org.eclipse.linuxtools.lttng2.ui/src/org/eclipse/linuxtools/internal/lttng2/ui/views/control/handlers/BaseNodeHandler.java

   1 /**********************************************************************
   2  * Copyright (c) 2012 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Bernd Hufmann - Initial API and implementation
  11  **********************************************************************/
  12 package org.eclipse.linuxtools.internal.lttng2.ui.views.control.handlers;
  13
  14 import org.eclipse.jface.viewers.ISelection;
  15 import org.eclipse.jface.viewers.StructuredSelection;
  16 import org.eclipse.linuxtools.internal.lttng2.ui.views.control.ControlView;
  17 import org.eclipse.linuxtools.internal.lttng2.ui.views.control.model.impl.TargetNodeComponent;
  18 import org.eclipse.ui.IWorkbenchPage;
  19
  20 /**
  21  * <p>
  22  * Command handler implementation to delete a target host.
  23  * </p>
  24  *
  25  * @author Bernd Hufmann
  26  */
  27 abstract public class BaseNodeHandler extends BaseControlViewHandler {
  28
  29     // ------------------------------------------------------------------------
  30     // Attributes
  31     // ------------------------------------------------------------------------
  32     /**
  33      * The target node component the command is to be executed on.
  34      */
  35     protected TargetNodeComponent fTargetNode = null;
  36
  37     // ------------------------------------------------------------------------
  38     // Operations
  39     // ------------------------------------------------------------------------
  40     /*
  41      * (non-Javadoc)
  42      * @see org.eclipse.core.commands.AbstractHandler#isEnabled()
  43      */
  44     @Override
  45     public boolean isEnabled() {
  46
  47         // Get workbench page for the Control View
  48         IWorkbenchPage page = getWorkbenchPage();
  49         if (page == null) {
  50             return false;
  51         }
  52
  53         TargetNodeComponent node = null;
  54         // Check if the node component is selected
  55         ISelection selection = page.getSelection(ControlView.ID);
  56         if (selection instanceof StructuredSelection) {
  57             Object element = ((StructuredSelection) selection).getFirstElement();
  58             node = (element instanceof TargetNodeComponent) ? (TargetNodeComponent) element : null;
  59         }
  60         boolean isEnabled = node != null;
  61         fLock.lock();
  62         try {
  63             if (isEnabled) {
  64                 fTargetNode = node;
  65             }
  66         } finally {
  67             fLock.unlock();
  68         }
  69         return isEnabled;
  70     }
  71
  72
  73 }