# How to edit UML element programmatically

Papyrus provides via "GMF runtime" an API to edit UML element.

The modification is related to the command context UNDO/REDO

Papyrus use the FrameworkElementType in order to manage the life cycle.

This framework enables the consistency of UML model and graphical Model.

### Steps

Following is a description of the basic steps

1. Specify the editing domain.
2. Request creation using "GMF request (SetRequest, CreateElementRequest, DestroyRequest, ...) " all this requests implements org.eclipse.gmf.runtime.emf.type.core.requests.IEditCommandRequest
3. Call the provider.

    IElementEditService provider = ElementEditServiceUtils.getCommandProvider(editedElement);
    command = provider.getEditCommand(yourRequest)

### Execution

    domain.getCommandStack().execute(new GMFtoEMFCommandWrapper(command));

### Example to be able to create, destroy, and rename a class

    /*****************************************************************************
     * Copyright (c) 2020 CEA LIST and others.
     *
     * All rights reserved. This program and the accompanying materials
     * are made available under the terms of the Eclipse Public License 2.0
     * which accompanies this distribution, and is available at
     * http://www.eclipse.org/legal/epl-2.0/
     *
     * SPDX-License-Identifier: EPL-2.0
     *
     * Contributors:
     *   CEA LIST - Initial API and implementation
     *
     *****************************************************************************/

    package org.eclipse.papyrus.uml.diagram.clazz.custom.command;

    import org.eclipse.emf.ecore.EObject;
    import org.eclipse.emf.transaction.TransactionalEditingDomain;
    import org.eclipse.emf.transaction.util.TransactionUtil;
    import org.eclipse.gmf.runtime.common.core.command.ICommand;
    import org.eclipse.gmf.runtime.emf.type.core.requests.CreateElementRequest;
    import org.eclipse.gmf.runtime.emf.type.core.requests.DestroyElementRequest;
    import org.eclipse.gmf.runtime.emf.type.core.requests.SetRequest;
    import org.eclipse.papyrus.infra.emf.gmf.command.GMFtoEMFCommandWrapper;
    import org.eclipse.papyrus.infra.services.edit.service.ElementEditServiceUtils;
    import org.eclipse.papyrus.infra.services.edit.service.IElementEditService;
    import org.eclipse.papyrus.uml.service.types.element.UMLElementTypes;
    import org.eclipse.uml2.uml.NamedElement;
    import org.eclipse.uml2.uml.Package;
    import org.eclipse.uml2.uml.UMLPackage;

    /**
     * editing elements example
     */
    public class EditElementExample {

    	/**
    	 * Create a Class in a UML Package
    	 *
    	 * @param pack
    	 *            the package owner
    	 */
    	public static void createAClass(final Package pack) {
    		TransactionalEditingDomain domain = TransactionUtil.getEditingDomain(pack);
    		// create a Class inside a package (here the containment feature is automatically deduced by the framework, but you can specify it
    		CreateElementRequest request = new CreateElementRequest(domain, pack, UMLElementTypes.CLASS);
    		IElementEditService provider = ElementEditServiceUtils.getCommandProvider(pack);
    		ICommand command = provider.getEditCommand(request);
    		domain.getCommandStack().execute(new GMFtoEMFCommandWrapper(command));
    	}

    	/**
    	 * Destroy an element
    	 *
    	 * @param element
    	 *            the element to destroy
    	 */
    	public static void destroyAnElement(final EObject element) {
    		TransactionalEditingDomain domain = TransactionUtil.getEditingDomain(element);
    		DestroyElementRequest request = new DestroyElementRequest(element, false);
    		IElementEditService provider = ElementEditServiceUtils.getCommandProvider(element);
    		ICommand command = provider.getEditCommand(request);
    		domain.getCommandStack().execute(new GMFtoEMFCommandWrapper(command));
    	}

    	/**
    	 * How to rename a NamedElement
    	 *
    	 * @param namedElement
    	 *            the element to rename
    	 * @param newName
    	 *            the new name of the element
    	 */
    	public static void renameANamedElement(final NamedElement namedElement, final String newName) {
    		TransactionalEditingDomain domain = TransactionUtil.getEditingDomain(namedElement);
    		SetRequest request = new SetRequest(namedElement, UMLPackage.eINSTANCE.getNamedElement_Name(), newName);
    		IElementEditService provider = ElementEditServiceUtils.getCommandProvider(namedElement);
    		ICommand command = provider.getEditCommand(request);
    		domain.getCommandStack().execute(new GMFtoEMFCommandWrapper(command));
    	}
    }