bundles/org.eclipse.emfforms.core.services.emf/src/org/eclipse/emfforms/internal/core/services/databinding/EMFFormsDatabindingImpl.java - emfclient/org.eclipse.emf.ecp.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2011-2018 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:
  * Lucas Koehler - initial API and implementation
  * Eugen Neufeld - changed interface to EMFFormsDatabindingEMF
  * Lucas Koehler - Added support for DMR Segments
  ******************************************************************************/
 package org.eclipse.emfforms.internal.core.services.databinding;

 import java.util.LinkedHashSet;
 import java.util.Optional;
 import java.util.Set;

 import org.eclipse.core.databinding.observable.Realm;
 import org.eclipse.core.databinding.observable.list.IObservableList;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.databinding.property.list.IListProperty;
 import org.eclipse.emf.common.util.EList;
 import org.eclipse.emf.databinding.IEMFListProperty;
 import org.eclipse.emf.databinding.IEMFObservable;
 import org.eclipse.emf.databinding.IEMFValueProperty;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.EStructuralFeature.Setting;
 import org.eclipse.emf.ecp.common.spi.asserts.Assert;
 import org.eclipse.emf.ecp.view.spi.model.VDomainModelReference;
 import org.eclipse.emf.ecp.view.spi.model.VDomainModelReferenceSegment;
 import org.eclipse.emf.edit.domain.AdapterFactoryEditingDomain;
 import org.eclipse.emf.edit.domain.EditingDomain;
 import org.eclipse.emfforms.common.RankingHelper;
 import org.eclipse.emfforms.spi.core.services.databinding.DatabindingFailedException;
 import org.eclipse.emfforms.spi.core.services.databinding.DomainModelReferenceConverter;
 import org.eclipse.emfforms.spi.core.services.databinding.EMFFormsDatabinding;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.DomainModelReferenceConverterEMF;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.DomainModelReferenceSegmentConverterEMF;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.EMFFormsDatabindingEMF;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.EMFFormsSegmentResolver;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.SegmentConverterListResultEMF;
 import org.eclipse.emfforms.spi.core.services.databinding.emf.SegmentConverterValueResultEMF;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Reference;
 import org.osgi.service.component.annotations.ReferenceCardinality;
 import org.osgi.service.component.annotations.ReferencePolicy;

 /**
  * EMF implementation of {@link EMFFormsDatabindingEMF}.
  *
  * @author Lucas Koehler
  *
  */
 @Component(name = "databindingService", service = { EMFFormsDatabinding.class, EMFFormsDatabindingEMF.class,
 	EMFFormsSegmentResolver.class })
 public class EMFFormsDatabindingImpl implements EMFFormsDatabindingEMF, EMFFormsSegmentResolver {

 	private static final RankingHelper<DomainModelReferenceConverterEMF> DMR_RANKING_HELPER = //
 		new RankingHelper<DomainModelReferenceConverterEMF>(
 			DomainModelReferenceConverter.class,
 			DomainModelReferenceConverter.NOT_APPLICABLE,
 			DomainModelReferenceConverter.NOT_APPLICABLE);

 	private static final RankingHelper<DomainModelReferenceSegmentConverterEMF> SEGMENTS_RANKING_HELPER = //
 		new RankingHelper<>(
 			DomainModelReferenceSegmentConverterEMF.class,
 			DomainModelReferenceSegmentConverterEMF.NOT_APPLICABLE,
 			DomainModelReferenceSegmentConverterEMF.NOT_APPLICABLE);

 	private final Set<DomainModelReferenceConverterEMF> referenceConverters = new LinkedHashSet<>();
 	private final Set<DomainModelReferenceSegmentConverterEMF> segmentConverters = new LinkedHashSet<>();

 	/**
 	 * Adds the given {@link DomainModelReferenceSegmentConverterEMF} to the Set of segment converters.
 	 *
 	 * @param converter The {@link DomainModelReferenceSegmentConverterEMF} to add
 	 */
 	@Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC)
 	protected void addDomainModelReferenceSegmentConverter(DomainModelReferenceSegmentConverterEMF converter) {
 		segmentConverters.add(converter);
 	}

 	/**
 	 * Removes the given {@link DomainModelReferenceSegmentConverterEMF} from the Set of segment converters.
 	 *
 	 * @param converter The {@link DomainModelReferenceSegmentConverterEMF} to remove
 	 */
 	protected void removeDomainModelReferenceSegmentConverter(DomainModelReferenceSegmentConverterEMF converter) {
 		segmentConverters.remove(converter);
 	}

 	@Override
 	public IObservableValue getObservableValue(VDomainModelReference domainModelReference, EObject object)
 		throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();
 		Assert.create(object).notNull();

 		final IEMFValueProperty valueProperty = getValueProperty(domainModelReference, object);
 		final Realm realm = Realm.getDefault();
 		if (realm != null) {
 			return valueProperty.observe(object);
 		}
 		final DefaultRealm dr = new DefaultRealm();
 		final IObservableValue observableValue = valueProperty.observe(object);
 		dr.dispose();
 		return observableValue;
 	}

 	@Override
 	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EObject object)
 		throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();

 		final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
 		if (segments.isEmpty()) {
 			// No segments => Fall back to legacy dmr resolving
 			final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
 				domainModelReference);
 			return bestConverter.convertToValueProperty(domainModelReference, object);
 		}

 		Assert.create(object).notNull();
 		final EditingDomain editingDomain = getEditingDomain(object);
 		return internalGetValueProperty(domainModelReference, object.eClass(), editingDomain);
 	}

 	@Override
 	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EClass rootEClass)
 		throws DatabindingFailedException {
 		return getValueProperty(domainModelReference, rootEClass, null);
 	}

 	@Override
 	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EClass rootEClass,
 		EditingDomain editingDomain) throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();

 		final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
 		if (segments.isEmpty()) {
 			// No segments => Fall back to legacy dmr resolving
 			final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
 				domainModelReference);
 			return bestConverter.convertToValueProperty(domainModelReference, rootEClass, editingDomain);
 		}

 		Assert.create(rootEClass).notNull();
 		return internalGetValueProperty(domainModelReference, rootEClass, editingDomain);
 	}

 	/**
 	 * Actual calculation of a value property using {@link VDomainModelReferenceSegment segments}.
 	 *
 	 * @param domainModelReference The domain model reference pointing to the desired value
 	 * @param rootEClass The root EClass of the rendered form
 	 * @param editingDomain The {@link EditingDomain} of the resulting value property, may be null
 	 * @return The resulting {@link IEMFValueProperty}
 	 * @throws DatabindingFailedException
 	 */
 	private IEMFValueProperty internalGetValueProperty(VDomainModelReference domainModelReference, EClass rootEClass,
 		EditingDomain editingDomain) throws DatabindingFailedException {

 		final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();

 		// Get value property for the (always present) first segment
 		final DomainModelReferenceSegmentConverterEMF firstConverter = getBestDomainModelReferenceSegmentConverter(
 			segments.get(0));
 		SegmentConverterValueResultEMF converterResult = firstConverter.convertToValueProperty(segments.get(0),
 			rootEClass, editingDomain);
 		IEMFValueProperty resultProperty = converterResult.getValueProperty();

 		// Iterate over all remaining segments and get the value properties for their corresponding EClasses.
 		for (int i = 1; i < segments.size(); i++) {
 			final EClass nextEClass = unpackNextEClass(converterResult.getNextEClass(), domainModelReference,
 				segments.get(i));
 			final VDomainModelReferenceSegment segment = segments.get(i);

 			final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
 				segment);
 			converterResult = bestConverter.convertToValueProperty(segment,
 				nextEClass, editingDomain);
 			final IEMFValueProperty nextProperty = converterResult.getValueProperty();
 			// Chain the properties together
 			resultProperty = resultProperty.value(nextProperty);
 		}

 		return resultProperty;
 	}

 	/**
 	 * Adds the given {@link DomainModelReferenceConverterEMF} to the Set of reference converters.
 	 *
 	 * @param converter The {@link DomainModelReferenceConverterEMF} to add
 	 */
 	@Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC)
 	protected void addDomainModelReferenceConverter(DomainModelReferenceConverterEMF converter) {
 		referenceConverters.add(converter);
 	}

 	/**
 	 * Removes the given {@link DomainModelReferenceConverterEMF} to the Set of reference converters.
 	 *
 	 * @param converter The {@link DomainModelReferenceConverterEMF} to remove
 	 */
 	protected void removeDomainModelReferenceConverter(DomainModelReferenceConverterEMF converter) {
 		referenceConverters.remove(converter);
 	}

 	@Override
 	public IObservableList getObservableList(VDomainModelReference domainModelReference, EObject object)
 		throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();
 		Assert.create(object).notNull();

 		final IListProperty listProperty = getListProperty(domainModelReference, object);
 		final Realm realm = Realm.getDefault();
 		if (realm != null) {
 			return listProperty.observe(object);
 		}
 		final DefaultRealm dr = new DefaultRealm();
 		final IObservableList observableList = listProperty.observe(object);
 		dr.dispose();
 		return observableList;
 	}

 	@Override
 	public IEMFListProperty getListProperty(VDomainModelReference domainModelReference, EObject object)
 		throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();

 		final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
 		if (segments.isEmpty()) {
 			// No segments => Fall back to legacy dmr resolving
 			final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
 				domainModelReference);
 			return bestConverter.convertToListProperty(domainModelReference, object);
 		}

 		Assert.create(object).notNull();
 		final EditingDomain editingDomain = getEditingDomain(object);

 		// If there is only one segment, get its list property. Otherwise, get its value property
 		final DomainModelReferenceSegmentConverterEMF firstConverter = getBestDomainModelReferenceSegmentConverter(
 			segments.get(0));
 		if (segments.size() == 1) {
 			// If there is only one segment, directly return its list property
 			return firstConverter.convertToListProperty(segments.get(0), object.eClass(), editingDomain)
 				.getListProperty();
 		}

 		final SegmentConverterValueResultEMF converterResult = firstConverter.convertToValueProperty(segments.get(0),
 			object.eClass(), editingDomain);
 		IEMFValueProperty valueProperty = converterResult.getValueProperty();

 		/*
 		 * Iterate over all "middle" segments and get the value properties for their corresponding EClasses.
 		 * Get the EClass by getting the target EClass of the EReference from the value property of the previously
 		 * resolved segment.
 		 */
 		EClass nextEClass = unpackNextEClass(converterResult.getNextEClass(), domainModelReference, segments.get(0));
 		for (int i = 1; i < segments.size() - 1; i++) {
 			final VDomainModelReferenceSegment segment = segments.get(i);

 			final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
 				segment);
 			final SegmentConverterValueResultEMF nextConverterResult = bestConverter.convertToValueProperty(segment,
 				nextEClass, editingDomain);
 			final IEMFValueProperty nextProperty = nextConverterResult.getValueProperty();

 			nextEClass = unpackNextEClass(nextConverterResult.getNextEClass(), domainModelReference, segment);
 			// Chain the properties together
 			valueProperty = valueProperty.value(nextProperty);
 		}

 		// Get the list property for the last segment
 		final int lastIndex = segments.size() - 1;
 		final DomainModelReferenceSegmentConverterEMF lastConverter = getBestDomainModelReferenceSegmentConverter(
 			segments.get(lastIndex));
 		final SegmentConverterListResultEMF converterListResult = lastConverter.convertToListProperty(
 			segments.get(lastIndex), nextEClass,
 			editingDomain);

 		return valueProperty.list(converterListResult.getListProperty());
 	}

 	/**
 	 * Returns the most suitable {@link DomainModelReferenceConverter}, that is registered to this
 	 * {@link EMFFormsDatabindingImpl}, for the given {@link VDomainModelReference}.
 	 *
 	 * @param domainModelReference The {@link VDomainModelReference} for which a {@link DomainModelReferenceConverter}
 	 *            is needed
 	 * @return The most suitable {@link DomainModelReferenceConverter}
 	 * @throws DatabindingFailedException If no applicable DMR Converter was found
 	 */
 	private DomainModelReferenceConverterEMF getBestDomainModelReferenceConverter(
 		final VDomainModelReference domainModelReference) throws DatabindingFailedException {
 		if (domainModelReference == null) {
 			throw new IllegalArgumentException("The given VDomainModelReference must not be null."); //$NON-NLS-1$
 		}

 		final DomainModelReferenceConverterEMF bestConverter = DMR_RANKING_HELPER.getHighestRankingElement(
 			referenceConverters, converter -> converter.isApplicable(domainModelReference));
 		if (bestConverter == null) {
 			throw new DatabindingFailedException("No applicable DomainModelReferenceConverter could be found."); //$NON-NLS-1$
 		}
 		return bestConverter;
 	}

 	@Override
 	public EStructuralFeature extractFeature(IObservableValue observableValue) throws DatabindingFailedException {
 		if (IEMFObservable.class.isInstance(observableValue)) {
 			return IEMFObservable.class.cast(observableValue).getStructuralFeature();
 		}
 		throw new DatabindingFailedException(
 			String.format("The IObservableValue class %1$s is not supported!", observableValue.getClass().getName())); //$NON-NLS-1$
 	}

 	@Override
 	public EStructuralFeature extractFeature(IObservableList observableList) throws DatabindingFailedException {
 		if (IEMFObservable.class.isInstance(observableList)) {
 			return IEMFObservable.class.cast(observableList).getStructuralFeature();
 		}
 		throw new DatabindingFailedException(
 			String.format("The IObservableList class %1$s is not supported!", observableList.getClass().getName())); //$NON-NLS-1$
 	}

 	@Override
 	public EObject extractObserved(IObservableValue observableValue) throws DatabindingFailedException {
 		if (IEMFObservable.class.isInstance(observableValue)) {
 			return (EObject) IEMFObservable.class.cast(observableValue).getObserved();
 		}
 		throw new DatabindingFailedException(
 			String.format("The IObservableValue class %1$s is not supported!", observableValue.getClass().getName())); //$NON-NLS-1$
 	}

 	@Override
 	public EObject extractObserved(IObservableList observableList) throws DatabindingFailedException {
 		if (IEMFObservable.class.isInstance(observableList)) {
 			return (EObject) IEMFObservable.class.cast(observableList).getObserved();
 		}
 		throw new DatabindingFailedException(
 			String.format("The IObservableList class %1$s is not supported!", observableList.getClass().getName())); //$NON-NLS-1$
 	}

 	@Override
 	public Setting getSetting(VDomainModelReference domainModelReference, EObject object)
 		throws DatabindingFailedException {
 		Assert.create(domainModelReference).notNull();
 		Assert.create(object).notNull();

 		final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
 		if (segments.isEmpty()) {
 			// No segments => Fall back to legacy dmr resolving
 			final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
 				domainModelReference);
 			final Realm realm = Realm.getDefault();
 			if (realm != null) {
 				return bestConverter.getSetting(domainModelReference, object);
 			}
 			final DefaultRealm dr = new DefaultRealm();
 			final Setting setting = bestConverter.getSetting(domainModelReference, object);
 			dr.dispose();
 			return setting;
 		}

 		Setting setting = resolveSegment(segments.get(0), object);

 		/*
 		 * If present, iterate over the remaining segments. For every iteration step, use the resolved EObject of the
 		 * previously resolved Setting in order to resolve the next Setting.
 		 */
 		for (int i = 1; i < segments.size(); i++) {
 			final VDomainModelReferenceSegment segment = segments.get(i);
 			final Object nextObject = setting.get(true);

 			if (!EObject.class.isInstance(nextObject)) {
 				throw new DatabindingFailedException(
 					String.format(
 						"The Setting could not be fully resolved because an intermediate Object was no EObject or was null. " //$NON-NLS-1$
 							+ "The DMR was %1$s. The last resolved segment was %2$s. The root EObject was %3$s.", //$NON-NLS-1$
 						domainModelReference, segments.get(i - 1), object));
 			}

 			final EObject nextEObject = (EObject) nextObject;
 			setting = resolveSegment(segment, nextEObject);
 		}

 		return setting;
 	}

 	/**
 	 * Returns the most suitable {@link DomainModelReferenceSegmentConverterEMF}, that is registered to this
 	 * {@link EMFFormsDatabindingImpl}, for the given {@link VDomainModelReferenceSegment}.
 	 *
 	 * @param segment The {@link VDomainModelReferenceSegment} for which a
 	 *            {@link DomainModelReferenceSegmentConverterEMF}
 	 *            is needed
 	 * @return The most suitable {@link DomainModelReferenceSegmentConverterEMF}, does not return <code>null</code>
 	 * @throws DatabindingFailedException if no suitable segment converter could be found
 	 */
 	private DomainModelReferenceSegmentConverterEMF getBestDomainModelReferenceSegmentConverter(
 		final VDomainModelReferenceSegment segment) throws DatabindingFailedException {

 		final DomainModelReferenceSegmentConverterEMF bestConverter = SEGMENTS_RANKING_HELPER.getHighestRankingElement(
 			segmentConverters, converter -> converter.isApplicable(segment));

 		if (bestConverter == null) {
 			throw new DatabindingFailedException(String
 				.format("No suitable DomainModelReferenceSegmentConverter could be found for segment %1$s", segment)); //$NON-NLS-1$
 		}
 		return bestConverter;

 	}

 	/**
 	 * Unpacks the given {@link EClass} Optional and throws an exception if it is not present.
 	 *
 	 * @param nextEClass the {@link EClass} to check
 	 * @param domainModelReference only needed for exception description
 	 * @param segment only needed for exception description
 	 * @return the unpacked {@link EClass}
 	 * @throws DatabindingFailedException if the next EClass is <code>null</code>
 	 */
 	private EClass unpackNextEClass(final Optional<EClass> nextEClass, VDomainModelReference domainModelReference,
 		final VDomainModelReferenceSegment segment) throws DatabindingFailedException {
 		return nextEClass.orElseThrow(() -> new DatabindingFailedException(String.format(
 			"The Segment [%1$s] could not be resolved because this segment's root EClass" //$NON-NLS-1$
 				+ " could not be resolved from the preceding segment. The DMR is %2$s.", //$NON-NLS-1$
 			segment, domainModelReference)));
 	}

 	private EditingDomain getEditingDomain(EObject object) throws DatabindingFailedException {
 		return AdapterFactoryEditingDomain.getEditingDomainFor(object);
 	}

 	@Override
 	public Setting resolveSegment(VDomainModelReferenceSegment segment, EObject domainObject)
 		throws DatabindingFailedException {
 		final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
 			segment);
 		return bestConverter.getSetting(segment, domainObject);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2011-2018 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:
	* Lucas Koehler - initial API and implementation
	* Eugen Neufeld - changed interface to EMFFormsDatabindingEMF
	* Lucas Koehler - Added support for DMR Segments
	******************************************************************************/
	package org.eclipse.emfforms.internal.core.services.databinding;

	import java.util.LinkedHashSet;
	import java.util.Optional;
	import java.util.Set;

	import org.eclipse.core.databinding.observable.Realm;
	import org.eclipse.core.databinding.observable.list.IObservableList;
	import org.eclipse.core.databinding.observable.value.IObservableValue;
	import org.eclipse.core.databinding.property.list.IListProperty;
	import org.eclipse.emf.common.util.EList;
	import org.eclipse.emf.databinding.IEMFListProperty;
	import org.eclipse.emf.databinding.IEMFObservable;
	import org.eclipse.emf.databinding.IEMFValueProperty;
	import org.eclipse.emf.ecore.EClass;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.ecore.EStructuralFeature;
	import org.eclipse.emf.ecore.EStructuralFeature.Setting;
	import org.eclipse.emf.ecp.common.spi.asserts.Assert;
	import org.eclipse.emf.ecp.view.spi.model.VDomainModelReference;
	import org.eclipse.emf.ecp.view.spi.model.VDomainModelReferenceSegment;
	import org.eclipse.emf.edit.domain.AdapterFactoryEditingDomain;
	import org.eclipse.emf.edit.domain.EditingDomain;
	import org.eclipse.emfforms.common.RankingHelper;
	import org.eclipse.emfforms.spi.core.services.databinding.DatabindingFailedException;
	import org.eclipse.emfforms.spi.core.services.databinding.DomainModelReferenceConverter;
	import org.eclipse.emfforms.spi.core.services.databinding.EMFFormsDatabinding;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.DomainModelReferenceConverterEMF;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.DomainModelReferenceSegmentConverterEMF;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.EMFFormsDatabindingEMF;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.EMFFormsSegmentResolver;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.SegmentConverterListResultEMF;
	import org.eclipse.emfforms.spi.core.services.databinding.emf.SegmentConverterValueResultEMF;
	import org.osgi.service.component.annotations.Component;
	import org.osgi.service.component.annotations.Reference;
	import org.osgi.service.component.annotations.ReferenceCardinality;
	import org.osgi.service.component.annotations.ReferencePolicy;

	/**
	* EMF implementation of {@link EMFFormsDatabindingEMF}.
	*
	* @author Lucas Koehler
	*
	*/
	@Component(name = "databindingService", service = { EMFFormsDatabinding.class, EMFFormsDatabindingEMF.class,
	EMFFormsSegmentResolver.class })
	public class EMFFormsDatabindingImpl implements EMFFormsDatabindingEMF, EMFFormsSegmentResolver {

	private static final RankingHelper<DomainModelReferenceConverterEMF> DMR_RANKING_HELPER = //
	new RankingHelper<DomainModelReferenceConverterEMF>(
	DomainModelReferenceConverter.class,
	DomainModelReferenceConverter.NOT_APPLICABLE,
	DomainModelReferenceConverter.NOT_APPLICABLE);

	private static final RankingHelper<DomainModelReferenceSegmentConverterEMF> SEGMENTS_RANKING_HELPER = //
	new RankingHelper<>(
	DomainModelReferenceSegmentConverterEMF.class,
	DomainModelReferenceSegmentConverterEMF.NOT_APPLICABLE,
	DomainModelReferenceSegmentConverterEMF.NOT_APPLICABLE);

	private final Set<DomainModelReferenceConverterEMF> referenceConverters = new LinkedHashSet<>();
	private final Set<DomainModelReferenceSegmentConverterEMF> segmentConverters = new LinkedHashSet<>();

	/**
	* Adds the given {@link DomainModelReferenceSegmentConverterEMF} to the Set of segment converters.
	*
	* @param converter The {@link DomainModelReferenceSegmentConverterEMF} to add
	*/
	@Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC)
	protected void addDomainModelReferenceSegmentConverter(DomainModelReferenceSegmentConverterEMF converter) {
	segmentConverters.add(converter);
	}

	/**
	* Removes the given {@link DomainModelReferenceSegmentConverterEMF} from the Set of segment converters.
	*
	* @param converter The {@link DomainModelReferenceSegmentConverterEMF} to remove
	*/
	protected void removeDomainModelReferenceSegmentConverter(DomainModelReferenceSegmentConverterEMF converter) {
	segmentConverters.remove(converter);
	}

	@Override
	public IObservableValue getObservableValue(VDomainModelReference domainModelReference, EObject object)
	throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();
	Assert.create(object).notNull();

	final IEMFValueProperty valueProperty = getValueProperty(domainModelReference, object);
	final Realm realm = Realm.getDefault();
	if (realm != null) {
	return valueProperty.observe(object);
	}
	final DefaultRealm dr = new DefaultRealm();
	final IObservableValue observableValue = valueProperty.observe(object);
	dr.dispose();
	return observableValue;
	}

	@Override
	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EObject object)
	throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();

	final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
	if (segments.isEmpty()) {
	// No segments => Fall back to legacy dmr resolving
	final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
	domainModelReference);
	return bestConverter.convertToValueProperty(domainModelReference, object);
	}

	Assert.create(object).notNull();
	final EditingDomain editingDomain = getEditingDomain(object);
	return internalGetValueProperty(domainModelReference, object.eClass(), editingDomain);
	}

	@Override
	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EClass rootEClass)
	throws DatabindingFailedException {
	return getValueProperty(domainModelReference, rootEClass, null);
	}

	@Override
	public IEMFValueProperty getValueProperty(VDomainModelReference domainModelReference, EClass rootEClass,
	EditingDomain editingDomain) throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();

	final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
	if (segments.isEmpty()) {
	// No segments => Fall back to legacy dmr resolving
	final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
	domainModelReference);
	return bestConverter.convertToValueProperty(domainModelReference, rootEClass, editingDomain);
	}

	Assert.create(rootEClass).notNull();
	return internalGetValueProperty(domainModelReference, rootEClass, editingDomain);
	}

	/**
	* Actual calculation of a value property using {@link VDomainModelReferenceSegment segments}.
	*
	* @param domainModelReference The domain model reference pointing to the desired value
	* @param rootEClass The root EClass of the rendered form
	* @param editingDomain The {@link EditingDomain} of the resulting value property, may be null
	* @return The resulting {@link IEMFValueProperty}
	* @throws DatabindingFailedException
	*/
	private IEMFValueProperty internalGetValueProperty(VDomainModelReference domainModelReference, EClass rootEClass,
	EditingDomain editingDomain) throws DatabindingFailedException {

	final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();

	// Get value property for the (always present) first segment
	final DomainModelReferenceSegmentConverterEMF firstConverter = getBestDomainModelReferenceSegmentConverter(
	segments.get(0));
	SegmentConverterValueResultEMF converterResult = firstConverter.convertToValueProperty(segments.get(0),
	rootEClass, editingDomain);
	IEMFValueProperty resultProperty = converterResult.getValueProperty();

	// Iterate over all remaining segments and get the value properties for their corresponding EClasses.
	for (int i = 1; i < segments.size(); i++) {
	final EClass nextEClass = unpackNextEClass(converterResult.getNextEClass(), domainModelReference,
	segments.get(i));
	final VDomainModelReferenceSegment segment = segments.get(i);

	final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
	segment);
	converterResult = bestConverter.convertToValueProperty(segment,
	nextEClass, editingDomain);
	final IEMFValueProperty nextProperty = converterResult.getValueProperty();
	// Chain the properties together
	resultProperty = resultProperty.value(nextProperty);
	}

	return resultProperty;
	}

	/**
	* Adds the given {@link DomainModelReferenceConverterEMF} to the Set of reference converters.
	*
	* @param converter The {@link DomainModelReferenceConverterEMF} to add
	*/
	@Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC)
	protected void addDomainModelReferenceConverter(DomainModelReferenceConverterEMF converter) {
	referenceConverters.add(converter);
	}

	/**
	* Removes the given {@link DomainModelReferenceConverterEMF} to the Set of reference converters.
	*
	* @param converter The {@link DomainModelReferenceConverterEMF} to remove
	*/
	protected void removeDomainModelReferenceConverter(DomainModelReferenceConverterEMF converter) {
	referenceConverters.remove(converter);
	}

	@Override
	public IObservableList getObservableList(VDomainModelReference domainModelReference, EObject object)
	throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();
	Assert.create(object).notNull();

	final IListProperty listProperty = getListProperty(domainModelReference, object);
	final Realm realm = Realm.getDefault();
	if (realm != null) {
	return listProperty.observe(object);
	}
	final DefaultRealm dr = new DefaultRealm();
	final IObservableList observableList = listProperty.observe(object);
	dr.dispose();
	return observableList;
	}

	@Override
	public IEMFListProperty getListProperty(VDomainModelReference domainModelReference, EObject object)
	throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();

	final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
	if (segments.isEmpty()) {
	// No segments => Fall back to legacy dmr resolving
	final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
	domainModelReference);
	return bestConverter.convertToListProperty(domainModelReference, object);
	}

	Assert.create(object).notNull();
	final EditingDomain editingDomain = getEditingDomain(object);

	// If there is only one segment, get its list property. Otherwise, get its value property
	final DomainModelReferenceSegmentConverterEMF firstConverter = getBestDomainModelReferenceSegmentConverter(
	segments.get(0));
	if (segments.size() == 1) {
	// If there is only one segment, directly return its list property
	return firstConverter.convertToListProperty(segments.get(0), object.eClass(), editingDomain)
	.getListProperty();
	}

	final SegmentConverterValueResultEMF converterResult = firstConverter.convertToValueProperty(segments.get(0),
	object.eClass(), editingDomain);
	IEMFValueProperty valueProperty = converterResult.getValueProperty();

	/*
	* Iterate over all "middle" segments and get the value properties for their corresponding EClasses.
	* Get the EClass by getting the target EClass of the EReference from the value property of the previously
	* resolved segment.
	*/
	EClass nextEClass = unpackNextEClass(converterResult.getNextEClass(), domainModelReference, segments.get(0));
	for (int i = 1; i < segments.size() - 1; i++) {
	final VDomainModelReferenceSegment segment = segments.get(i);

	final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
	segment);
	final SegmentConverterValueResultEMF nextConverterResult = bestConverter.convertToValueProperty(segment,
	nextEClass, editingDomain);
	final IEMFValueProperty nextProperty = nextConverterResult.getValueProperty();

	nextEClass = unpackNextEClass(nextConverterResult.getNextEClass(), domainModelReference, segment);
	// Chain the properties together
	valueProperty = valueProperty.value(nextProperty);
	}

	// Get the list property for the last segment
	final int lastIndex = segments.size() - 1;
	final DomainModelReferenceSegmentConverterEMF lastConverter = getBestDomainModelReferenceSegmentConverter(
	segments.get(lastIndex));
	final SegmentConverterListResultEMF converterListResult = lastConverter.convertToListProperty(
	segments.get(lastIndex), nextEClass,
	editingDomain);

	return valueProperty.list(converterListResult.getListProperty());
	}

	/**
	* Returns the most suitable {@link DomainModelReferenceConverter}, that is registered to this
	* {@link EMFFormsDatabindingImpl}, for the given {@link VDomainModelReference}.
	*
	* @param domainModelReference The {@link VDomainModelReference} for which a {@link DomainModelReferenceConverter}
	* is needed
	* @return The most suitable {@link DomainModelReferenceConverter}
	* @throws DatabindingFailedException If no applicable DMR Converter was found
	*/
	private DomainModelReferenceConverterEMF getBestDomainModelReferenceConverter(
	final VDomainModelReference domainModelReference) throws DatabindingFailedException {
	if (domainModelReference == null) {
	throw new IllegalArgumentException("The given VDomainModelReference must not be null."); //$NON-NLS-1$
	}

	final DomainModelReferenceConverterEMF bestConverter = DMR_RANKING_HELPER.getHighestRankingElement(
	referenceConverters, converter -> converter.isApplicable(domainModelReference));
	if (bestConverter == null) {
	throw new DatabindingFailedException("No applicable DomainModelReferenceConverter could be found."); //$NON-NLS-1$
	}
	return bestConverter;
	}

	@Override
	public EStructuralFeature extractFeature(IObservableValue observableValue) throws DatabindingFailedException {
	if (IEMFObservable.class.isInstance(observableValue)) {
	return IEMFObservable.class.cast(observableValue).getStructuralFeature();
	}
	throw new DatabindingFailedException(
	String.format("The IObservableValue class %1$s is not supported!", observableValue.getClass().getName())); //$NON-NLS-1$
	}

	@Override
	public EStructuralFeature extractFeature(IObservableList observableList) throws DatabindingFailedException {
	if (IEMFObservable.class.isInstance(observableList)) {
	return IEMFObservable.class.cast(observableList).getStructuralFeature();
	}
	throw new DatabindingFailedException(
	String.format("The IObservableList class %1$s is not supported!", observableList.getClass().getName())); //$NON-NLS-1$
	}

	@Override
	public EObject extractObserved(IObservableValue observableValue) throws DatabindingFailedException {
	if (IEMFObservable.class.isInstance(observableValue)) {
	return (EObject) IEMFObservable.class.cast(observableValue).getObserved();
	}
	throw new DatabindingFailedException(
	String.format("The IObservableValue class %1$s is not supported!", observableValue.getClass().getName())); //$NON-NLS-1$
	}

	@Override
	public EObject extractObserved(IObservableList observableList) throws DatabindingFailedException {
	if (IEMFObservable.class.isInstance(observableList)) {
	return (EObject) IEMFObservable.class.cast(observableList).getObserved();
	}
	throw new DatabindingFailedException(
	String.format("The IObservableList class %1$s is not supported!", observableList.getClass().getName())); //$NON-NLS-1$
	}

	@Override
	public Setting getSetting(VDomainModelReference domainModelReference, EObject object)
	throws DatabindingFailedException {
	Assert.create(domainModelReference).notNull();
	Assert.create(object).notNull();

	final EList<VDomainModelReferenceSegment> segments = domainModelReference.getSegments();
	if (segments.isEmpty()) {
	// No segments => Fall back to legacy dmr resolving
	final DomainModelReferenceConverterEMF bestConverter = getBestDomainModelReferenceConverter(
	domainModelReference);
	final Realm realm = Realm.getDefault();
	if (realm != null) {
	return bestConverter.getSetting(domainModelReference, object);
	}
	final DefaultRealm dr = new DefaultRealm();
	final Setting setting = bestConverter.getSetting(domainModelReference, object);
	dr.dispose();
	return setting;
	}

	Setting setting = resolveSegment(segments.get(0), object);

	/*
	* If present, iterate over the remaining segments. For every iteration step, use the resolved EObject of the
	* previously resolved Setting in order to resolve the next Setting.
	*/
	for (int i = 1; i < segments.size(); i++) {
	final VDomainModelReferenceSegment segment = segments.get(i);
	final Object nextObject = setting.get(true);

	if (!EObject.class.isInstance(nextObject)) {
	throw new DatabindingFailedException(
	String.format(
	"The Setting could not be fully resolved because an intermediate Object was no EObject or was null. " //$NON-NLS-1$
	+ "The DMR was %1$s. The last resolved segment was %2$s. The root EObject was %3$s.", //$NON-NLS-1$
	domainModelReference, segments.get(i - 1), object));
	}

	final EObject nextEObject = (EObject) nextObject;
	setting = resolveSegment(segment, nextEObject);
	}

	return setting;
	}

	/**
	* Returns the most suitable {@link DomainModelReferenceSegmentConverterEMF}, that is registered to this
	* {@link EMFFormsDatabindingImpl}, for the given {@link VDomainModelReferenceSegment}.
	*
	* @param segment The {@link VDomainModelReferenceSegment} for which a
	* {@link DomainModelReferenceSegmentConverterEMF}
	* is needed
	* @return The most suitable {@link DomainModelReferenceSegmentConverterEMF}, does not return <code>null</code>
	* @throws DatabindingFailedException if no suitable segment converter could be found
	*/
	private DomainModelReferenceSegmentConverterEMF getBestDomainModelReferenceSegmentConverter(
	final VDomainModelReferenceSegment segment) throws DatabindingFailedException {

	final DomainModelReferenceSegmentConverterEMF bestConverter = SEGMENTS_RANKING_HELPER.getHighestRankingElement(
	segmentConverters, converter -> converter.isApplicable(segment));

	if (bestConverter == null) {
	throw new DatabindingFailedException(String
	.format("No suitable DomainModelReferenceSegmentConverter could be found for segment %1$s", segment)); //$NON-NLS-1$
	}
	return bestConverter;

	}

	/**
	* Unpacks the given {@link EClass} Optional and throws an exception if it is not present.
	*
	* @param nextEClass the {@link EClass} to check
	* @param domainModelReference only needed for exception description
	* @param segment only needed for exception description
	* @return the unpacked {@link EClass}
	* @throws DatabindingFailedException if the next EClass is <code>null</code>
	*/
	private EClass unpackNextEClass(final Optional<EClass> nextEClass, VDomainModelReference domainModelReference,
	final VDomainModelReferenceSegment segment) throws DatabindingFailedException {
	return nextEClass.orElseThrow(() -> new DatabindingFailedException(String.format(
	"The Segment [%1$s] could not be resolved because this segment's root EClass" //$NON-NLS-1$
	+ " could not be resolved from the preceding segment. The DMR is %2$s.", //$NON-NLS-1$
	segment, domainModelReference)));
	}

	private EditingDomain getEditingDomain(EObject object) throws DatabindingFailedException {
	return AdapterFactoryEditingDomain.getEditingDomainFor(object);
	}

	@Override
	public Setting resolveSegment(VDomainModelReferenceSegment segment, EObject domainObject)
	throws DatabindingFailedException {
	final DomainModelReferenceSegmentConverterEMF bestConverter = getBestDomainModelReferenceSegmentConverter(
	segment);
	return bestConverter.getSetting(segment, domainObject);
	}
	}