1 files changed, 99 insertions, 0 deletions
diff --git a/src/main/java/org/cristalise/gui/graph/controller/DeletionController.java b/src/main/java/org/cristalise/gui/graph/controller/DeletionController.java
new file mode 100644
index 0000000..b97ec11
--- /dev/null
+++ b/src/main/java/org/cristalise/gui/graph/controller/DeletionController.java
@@ -0,0 +1,99 @@
+package org.cristalise.gui.graph.controller;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.KeyAdapter;
+import java.awt.event.KeyEvent;
+import java.util.Observable;
+import java.util.Observer;
+
+import javax.swing.JButton;
+
+import org.cristalise.gui.graph.event.SelectionChangedEvent;
+import org.cristalise.gui.graph.view.GraphPanel;
+import org.cristalise.kernel.graph.model.DirectedEdge;
+import org.cristalise.kernel.graph.model.GraphModelManager;
+import org.cristalise.kernel.graph.model.Vertex;
+
+
+
+// The deletion controller is responsible for deleting the present
+// selection within the graph.
+//
+// The controller listens to:
+//     * The graph model to determine if there is a selection
+//     * The delete button
+//     * The graph panel for the typing of the delete key
+//
+// The controller modifies:
+//     * The graph model to delete the current selection
+//     * The delete button to enable it only when there is a selection
+public class DeletionController extends KeyAdapter implements Observer, ActionListener
+{
+    private GraphModelManager mGraphModelManager   = null;
+    private GraphPanel		  mGraphPanel          = null;
+    private JButton           mDeleteButton        = null;
+
+
+    public void setGraphModelManager(GraphModelManager graphModelManager)
+    {
+        mGraphModelManager = graphModelManager;
+        mGraphModelManager.addObserver(this);
+    }
+    
+    public void setGraphPanel(GraphPanel graphPanel)
+    {
+        mGraphPanel = graphPanel;
+    }
+
+
+    public void setDeleteButton(JButton deleteButton)
+    {
+        mDeleteButton = deleteButton;
+        mDeleteButton.addActionListener(this);
+    }
+
+
+    // Invoked by the graph model
+    @Override
+	public void update(Observable o, Object arg)
+    {
+        SelectionChangedEvent event            = null;
+        DirectedEdge          selectedEdge     = null;
+        Vertex[]              selectedVertices = null;
+
+
+        // If the selected edge has changed
+        if(arg instanceof SelectionChangedEvent && mDeleteButton != null  && mGraphModelManager.isEditable())
+        {
+            // Enable the button if a single edge or single vertex is selected
+            event            = (SelectionChangedEvent)arg;
+
+            selectedEdge     = event.mSelection.mEdge;
+            selectedVertices = event.mSelection.mVertices;
+            mDeleteButton.setEnabled(selectedEdge != null || selectedVertices != null);
+        }
+    }
+
+
+    // Invoked by the graph panel
+    @Override
+	public void keyPressed(KeyEvent e)
+    {
+        if(e.getKeyCode() == KeyEvent.VK_DELETE && mGraphModelManager.isEditable())
+        {
+        	mGraphPanel.deleteSelection();
+        }
+    }
+
+
+    // Invoked by the delete button
+    @Override
+	public void actionPerformed(ActionEvent ae)
+    {
+        if(mGraphModelManager != null && mGraphModelManager.isEditable())
+        {
+        	mGraphPanel.deleteSelection();
+        }
+    }
+}