.setAccessible(true);

    File externalFile = new File(filename);
    if(!externalFile.exists()){
        System.err.println("Cannot load the external jar file at " + filename + " as it does not exist");
        return;
    }

    try {
        URL u = new URL(externalFile.toURI().toURL().toString());
        method.invoke(sysloader, new Object[]{u});
    } catch (Throwable t) {
        t.printStackTrace();
    }

    _guiExtLoaded = true;
    }

    public void loadGuiExtFile()
    {
    if(!_guiExtLoaded){
        loadExternalJar(getExtensionDirectory() + System.getProperty("file.separator") + "guiext.jar");     
    }
    }    

    public boolean isGuiExtLoaded()
    {
    return _guiExtLoaded;
    }

    public void changeExtPane(JPanel extPane)
    {
    _extPane.removeAll();
    _extPane.add(extPane, BorderLayout.CENTER);
    _extPane.revalidate();
    _extPane.repaint();
    }

    public static void setExtPane(JPanel extPane)
    {   
    _extPane = extPane;
    }

    public JPanel getExtPane()
    {
    return _extPane;
    }

    public String getExtensionDirectory()
    {
    return GAI.getGSDL3ExtensionHome() + System.getProperty("file.separator") + _fileStem;
    }
}