bundles/org.eclipse.emf.ecp.view.table.ui.swt/src/org/eclipse/emf/ecp/view/spi/table/swt/ItemProviderEnumCellEditor.java - emfclient/org.eclipse.emf.ecp.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2017-2019 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:
  * Edgar Mueller - initial API and implementation
  * Christian W. Damus - rework for i18n support and code cleanup
  * Lucas Koehler - rework integration
  ******************************************************************************/
 package org.eclipse.emf.ecp.view.spi.table.swt;

 import static java.lang.Math.min;
 import static org.eclipse.emf.ecp.view.internal.table.swt.FigureUtilities.getTextWidth;

 import java.text.MessageFormat;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.stream.Collectors;

 import org.eclipse.core.databinding.Binding;
 import org.eclipse.core.databinding.DataBindingContext;
 import org.eclipse.core.databinding.UpdateValueStrategy;
 import org.eclipse.core.databinding.observable.Observables;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.databinding.observable.value.ValueDiff;
 import org.eclipse.core.databinding.property.INativePropertyListener;
 import org.eclipse.core.databinding.property.ISimplePropertyListener;
 import org.eclipse.core.databinding.property.value.IValueProperty;
 import org.eclipse.core.databinding.property.value.SimpleValueProperty;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.emf.common.util.Enumerator;
 import org.eclipse.emf.databinding.IEMFObservable;
 import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EEnum;
 import org.eclipse.emf.ecore.EEnumLiteral;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecp.common.spi.EMFUtils;
 import org.eclipse.emf.ecp.edit.spi.swt.table.ECPEnumCellEditor;
 import org.eclipse.emf.ecp.view.internal.core.swt.MatchItemComboViewer;
 import org.eclipse.emf.ecp.view.spi.context.ViewModelContext;
 import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
 import org.eclipse.emf.edit.provider.IItemPropertySource;
 import org.eclipse.emfforms.spi.common.BundleResolver;
 import org.eclipse.emfforms.spi.common.BundleResolver.NoBundleFoundException;
 import org.eclipse.emfforms.spi.common.BundleResolverFactory;
 import org.eclipse.emfforms.spi.common.report.AbstractReport;
 import org.eclipse.emfforms.spi.common.report.ReportService;
 import org.eclipse.emfforms.spi.localization.EMFFormsLocalizationService;
 import org.eclipse.jface.databinding.viewers.typed.ViewerProperties;
 import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.ColumnViewerEditorActivationEvent;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.CCombo;
 import org.eclipse.swt.events.FocusEvent;
 import org.eclipse.swt.events.FocusListener;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.osgi.framework.Bundle;

 /**
  * Generic {@link org.eclipse.emf.ecp.edit.spi.swt.table.ECPCellEditor ECPCellEditor} which is
  * applicable for all {@link EAttribute EAttributes} with a Single {@link EEnum} data type.
  * This cell editor uses the EMF.Edit item provider to determine
  * the model's proper choice of values for an {@link EEnum} attribute. Additionally, it filters out enum literals with
  * are marked as <code>isInputtable=false</code> with a custom annotation.
  *
  * @author Christian W. Damus
  * @author Lucas Koehler
  * @since 1.22
  */
 public class ItemProviderEnumCellEditor extends ECPEnumCellEditor {

 	/**
 	 * Template to generate the localization key for an enum value. First parameter is the EEnum's type name, second
 	 * parameter is the value's name.
 	 */
 	private static final String LOCALIZATION_KEY_TEMPLATE = "_UI_%s_%s_literal"; //$NON-NLS-1$

 	private EMFFormsLocalizationService l10n;
 	private MatchItemComboViewer viewer;
 	private int minWidth;

 	private EAttribute attribute;
 	private BundleResolver bundleResolver = BundleResolverFactory.createBundleResolver();
 	/** The edit bundle for the EEnum renderered by this cell editor. */
 	private Optional<Bundle> editBundle;
 	private Optional<EObject> source = Optional.empty();

 	/**
 	 * Initializes me with my parent.
 	 *
 	 * @param parent my parent composite
 	 */
 	public ItemProviderEnumCellEditor(Composite parent) {
 		super(parent);
 	}

 	/**
 	 * Initializes me with my parent and style.
 	 *
 	 * @param parent my parent composite
 	 * @param style my style bits
 	 */
 	public ItemProviderEnumCellEditor(Composite parent, int style) {
 		super(parent, style);
 	}

 	/**
 	 * Initializes me with my parent, style, and custom {@link BundleResolver} and {@link EMFFormsLocalizationService}.
 	 *
 	 * @param parent my parent composite
 	 * @param style my style bits
 	 * @param bundleResolver custom {@link BundleResolver}
 	 * @param l10n custom {@link EMFFormsLocalizationService}
 	 */
 	public ItemProviderEnumCellEditor(Composite parent, int style, BundleResolver bundleResolver,
 		EMFFormsLocalizationService l10n) {
 		this(parent, style);
 		this.bundleResolver = bundleResolver;
 		this.l10n = l10n;
 	}

 	@Override
 	@SuppressWarnings("rawtypes")
 	public UpdateValueStrategy getModelToTargetStrategy(DataBindingContext databindingContext) {
 		return new UpdateValueStrategy() {
 			@Override
 			public Object convert(Object value) {
 				if (!source.isPresent()) {
 					// Extract the source model element from the data binding
 					source = inferSource(databindingContext);
 				}

 				return value;
 			}
 		};
 	}

 	@Override
 	@SuppressWarnings("rawtypes")
 	public UpdateValueStrategy getTargetToModelStrategy(DataBindingContext databindingContext) {
 		return new UpdateValueStrategy();
 	}

 	@Override
 	protected Control createControl(Composite parent) {
 		viewer = new MatchItemComboViewer(new CCombo(parent, SWT.NONE)) {
 			@Override
 			public void onEnter() {
 				super.onEnter();
 				applySelection();
 				focusLost();
 			}

 			@Override
 			protected void onEscape() {
 				fireCancelEditor();
 			}
 		};

 		final CCombo combo = viewer.getCCombo();
 		GridDataFactory.fillDefaults().grab(true, false).applyTo(combo);
 		viewer.setContentProvider(ArrayContentProvider.getInstance());
 		viewer.setLabelProvider(new EnumLabelProvider());
 		combo.addFocusListener(new FocusListener() {

 			@Override
 			public void focusLost(FocusEvent e) {
 				applySelection();
 			}

 			@Override
 			public void focusGained(FocusEvent e) {
 				// nothing to do here
 			}
 		});
 		return combo;
 	}

 	private void applySelection() {
 		final CCombo combo = viewer.getCCombo();
 		final int selection = combo.getSelectionIndex();
 		if (selection >= 0) {
 			final List<?> input = (List<?>) viewer.getInput();
 			viewer.setSelection(new StructuredSelection(input.get(selection)));
 		}
 	}

 	/**
 	 * Gets the proper choice of values provided by the item-provider
 	 * of the source object of our data binding for the attribute that
 	 * is bound. In addition, we remove all choices annotated by our custom annotation.
 	 * <br/>
 	 * If the property descriptor is not available or does not return any choice, the enum's literals minus the
 	 * annotated ones are returned.
 	 *
 	 * @return The available enum values, might be empty but never <code>null</code>
 	 */
 	protected List<?> getChoiceOfValues() {
 		final Collection<?> providerChoices = getPropertyDescriptor()
 			// if the propertyDescriptor is present, we have a source
 			.map(descriptor -> descriptor.getChoiceOfValues(getSource().get()))
 			.orElse(Collections.emptySet());

 		final List<Enumerator> result = getELiterals().stream().map(EEnumLiteral::getInstance)
 			.collect(Collectors.toList());
 		if (!providerChoices.isEmpty()) {
 			result.retainAll(providerChoices);
 		}

 		return result;
 	}

 	@Override
 	public String getFormatedString(Object value) {
 		// If the propertyDescriptor is present, then we have a source
 		return getPropertyDescriptor().map(desc -> desc.getLabelProvider(getSource().get()))
 			.map(lp -> lp.getText(value))
 			.orElseGet(() -> getLabel((Enumerator) value));
 	}

 	private String getLabel(Enumerator enumValue) {
 		final String typeName = attribute.getEType().getName();

 		return editBundle
 			.map(eB -> l10n.getString(eB, String.format(LOCALIZATION_KEY_TEMPLATE, typeName, enumValue.getName())))
 			.orElse(enumValue.getLiteral());
 	}

 	@Override
 	public void instantiate(EStructuralFeature feature, ViewModelContext viewModelContext) {
 		if (l10n == null) {
 			l10n = viewModelContext.getService(EMFFormsLocalizationService.class);
 		}
 		attribute = (EAttribute) feature;

 		try {
 			editBundle = Optional.of(bundleResolver.getEditBundle(feature.getEType()));
 		} catch (final NoBundleFoundException ex) {
 			viewModelContext.getService(ReportService.class)
 				.report(new AbstractReport(
 					MessageFormat.format(
 						"No edit bundle was found for EEnum ''{0}''. Hence, its literals cannot be internationalized for feature ''{1}''.", //$NON-NLS-1$
 						feature.getEType().getName(), feature.getName()),
 					IStatus.WARNING));
 			editBundle = Optional.empty();
 		}

 		final List<?> choices = getChoiceOfValues();
 		viewer.getCCombo().setVisibleItemCount(min(choices.size(), 8));
 		final Point emptyViewerSize = viewer.getCCombo().computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
 		minWidth = choices.stream()
 			.mapToInt(value -> getTextWidth(getFormatedString(value), viewer.getCCombo().getFont()))
 			.reduce(50, Math::max);
 		minWidth += emptyViewerSize.x;
 	}

 	@SuppressWarnings("rawtypes")
 	@Override
 	public IValueProperty getValueProperty() {
 		return new ComboValueProperty();
 	}

 	@Override
 	public void activate(ColumnViewerEditorActivationEvent actEvent) {
 		viewer.setInput(getChoiceOfValues());
 		source.ifPresent(obj -> {
 			viewer.getCCombo().setText(getFormatedString(obj.eGet(attribute)));
 		});

 		super.activate(actEvent);

 		if (actEvent.eventType == ColumnViewerEditorActivationEvent.KEY_PRESSED) {
 			final CCombo control = (CCombo) getControl();
 			if (control != null && Character.isLetterOrDigit(actEvent.character)) {
 				viewer.getBuffer().reset();
 				// key pressed is not fired during activation
 				viewer.getBuffer().addLast(actEvent.character);
 			}
 		}
 	}

 	@Override
 	public void deactivate() {
 		super.deactivate();

 		// Forget the source previously inferred
 		source = Optional.empty();
 	}

 	@Override
 	public int getColumnWidthWeight() {
 		return 100;
 	}

 	@Override
 	public int getMinWidth() {
 		return minWidth;
 	}

 	@Override
 	public EEnum getEEnum() {
 		return (EEnum) attribute.getEType();
 	}

 	@Override
 	public Image getImage(Object value) {
 		return null;
 	}

 	@Override
 	public void setEditable(boolean editable) {
 		viewer.getCCombo().setEnabled(editable);
 	}

 	// Infer the source model element from the EMF binding in the
 	// context that is for our attribute
 	private Optional<EObject> inferSource(DataBindingContext context) {
 		return ((List<?>) context.getBindings()).stream()
 			.map(Binding.class::cast)
 			.map(Binding::getModel)
 			.filter(IEMFObservable.class::isInstance).map(IEMFObservable.class::cast)
 			.filter(obs -> obs.getStructuralFeature() == attribute)
 			.map(IEMFObservable::getObserved)
 			.map(EObject.class::cast) // Can't observe a feature of a non-EObject
 			.findAny();
 	}

 	/**
 	 * @return The current source EObject
 	 */
 	protected Optional<EObject> getSource() {
 		return source;
 	}

 	/**
 	 * @return The {@link IItemPropertyDescriptor} descriptor of the current source if it is available
 	 */
 	protected Optional<IItemPropertyDescriptor> getPropertyDescriptor() {
 		return getSource().flatMap(source -> getPropertyDescriptor(source, attribute.getName()));
 	}

 	@Override
 	protected Object doGetValue() {
 		return viewer.getStructuredSelection().getFirstElement();
 	}

 	@Override
 	protected void doSetValue(Object value) {
 		viewer.setSelection(value == null ? StructuredSelection.EMPTY : new StructuredSelection(value));
 	}

 	@Override
 	protected void doSetFocus() {
 		final CCombo combo = viewer.getCCombo();
 		if (combo == null || combo.isDisposed()) {
 			return;
 		}

 		combo.setFocus();

 		// Remove text selection and move the cursor to the end.
 		final String text = combo.getText();
 		if (text != null) {
 			combo.setSelection(new Point(text.length(), text.length()));
 		}
 	}

 	/**
 	 * Obtains the EMF.Edit property descriptor for the named property of the {@code object}.
 	 *
 	 * @param object an object
 	 * @param propertyName a property to access
 	 * @return its descriptor
 	 */
 	static Optional<IItemPropertyDescriptor> getPropertyDescriptor(EObject object, String propertyName) {
 		return EMFUtils.adapt(object, IItemPropertySource.class)
 			.map(propertySource -> propertySource.getPropertyDescriptor(object, propertyName));
 	}

 	//
 	// Nested types
 	//

 	/**
 	 * Label provider for enumeration values.
 	 */
 	private class EnumLabelProvider extends LabelProvider {
 		EnumLabelProvider() {
 			super();
 		}

 		@Override
 		public String getText(Object element) {
 			return getFormatedString(element);
 		}

 	}

 	/**
 	 * Observable value of the combo.
 	 */
 	private class ComboValueProperty extends SimpleValueProperty<Object, Object> {

 		@Override
 		public Object getValueType() {
 			return CCombo.class;
 		}

 		@Override
 		protected Object doGetValue(Object source) {
 			return ItemProviderEnumCellEditor.this.getValue();
 		}

 		@Override
 		protected void doSetValue(Object source, Object value) {
 			ItemProviderEnumCellEditor.this.doSetValue(value);
 		}

 		@Override
 		public IObservableValue<Object> observe(Object source) {
 			if (source != ItemProviderEnumCellEditor.this) {
 				return Observables.constantObservableValue(null);
 			}

 			return ViewerProperties.singleSelection().observe(viewer);
 		}

 		@Override
 		public INativePropertyListener<Object> adaptListener(
 			ISimplePropertyListener<Object, ValueDiff<? extends Object>> listener) {
 			return null;
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2017-2019 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:
	* Edgar Mueller - initial API and implementation
	* Christian W. Damus - rework for i18n support and code cleanup
	* Lucas Koehler - rework integration
	******************************************************************************/
	package org.eclipse.emf.ecp.view.spi.table.swt;

	import static java.lang.Math.min;
	import static org.eclipse.emf.ecp.view.internal.table.swt.FigureUtilities.getTextWidth;

	import java.text.MessageFormat;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.List;
	import java.util.Optional;
	import java.util.stream.Collectors;

	import org.eclipse.core.databinding.Binding;
	import org.eclipse.core.databinding.DataBindingContext;
	import org.eclipse.core.databinding.UpdateValueStrategy;
	import org.eclipse.core.databinding.observable.Observables;
	import org.eclipse.core.databinding.observable.value.IObservableValue;
	import org.eclipse.core.databinding.observable.value.ValueDiff;
	import org.eclipse.core.databinding.property.INativePropertyListener;
	import org.eclipse.core.databinding.property.ISimplePropertyListener;
	import org.eclipse.core.databinding.property.value.IValueProperty;
	import org.eclipse.core.databinding.property.value.SimpleValueProperty;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.emf.common.util.Enumerator;
	import org.eclipse.emf.databinding.IEMFObservable;
	import org.eclipse.emf.ecore.EAttribute;
	import org.eclipse.emf.ecore.EEnum;
	import org.eclipse.emf.ecore.EEnumLiteral;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.ecore.EStructuralFeature;
	import org.eclipse.emf.ecp.common.spi.EMFUtils;
	import org.eclipse.emf.ecp.edit.spi.swt.table.ECPEnumCellEditor;
	import org.eclipse.emf.ecp.view.internal.core.swt.MatchItemComboViewer;
	import org.eclipse.emf.ecp.view.spi.context.ViewModelContext;
	import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
	import org.eclipse.emf.edit.provider.IItemPropertySource;
	import org.eclipse.emfforms.spi.common.BundleResolver;
	import org.eclipse.emfforms.spi.common.BundleResolver.NoBundleFoundException;
	import org.eclipse.emfforms.spi.common.BundleResolverFactory;
	import org.eclipse.emfforms.spi.common.report.AbstractReport;
	import org.eclipse.emfforms.spi.common.report.ReportService;
	import org.eclipse.emfforms.spi.localization.EMFFormsLocalizationService;
	import org.eclipse.jface.databinding.viewers.typed.ViewerProperties;
	import org.eclipse.jface.layout.GridDataFactory;
	import org.eclipse.jface.viewers.ArrayContentProvider;
	import org.eclipse.jface.viewers.ColumnViewerEditorActivationEvent;
	import org.eclipse.jface.viewers.LabelProvider;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.CCombo;
	import org.eclipse.swt.events.FocusEvent;
	import org.eclipse.swt.events.FocusListener;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.osgi.framework.Bundle;

	/**
	* Generic {@link org.eclipse.emf.ecp.edit.spi.swt.table.ECPCellEditor ECPCellEditor} which is
	* applicable for all {@link EAttribute EAttributes} with a Single {@link EEnum} data type.
	* This cell editor uses the EMF.Edit item provider to determine
	* the model's proper choice of values for an {@link EEnum} attribute. Additionally, it filters out enum literals with
	* are marked as <code>isInputtable=false</code> with a custom annotation.
	*
	* @author Christian W. Damus
	* @author Lucas Koehler
	* @since 1.22
	*/
	public class ItemProviderEnumCellEditor extends ECPEnumCellEditor {

	/**
	* Template to generate the localization key for an enum value. First parameter is the EEnum's type name, second
	* parameter is the value's name.
	*/
	private static final String LOCALIZATION_KEY_TEMPLATE = "_UI_%s_%s_literal"; //$NON-NLS-1$

	private EMFFormsLocalizationService l10n;
	private MatchItemComboViewer viewer;
	private int minWidth;

	private EAttribute attribute;
	private BundleResolver bundleResolver = BundleResolverFactory.createBundleResolver();
	/** The edit bundle for the EEnum renderered by this cell editor. */
	private Optional<Bundle> editBundle;
	private Optional<EObject> source = Optional.empty();

	/**
	* Initializes me with my parent.
	*
	* @param parent my parent composite
	*/
	public ItemProviderEnumCellEditor(Composite parent) {
	super(parent);
	}

	/**
	* Initializes me with my parent and style.
	*
	* @param parent my parent composite
	* @param style my style bits
	*/
	public ItemProviderEnumCellEditor(Composite parent, int style) {
	super(parent, style);
	}

	/**
	* Initializes me with my parent, style, and custom {@link BundleResolver} and {@link EMFFormsLocalizationService}.
	*
	* @param parent my parent composite
	* @param style my style bits
	* @param bundleResolver custom {@link BundleResolver}
	* @param l10n custom {@link EMFFormsLocalizationService}
	*/
	public ItemProviderEnumCellEditor(Composite parent, int style, BundleResolver bundleResolver,
	EMFFormsLocalizationService l10n) {
	this(parent, style);
	this.bundleResolver = bundleResolver;
	this.l10n = l10n;
	}

	@Override
	@SuppressWarnings("rawtypes")
	public UpdateValueStrategy getModelToTargetStrategy(DataBindingContext databindingContext) {
	return new UpdateValueStrategy() {
	@Override
	public Object convert(Object value) {
	if (!source.isPresent()) {
	// Extract the source model element from the data binding
	source = inferSource(databindingContext);
	}

	return value;
	}
	};
	}

	@Override
	@SuppressWarnings("rawtypes")
	public UpdateValueStrategy getTargetToModelStrategy(DataBindingContext databindingContext) {
	return new UpdateValueStrategy();
	}

	@Override
	protected Control createControl(Composite parent) {
	viewer = new MatchItemComboViewer(new CCombo(parent, SWT.NONE)) {
	@Override
	public void onEnter() {
	super.onEnter();
	applySelection();
	focusLost();
	}

	@Override
	protected void onEscape() {
	fireCancelEditor();
	}
	};

	final CCombo combo = viewer.getCCombo();
	GridDataFactory.fillDefaults().grab(true, false).applyTo(combo);
	viewer.setContentProvider(ArrayContentProvider.getInstance());
	viewer.setLabelProvider(new EnumLabelProvider());
	combo.addFocusListener(new FocusListener() {

	@Override
	public void focusLost(FocusEvent e) {
	applySelection();
	}

	@Override
	public void focusGained(FocusEvent e) {
	// nothing to do here
	}
	});
	return combo;
	}

	private void applySelection() {
	final CCombo combo = viewer.getCCombo();
	final int selection = combo.getSelectionIndex();
	if (selection >= 0) {
	final List<?> input = (List<?>) viewer.getInput();
	viewer.setSelection(new StructuredSelection(input.get(selection)));
	}
	}

	/**
	* Gets the proper choice of values provided by the item-provider
	* of the source object of our data binding for the attribute that
	* is bound. In addition, we remove all choices annotated by our custom annotation.
	* <br/>
	* If the property descriptor is not available or does not return any choice, the enum's literals minus the
	* annotated ones are returned.
	*
	* @return The available enum values, might be empty but never <code>null</code>
	*/
	protected List<?> getChoiceOfValues() {
	final Collection<?> providerChoices = getPropertyDescriptor()
	// if the propertyDescriptor is present, we have a source
	.map(descriptor -> descriptor.getChoiceOfValues(getSource().get()))
	.orElse(Collections.emptySet());

	final List<Enumerator> result = getELiterals().stream().map(EEnumLiteral::getInstance)
	.collect(Collectors.toList());
	if (!providerChoices.isEmpty()) {
	result.retainAll(providerChoices);
	}

	return result;
	}

	@Override
	public String getFormatedString(Object value) {
	// If the propertyDescriptor is present, then we have a source
	return getPropertyDescriptor().map(desc -> desc.getLabelProvider(getSource().get()))
	.map(lp -> lp.getText(value))
	.orElseGet(() -> getLabel((Enumerator) value));
	}

	private String getLabel(Enumerator enumValue) {
	final String typeName = attribute.getEType().getName();

	return editBundle
	.map(eB -> l10n.getString(eB, String.format(LOCALIZATION_KEY_TEMPLATE, typeName, enumValue.getName())))
	.orElse(enumValue.getLiteral());
	}

	@Override
	public void instantiate(EStructuralFeature feature, ViewModelContext viewModelContext) {
	if (l10n == null) {
	l10n = viewModelContext.getService(EMFFormsLocalizationService.class);
	}
	attribute = (EAttribute) feature;

	try {
	editBundle = Optional.of(bundleResolver.getEditBundle(feature.getEType()));
	} catch (final NoBundleFoundException ex) {
	viewModelContext.getService(ReportService.class)
	.report(new AbstractReport(
	MessageFormat.format(
	"No edit bundle was found for EEnum ''{0}''. Hence, its literals cannot be internationalized for feature ''{1}''.", //$NON-NLS-1$
	feature.getEType().getName(), feature.getName()),
	IStatus.WARNING));
	editBundle = Optional.empty();
	}

	final List<?> choices = getChoiceOfValues();
	viewer.getCCombo().setVisibleItemCount(min(choices.size(), 8));
	final Point emptyViewerSize = viewer.getCCombo().computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
	minWidth = choices.stream()
	.mapToInt(value -> getTextWidth(getFormatedString(value), viewer.getCCombo().getFont()))
	.reduce(50, Math::max);
	minWidth += emptyViewerSize.x;
	}

	@SuppressWarnings("rawtypes")
	@Override
	public IValueProperty getValueProperty() {
	return new ComboValueProperty();
	}

	@Override
	public void activate(ColumnViewerEditorActivationEvent actEvent) {
	viewer.setInput(getChoiceOfValues());
	source.ifPresent(obj -> {
	viewer.getCCombo().setText(getFormatedString(obj.eGet(attribute)));
	});

	super.activate(actEvent);

	if (actEvent.eventType == ColumnViewerEditorActivationEvent.KEY_PRESSED) {
	final CCombo control = (CCombo) getControl();
	if (control != null && Character.isLetterOrDigit(actEvent.character)) {
	viewer.getBuffer().reset();
	// key pressed is not fired during activation
	viewer.getBuffer().addLast(actEvent.character);
	}
	}
	}

	@Override
	public void deactivate() {
	super.deactivate();

	// Forget the source previously inferred
	source = Optional.empty();
	}

	@Override
	public int getColumnWidthWeight() {
	return 100;
	}

	@Override
	public int getMinWidth() {
	return minWidth;
	}

	@Override
	public EEnum getEEnum() {
	return (EEnum) attribute.getEType();
	}

	@Override
	public Image getImage(Object value) {
	return null;
	}

	@Override
	public void setEditable(boolean editable) {
	viewer.getCCombo().setEnabled(editable);
	}

	// Infer the source model element from the EMF binding in the
	// context that is for our attribute
	private Optional<EObject> inferSource(DataBindingContext context) {
	return ((List<?>) context.getBindings()).stream()
	.map(Binding.class::cast)
	.map(Binding::getModel)
	.filter(IEMFObservable.class::isInstance).map(IEMFObservable.class::cast)
	.filter(obs -> obs.getStructuralFeature() == attribute)
	.map(IEMFObservable::getObserved)
	.map(EObject.class::cast) // Can't observe a feature of a non-EObject
	.findAny();
	}

	/**
	* @return The current source EObject
	*/
	protected Optional<EObject> getSource() {
	return source;
	}

	/**
	* @return The {@link IItemPropertyDescriptor} descriptor of the current source if it is available
	*/
	protected Optional<IItemPropertyDescriptor> getPropertyDescriptor() {
	return getSource().flatMap(source -> getPropertyDescriptor(source, attribute.getName()));
	}

	@Override
	protected Object doGetValue() {
	return viewer.getStructuredSelection().getFirstElement();
	}

	@Override
	protected void doSetValue(Object value) {
	viewer.setSelection(value == null ? StructuredSelection.EMPTY : new StructuredSelection(value));
	}

	@Override
	protected void doSetFocus() {
	final CCombo combo = viewer.getCCombo();
	if (combo == null \|\| combo.isDisposed()) {
	return;
	}

	combo.setFocus();

	// Remove text selection and move the cursor to the end.
	final String text = combo.getText();
	if (text != null) {
	combo.setSelection(new Point(text.length(), text.length()));
	}
	}

	/**
	* Obtains the EMF.Edit property descriptor for the named property of the {@code object}.
	*
	* @param object an object
	* @param propertyName a property to access
	* @return its descriptor
	*/
	static Optional<IItemPropertyDescriptor> getPropertyDescriptor(EObject object, String propertyName) {
	return EMFUtils.adapt(object, IItemPropertySource.class)
	.map(propertySource -> propertySource.getPropertyDescriptor(object, propertyName));
	}

	//
	// Nested types
	//

	/**
	* Label provider for enumeration values.
	*/
	private class EnumLabelProvider extends LabelProvider {
	EnumLabelProvider() {
	super();
	}

	@Override
	public String getText(Object element) {
	return getFormatedString(element);
	}

	}

	/**
	* Observable value of the combo.
	*/
	private class ComboValueProperty extends SimpleValueProperty<Object, Object> {

	@Override
	public Object getValueType() {
	return CCombo.class;
	}

	@Override
	protected Object doGetValue(Object source) {
	return ItemProviderEnumCellEditor.this.getValue();
	}

	@Override
	protected void doSetValue(Object source, Object value) {
	ItemProviderEnumCellEditor.this.doSetValue(value);
	}

	@Override
	public IObservableValue<Object> observe(Object source) {
	if (source != ItemProviderEnumCellEditor.this) {
	return Observables.constantObservableValue(null);
	}

	return ViewerProperties.singleSelection().observe(viewer);
	}

	@Override
	public INativePropertyListener<Object> adaptListener(
	ISimplePropertyListener<Object, ValueDiff<? extends Object>> listener) {
	return null;
	}
	}

	}