package com.melloware.jukes.gui.view.editor;
   
   import java.awt.Component;
   import java.beans.PropertyChangeEvent;
   import java.beans.PropertyChangeListener;
   import java.util.HashMap;
   import java.util.Iterator;
   import java.util.LinkedList;
   import java.util.List;
  import java.util.Map;
  
  import javax.swing.JComponent;
  import javax.swing.JPanel;
  import javax.swing.JScrollPane;
  import javax.swing.SwingUtilities;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import com.jgoodies.uifextras.util.UIFactory;
  import com.melloware.jukes.gui.tool.MainModule;
  import com.melloware.jukes.gui.view.component.ComplexInternalFrame;
  
  /**
   * A container that wraps <code>Editor</code> instances with a
   * <code>JScrollPane</code>, which in turn is wrapped by
   * a <code>SimpleInternalFrame</code>.<p>
   *
   * It keeps track of a collection of editors to be able to update
   * the UIs of invisible editors when the look&amp;feel changes.
   * <code>SwingUtilities#updateComponentTreeUI</code> updates
   * only editors that are in the component tree. Since we have only
   * the active editor in the component tree, we must update other
   * editors <em>by hand</em>.
   * An alternative implementation is to use a <code>CardPanel</code>
   * that has all editors in the component tree, but displays one of them
   * and hides all others.
   * <p>
   * Copyright (c) 1999-2007 Melloware, Inc. <http://www.melloware.com>
   * @author Emil A. Lefkof III <info@melloware.com>
   * @version 4.0
   *
   * @see MainModule
   * @see Editor
   * @see javax.swing.SwingUtilities#updateComponentTreeUI(java.awt.Component)
   */
  @SuppressWarnings("unchecked")
  public final class EditorPanel
      extends ComplexInternalFrame { 
  
      private static final Log LOG = LogFactory.getLog(EditorPanel.class);
  
      private JScrollPane scrollPane;
  
      /**
       * Holds a list of all editors to update the UI of invisible editors
       * in case the look&amp;feel changes. Contains some editors that
       * are not registered with the editor registry, for example the
       * WelcomePanel that has no associated domain class.
       *
       * @see #updateUI()
       */
      private final List editors;
  
      /**
       * Maps domain classes to <code>Editor</code> instances.
       *
       * @see #addEditor(Editor)
       */
      private final Map editorRegistry;
  
      /**
       * Constructs a <code>EditorPanel</code>.
       *
       * @param mainModule   used to observe selection changes
       */
      public EditorPanel(MainModule mainModule) {
          super("Editor");
          editorRegistry = new HashMap();
          editors = new LinkedList();
          setContent(buildContent());
  
          mainModule.addPropertyChangeListener(MainModule.PROPERTYNAME_SELECTION, new SelectionChangeHandler());
      }
  
      /**
       * Gets the editors.
       * <p>
       * @return Returns the editors.
       */
      public List getEditors() {
          return this.editors;
      }
  
      /**
       * Shows the specified <code>Editor</code>: sets the icon,
       * title, tool bar, and finally switches the viewport's view.
       *
       * @param newEditor   the editor to be set
      */
     public void setActiveEditor(Editor newEditor) {
         setFrameIcon(newEditor.getIcon());
         setTitle(newEditor.getTitle());
         setToolBar(newEditor.getToolBar());
         setHeaderToolBar(newEditor.getHeaderToolBar());
         scrollPane.setViewportView((Component)newEditor);
     }
 
     /**
      * Adds a <code>Editor</code> to this <code>EditorPanel</code>.
      *
      * @param editor   the editor to add
      */
     public void addEditor(Editor editor) {
         Class domainClass = editor.getDomainClass();
         if (domainClass != null) {
             registerEditor(domainClass, editor);
         }
 
         editors.add(editor);
     }
     
     /**
      * Clears all editors out.
      */
     public void clearEditors() {
     	editors.clear();
     }
 
     /**
      * The look&amp;feel has changed. Updates the UI.
      * In addition to the superclass behavior, this method
      * updates the component trees for the invisible editors.
      */
     public void updateUI() {
         super.updateUI();
         if (editors == null) {
             return;
         }
 
         for (Iterator i = editors.iterator(); i.hasNext();) {
             JComponent viewer = (JComponent)i.next();
             // The Swing Suite provides class MySwingUtilities
             // that fixes bugs with l&f switching at runtime.
             SwingUtilities.updateComponentTreeUI(viewer);
         }
     }
 
     /**
      * Returns the current <code>Editor</code>.
      *
      * @return the current <code>Editor</code>.
      */
     private Editor getActiveEditor() {
         return (Editor)scrollPane.getViewport().getView();
     }
 
     /**
      * Builds the content, which is a panel wrapped by a stripped
      * <code>JScrollPane</code>. The panel will be replaced later
      * by the different viewers, where we access the viewer via
      * the scrollpane's viewport view.
      */
     private JComponent buildContent() {
         return scrollPane = UIFactory.createStrippedScrollPane(new JPanel());
     }
 
     /**
      * Returns the <code>Editor</code> that has been registered
      * for the given domain object class, <code>null</code> if none.
      *
      * @param domainClass   the class associated with the editor to lookup
      * @return the editor associated with the given domain class
      */
     private Editor lookupEditor(Class domainClass) {
         return (Editor)editorRegistry.get(domainClass);
     }
 
     /**
      * Registers a <code>Editor</code> for a domain class.
      *
      * @param domainClass   the key used to lookup the editor later
      * @param editor        the value stored under the given domain class
      */
     private void registerEditor(Class domainClass, Editor editor) {
         Object oldValue = editorRegistry.put(domainClass, editor);
         if (oldValue != null) {
             LOG.debug("Duplicate editor registered for " + domainClass);
         }
     }
 
     /**
      * Deactivates the current editor, looks up appropriate viewer for
      * the new selection, sets the model, activates it and makes it visible.
      *
      * @param selection   the new domain selection
      */
     private void updateActiveEditor(Object selection) {
         if (selection == null) {
             return;
         }
 
         getActiveEditor().deactivate();
         Editor editor = lookupEditor(selection.getClass());
         if (editor != null) {
             editor.setModel(selection);
             editor.activate();
             setActiveEditor(editor);
         }
     }
 
     // Listens to changes in the main module's selection and updates the editor.
     private class SelectionChangeHandler
         implements PropertyChangeListener {
 
         /**
          * The main module's selection has changed. Look up the editor
          * registered for the selection's domain class, deactivate the active
          * editor, activate the new editor and set is as active editor.
          *
          * @param evt   describes the property change
          */
         public void propertyChange(PropertyChangeEvent evt) {
             if (evt.getNewValue() == null) {
                 // gets the first editor in the list if no event found
                 setActiveEditor((Editor)getEditors().get(0));
             } else {
                 updateActiveEditor(evt.getNewValue());
             }
         }
     }
 
 }