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  * <b><u>BaseNodeHandler</u></b>
  22  * <p>
  23  * Command handler implementation to delete a target host.
  24  * </p>
  25  */
  26 abstract public class BaseNodeHandler extends BaseControlViewHandler {
  27
  28     // ------------------------------------------------------------------------
  29     // Attributes
  30     // ------------------------------------------------------------------------
  31     /**
  32      * The target node component the command is to be executed on.
  33      */
  34     protected TargetNodeComponent fTargetNode = null;
  35
  36     // ------------------------------------------------------------------------
  37     // Operations
  38     // ------------------------------------------------------------------------
  39     /*
  40      * (non-Javadoc)
  41      * @see org.eclipse.core.commands.AbstractHandler#isEnabled()
  42      */
  43     @Override
  44     public boolean isEnabled() {
  45
  46         // Get workbench page for the Control View
  47         IWorkbenchPage page = getWorkbenchPage();
  48         if (page == null) {
  49             return false;
  50         }
  51
  52         TargetNodeComponent node = null;
  53         // Check if the node component is selected
  54         ISelection selection = page.getSelection(ControlView.ID);
  55         if (selection instanceof StructuredSelection) {
  56             Object element = ((StructuredSelection) selection).getFirstElement();
  57             node = (element instanceof TargetNodeComponent) ? (TargetNodeComponent) element : null;
  58         }
  59         boolean isEnabled = node != null;
  60         fLock.lock();
  61         try {
  62             if (isEnabled) {
  63                 fTargetNode = node;
  64             }
  65         } finally {
  66             fLock.unlock();
  67         }
  68         return isEnabled;
  69     }
  70
  71
  72 }