org.eclipse.gmf.runtime.emf.type.core/src/org/eclipse/gmf/runtime/emf/type/core/requests/GetEditContextRequest.java

/******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation 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:
 *    IBM Corporation - initial API and implementation 
 ****************************************************************************/

package org.eclipse.gmf.runtime.emf.type.core.requests;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.gmf.runtime.emf.type.core.EditHelperContext;
import org.eclipse.gmf.runtime.emf.type.core.IClientContext;
import org.eclipse.gmf.runtime.emf.type.core.IElementType;

/**
 * Request to get the context for editing a model element.
 * <P>
 * The context is used to obtain the <code>IEditHelper</code> with which to
 * perform the editing.
 * 
 * @author ldamus
 */
public class GetEditContextRequest extends AbstractEditCommandRequest {

	/**
	 * The edit request.
	 */
	private final IEditCommandRequest editRequest;

	/**
	 * The edit helper context for this request.
	 */
	private final Object editHelperContext;

	/**
	 * The resulting edit context.
	 */
	private Object editContext;

	/**
	 * Constructs a new request.
	 * 
	 * @param editingDomain
	 *            the editing domain in which I am requesting to make model
	 * @param editRequest
	 *            the edit request whose context is being requested
	 */
	public GetEditContextRequest(TransactionalEditingDomain editingDomain,
			IEditCommandRequest editRequest, Object editHelperContext) {

		super(editingDomain);
		this.editRequest = editRequest;
		this.editHelperContext = editHelperContext;
		addParameters(editRequest.getParameters());
	}
    
    /**
     * Constructs a new request. The editing domain is derived from the
     * <code>editRequest</code>.
     * 
     * @param editRequest
     *            the edit request whose context is being requested
     */
    public GetEditContextRequest(IEditCommandRequest editRequest,
            Object editHelperContext) {

        this(editRequest.getEditingDomain(), editRequest, editHelperContext);
    }
        

	/**
	 * Gets the edit helper context for this request.
	 */
	public Object getEditHelperContext() {
		IClientContext context = getClientContext();
		
		if (context == null) {
			return editHelperContext;

		} else if (editHelperContext instanceof EObject) {
			return new EditHelperContext((EObject) editHelperContext, context);

		} else if (editHelperContext instanceof IElementType) {
			return new EditHelperContext((IElementType) editHelperContext,
					context);
		}
		
		return editHelperContext;
	}

	/**
	 * Gets the edit command request for which the edit context is being sought.
	 * 
	 * @return the edit command request
	 */
	public IEditCommandRequest getEditCommandRequest() {
		return editRequest;
	}

	/**
	 * Gets the requested edit context.
	 * 
	 * @return the edit context
	 */
	public Object getEditContext() {
		return editContext;
	}

	/**
	 * Sets the requested edit context. Clients asked to get a command for this
	 * request should also set the edit context if the command they will return
	 * will create or return a different context.
	 * 
	 * @param editContext
	 *            the new edit context
	 */
	public void setEditContext(Object editContext) {
		this.editContext = editContext;
	}

}