bundles/org.eclipse.emf.ecp.ui.view.editor.controls/src/org/eclipse/emf/ecp/view/spi/editor/controls/AbstractFilteredReferenceCommand.java

/*******************************************************************************
 * Copyright (c) 2011-2013 EclipseSource Muenchen GmbH 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
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 * Eugen Neufeld - initial API and implementation
 *
 *******************************************************************************/
package org.eclipse.emf.ecp.view.spi.editor.controls;

import java.lang.reflect.ParameterizedType;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.emf.common.notify.Notifier;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EClassifier;
import org.eclipse.emf.ecore.EPackage;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecp.view.internal.editor.controls.ECPSelectionStatusValidator;
import org.eclipse.emf.ecp.view.internal.editor.controls.ECPViewEditorTreeSelectionDialog;
import org.eclipse.emf.edit.command.ChangeCommand;
import org.eclipse.emf.edit.provider.ComposedAdapterFactory;
import org.eclipse.emf.edit.ui.provider.AdapterFactoryLabelProvider;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.window.Window;
import org.eclipse.swt.widgets.Shell;

/**
 * A ReferenceCommand allowing to select an {@link EStructuralFeature} using a dialog.
 *
 * @author Eugen Neufeld
 *
 * @param <T> type of the {@link EStructuralFeature} which can be selected
 * @since 1.5
 */
public abstract class AbstractFilteredReferenceCommand<T extends EStructuralFeature> extends ChangeCommand {

	private final Shell shell;
	private final ComposedAdapterFactory composedAdapterFactory;
	private final EClass rootClass;
	private final ECPSelectionStatusValidator validator;
	private final boolean allowMultiReferences;

	/**
	 * Constructor for the AbstractFilteredReferenceCommand.
	 *
	 * @param notifier the Notifier for the {@link ChangeCommand}
	 * @param composedAdapterFactory the {@link ComposedAdapterFactory} for the LabelProvider
	 * @param shell the {@link Shell} to use in the dialog
	 * @param rootClass the {@link EClass} which is the root of the view
	 * @param validator the {@link ECPSelectionStatusValidator} to use when a selection was done
	 * @param allowMultiReferences whether multi references are allowed during the selection
	 */
	public AbstractFilteredReferenceCommand(Notifier notifier, ComposedAdapterFactory composedAdapterFactory,
		Shell shell, EClass rootClass, ECPSelectionStatusValidator validator, boolean allowMultiReferences) {
		super(notifier);
		this.shell = shell;
		this.composedAdapterFactory = composedAdapterFactory;

		this.rootClass = rootClass;
		this.validator = validator;
		this.allowMultiReferences = allowMultiReferences;
	}

	private Class<?> returnedClass() {
		final ParameterizedType parameterizedType = (ParameterizedType) getClass().getGenericSuperclass();
		return (Class<?>) parameterizedType.getActualTypeArguments()[0];
	}

	@Override
	protected void doExecute() {
		final AdapterFactoryLabelProvider labelProvider = new AdapterFactoryLabelProvider(composedAdapterFactory);
		final ECPViewEditorTreeSelectionDialog dialog = new ECPViewEditorTreeSelectionDialog(shell, labelProvider,
			new EReferenceTreeContenProvider());
		validator.setECPViewEditorTreeSelectionDialog(dialog);
		dialog.setAllowMultiple(false);
		dialog.setValidator(validator);
		dialog.setInput(rootClass != null ? rootClass : EPackage.Registry.INSTANCE);
		dialog.setMessage("Select a " + returnedClass().getSimpleName());
		dialog.setTitle("Select a " + returnedClass().getSimpleName());
		final int result = dialog.open();
		if (Window.OK == result) {
			final Object selection = dialog.getFirstResult();
			if (returnedClass().isInstance(selection)) {
				final T selectedFeature = (T) selection;

				final List<EReference> bottomUpPath = new ArrayList<EReference>();
				final TreePath path = dialog.getTreePath();

				for (int i = 0; i < path.getSegmentCount() - 1; i++) {
					final Object o = path.getSegment(i);
					if (EReference.class.isInstance(o)) {
						bottomUpPath.add((EReference) o);
					}
				}

				setSelectedValues(selectedFeature, bottomUpPath);
			}
		}
		labelProvider.dispose();
	}

	/**
	 * Template method which is called so that the selected element can be saved.
	 *
	 * @param selectedFeature the {@link EStructuralFeature} to set
	 * @param bottomUpPath the path to the feature
	 */
	protected abstract void setSelectedValues(T selectedFeature, List<EReference> bottomUpPath);

	/**
	 * Content provider for a tree showing all {@link EReference}s within a {@link EClass} or {@link EPackage}.
	 *
	 * @author Jonas Helming
	 *
	 */
	private final class EReferenceTreeContenProvider implements ITreeContentProvider {
		@Override
		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
			// Do nothing (no input change expected/supported)

		}

		@Override
		public void dispose() {
			// Do Nothing, no listeners instanciated
		}

		@Override
		public boolean hasChildren(Object element) {

			if (EPackage.class.isInstance(element)) {
				return true;
			}
			if (EClass.class.isInstance(element)) {
				final EClass eClass = (EClass) element;
				final boolean hasReferences = !eClass.getEAllReferences().isEmpty();
				final boolean hasAttributes = !eClass.getEAllAttributes().isEmpty();
				return hasReferences || hasAttributes;

			}
			if (EReference.class.isInstance(element)) {
				final EReference eReference = (EReference) element;

				return eReference.isMany() && !allowMultiReferences ? false
					: hasChildren(eReference
						.getEReferenceType());
			}
			return false;
		}

		@Override
		public Object getParent(Object element) {
			// TODO Auto-generated method stub
			return null;
		}

		@Override
		public Object[] getElements(Object inputElement) {
			return getChildren(inputElement);
		}

		@Override
		public Object[] getChildren(Object parentElement) {
			if (EClass.class.isInstance(parentElement)) {
				final EClass eClass = (EClass) parentElement;
				final Set<Object> result = getElementsForEClass(eClass);
				return result.toArray();
			}
			if (EReference.class.isInstance(parentElement)) {
				final EReference eReference = (EReference) parentElement;
				final Set<Object> result = getElementsForEClass(eReference.getEReferenceType());
				return result.toArray();
			}
			if (EPackage.Registry.class.isInstance(parentElement)) {
				return EPackage.Registry.class.cast(parentElement).values().toArray();
			}
			if (EPackage.class.isInstance(parentElement)) {
				final Set<Object> children = new LinkedHashSet<Object>();
				children.addAll(EPackage.class.cast(parentElement).getESubpackages());
				children.addAll(EPackage.class.cast(parentElement).getEClassifiers());
				return children.toArray();
			}
			return null;
		}

		private Set<Object> getElementsForEClass(EClass eClass) {
			final Set<Object> result = new LinkedHashSet<Object>();
			if (eClass.isAbstract() || eClass.isInterface()) {
				// find eClasses which are not abstract
				for (final EClassifier eClassifier : eClass.getEPackage().getEClassifiers()) {
					if (eClass != eClassifier && EClass.class.isInstance(eClassifier)
						&& eClass.isSuperTypeOf((EClass) eClassifier)) {
						result.add(eClassifier);
					}
				}
			} else {
				result.addAll(eClass.getEAllReferences());
				result.addAll(eClass.getEAllAttributes());
			}
			return result;
		}
	}

}