plugins/org.eclipse.emf.cdo.explorer.ui/src/org/eclipse/emf/cdo/explorer/ui/handlers/AbstractObjectHandler.java

/*
 * Copyright (c) 2015 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Eike Stepper - initial API and implementation
 */
package org.eclipse.emf.cdo.explorer.ui.handlers;

import org.eclipse.emf.cdo.CDOElement;
import org.eclipse.emf.cdo.explorer.CDOExplorerUtil;
import org.eclipse.emf.cdo.explorer.checkouts.CDOCheckout;
import org.eclipse.emf.cdo.transaction.CDOTransaction;

import org.eclipse.net4j.util.ui.UIUtil;
import org.eclipse.net4j.util.ui.handlers.AbstractBaseHandler;

import org.eclipse.emf.ecore.EObject;

import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.StructuredSelection;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Eike Stepper
 */
public abstract class AbstractObjectHandler extends AbstractBaseHandler<EObject>
{
  private CDOCheckout checkout;

  public AbstractObjectHandler(Boolean multi)
  {
    super(EObject.class, multi);
  }

  public final CDOCheckout getCheckout()
  {
    return checkout;
  }

  @Override
  protected boolean updateSelection(ISelection selection)
  {
    checkout = null;
    if (super.updateSelection(selection))
    {
      for (EObject eObject : elements)
      {
        CDOCheckout objectCheckout = CDOExplorerUtil.getCheckout(eObject);
        if (objectCheckout == null || !objectCheckout.isOpen())
        {
          checkout = null;
          return false;
        }

        if (checkout == null)
        {
          checkout = objectCheckout;
        }
        else if (checkout != objectCheckout)
        {
          checkout = null;
          return false;
        }
      }

      return true;
    }

    return false;
  }

  @Override
  protected List<EObject> collectElements(ISelection selection)
  {
    List<Object> elements = UIUtil.getElements(selection);
    if (elements != null)
    {
      List<Object> result = new ArrayList<Object>();

      for (Object element : elements)
      {
        if (element instanceof CDOElement)
        {
          CDOElement checkoutElement = (CDOElement)element;
          for (Object child : checkoutElement.getChildren())
          {
            result.add(child);
          }
        }
        else
        {
          result.add(element);
        }
      }

      selection = new StructuredSelection(result);
    }

    return super.collectElements(selection);
  }

  @Override
  protected void doExecute(ExecutionEvent event, IProgressMonitor monitor) throws Exception
  {
    CDOTransaction transaction = checkout.openTransaction();

    try
    {
      List<EObject> transactionalElements = new ArrayList<EObject>();
      for (EObject element : elements)
      {
        if (monitor.isCanceled())
        {
          throw new OperationCanceledException();
        }

        EObject transactionalElement = transaction.getObject(element);
        transactionalElements.add(transactionalElement);
      }

      if (doExecute(event, transactionalElements, monitor))
      {
        transaction.commit(monitor);
      }
    }
    finally
    {
      transaction.close();
    }
  }

  protected abstract boolean doExecute(ExecutionEvent event, List<EObject> transactionalElements,
      IProgressMonitor monitor);
}