bundles/org.eclipse.emfforms.core.bazaar/src/org/eclipse/emfforms/bazaar/internal/BazaarImpl.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:
  * jonas - initial API and implementation
  ******************************************************************************/
 package org.eclipse.emfforms.bazaar.internal;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.PriorityQueue;
 import java.util.Queue;
 import java.util.Set;

 import org.eclipse.e4.core.contexts.ContextInjectionFactory;
 import org.eclipse.e4.core.contexts.EclipseContextFactory;
 import org.eclipse.e4.core.contexts.IContextFunction;
 import org.eclipse.e4.core.contexts.IEclipseContext;
 import org.eclipse.e4.core.di.InjectionException;
 import org.eclipse.emfforms.bazaar.Bazaar;
 import org.eclipse.emfforms.bazaar.BazaarContext;
 import org.eclipse.emfforms.bazaar.BazaarContextFunction;
 import org.eclipse.emfforms.bazaar.Bid;
 import org.eclipse.emfforms.bazaar.Create;
 import org.eclipse.emfforms.bazaar.Exchange;
 import org.eclipse.emfforms.bazaar.Precondition;
 import org.eclipse.emfforms.bazaar.Preconditions;
 import org.eclipse.emfforms.bazaar.StaticBid;
 import org.eclipse.emfforms.bazaar.Vendor;

 /**
  * Implementation of a {@link Bazaar} using the {@link IEclipseContext} for dependency injection.
  *
  * @param <T> the type of product produced by this {@link Bazaar}
  * @author jonas
  *
  */
 public class BazaarImpl<T> implements Bazaar<T> {

 	private final Set<Vendor<? extends T>> vendors = new LinkedHashSet<Vendor<? extends T>>();

 	private PriorityOverlapCallBack<? super T> priorityOverlapCallBack;

 	private final Map<String, BazaarContextFunction> contextFunctionMap = new HashMap<String, BazaarContextFunction>();

 	@Override
 	public void addVendor(Vendor<? extends T> vendor) {
 		vendors.add(vendor);
 	}

 	@Override
 	public void removeVendor(Vendor<? extends T> vendor) {
 		vendors.remove(vendor);
 	}

 	/**
 	 * Returns the product which is provided with the highest priority by any {@link Vendor}.
 	 *
 	 * @param vendor The {@link Vendor} creating the product
 	 * @param context The {@link IEclipseContext} to inject parameters for creating a product (see {@link Create})
 	 * @return T the created product
 	 */
 	@SuppressWarnings("unchecked")
 	public T createProduct(Vendor<? extends T> vendor, IEclipseContext context) {
 		try {
 			return (T) ContextInjectionFactory.invoke(vendor, Create.class, context);
 		} catch (final InjectionException e) {
 			return null;
 		}
 	}

 	/**
 	 * Transforms all {@link BazaarContextFunction}s to {@link IContextFunction}s and attaches those to an
 	 * {@link IEclipseContext}.
 	 *
 	 * @param context the {@link IEclipseContext} to attache {@link IContextFunction}s to
 	 * @return the {@link IEclipseContext} with attached {@link IContextFunction}
 	 */
 	public IEclipseContext addContextFunctions(IEclipseContext context) {
 		final Set<Entry<String, BazaarContextFunction>> entrySet = contextFunctionMap.entrySet();
 		for (final Entry<String, BazaarContextFunction> entry : entrySet) {
 			final IContextFunction iContextFunction = new IContextFunction() {

 				@Override
 				public Object compute(IEclipseContext context, String contextKey) {
 					try {
 						final Object transformed = ContextInjectionFactory.invoke(entry.getValue(), Exchange.class,
 							context);
 						if (transformed != null) {
 							context.set(entry.getKey(), transformed);
 						}
 						return transformed;
 					} catch (final InjectionException e) {
 						return null;
 					}
 				}
 			};
 			context.set(entry.getKey(), iContextFunction);
 		}
 		return context;
 	}

 	/**
 	 * Creates an {@link IEclipseContext} from a {@link BazaarContext}.
 	 *
 	 * @param bazaarContext the {@link BazaarContext} to get key / values from
 	 * @return a {@link IEclipseContext} containign all key / values provided by the {@link BazaarContext}
 	 */
 	public IEclipseContext createEclipseContext(BazaarContext bazaarContext) {
 		final IEclipseContext context = EclipseContextFactory.create();
 		final Set<String> keySet = bazaarContext.getContextMap().keySet();
 		for (final String string : keySet) {
 			context.set(string, bazaarContext.getContextMap().get(string));
 		}
 		return context;
 	}

 	/**
 	 * @param context the Eclipse injection context
 	 * @return obtains the best available vendor for the give {@code context}
 	 */
 	public Vendor<? extends T> getBestVendor(IEclipseContext context) {
 		Double winningBid = null;
 		Vendor<? extends T> winner = null;

 		for (final Vendor<? extends T> vendor : vendors) {
 			final Double bid = bid(vendor, context);

 			if (bid == null) {
 				// This vendor refuses to bid
 				continue;
 			}

 			if (winningBid == null || bid > winningBid) {
 				// We have a new winner
 				winningBid = bid;
 				winner = vendor;
 			} else if (bid.equals(winningBid)) {
 				// Report the tie and keep the current winner
 				reportPriorityOverlap(winner, vendor);
 			}
 		}

 		return winner;
 	}

 	private Double bid(Vendor<? extends T> vendor, IEclipseContext context) {
 		if (!checkPreConditions(vendor, context)) {
 			return null;
 		}

 		Double result = null; // Assume no bid

 		result = staticBid(vendor);
 		if (result != null) {
 			return result;
 		}

 		try {
 			result = (Double) ContextInjectionFactory.invoke(vendor, Bid.class, context);
 		} catch (final InjectionException e) {
 			// Do nothing. The vendor refuses the bid
 		} catch (final ClassCastException e) {
 			// Bid method did not return a double. Reject it
 		}

 		return result;
 	}

 	private Double staticBid(Vendor<? extends T> vendor) {
 		final StaticBid staticBid = vendor.getClass().getAnnotation(StaticBid.class);
 		if (staticBid != null) {
 			return staticBid.bid();
 		}
 		return null;
 	}

 	private Queue<Vendor<? extends T>> createVendorPriorityQueue(IEclipseContext context) {
 		final Map<Vendor<? extends T>, Double> priorities = new HashMap<Vendor<? extends T>, Double>();
 		for (final Vendor<? extends T> vendor : vendors) {
 			final Double bid = bid(vendor, context);

 			if (bid != null) {
 				priorities.put(vendor, bid);
 			} // else the vendor refuses to bid
 		}

 		if (priorities.isEmpty()) {
 			return new PriorityQueue<Vendor<? extends T>>();
 		}

 		final Comparator<Vendor<? extends T>> ordering = new Comparator<Vendor<? extends T>>() {
 			@Override
 			public int compare(Vendor<? extends T> o1, Vendor<? extends T> o2) {
 				// Sort highest bid to lowest
 				return priorities.get(o2).compareTo(priorities.get(o1));
 			}
 		};

 		final PriorityQueue<Vendor<? extends T>> result = new PriorityQueue<Vendor<? extends T>>(priorities.size(),
 			ordering);
 		result.addAll(priorities.keySet());

 		return result;
 	}

 	/**
 	 * @param existingVendorWithSamePriority
 	 * @param vendor
 	 */
 	private void reportPriorityOverlap(Vendor<? extends T> existingVendorWithSamePriority, Vendor<? extends T> vendor) {
 		if (priorityOverlapCallBack == null) {
 			return;
 		}
 		priorityOverlapCallBack.priorityOverlap(existingVendorWithSamePriority, vendor);

 	}

 	@Override
 	public void setPriorityOverlapCallBack(PriorityOverlapCallBack<? super T> priorityOverlapCallBack) {
 		this.priorityOverlapCallBack = priorityOverlapCallBack;
 	}

 	/**
 	 * @param key
 	 * @param contextFunction
 	 */
 	@Override
 	public void addContextFunction(String key, BazaarContextFunction contextFunction) {
 		contextFunctionMap.put(key, contextFunction);
 	}

 	/**
 	 *
 	 * @see org.eclipse.emfforms.bazaar.Bazaar#createProduct(org.eclipse.emfforms.bazaar.BazaarContext)
 	 */
 	@Override
 	public T createProduct(BazaarContext bazaarContext) {
 		final IEclipseContext eclipseContext = createEclipseContextWithFunctions(bazaarContext);
 		final Vendor<? extends T> bestVendor = getBestVendor(eclipseContext);
 		if (bestVendor == null) {
 			return null;
 		}
 		final T createProduct = createProduct(bestVendor, eclipseContext);
 		return createProduct;
 	}

 	private IEclipseContext createEclipseContextWithFunctions(BazaarContext bazaarContext) {
 		IEclipseContext eclipseContext = createEclipseContext(bazaarContext);
 		eclipseContext = addContextFunctions(eclipseContext);
 		return eclipseContext;
 	}

 	/**
 	 *
 	 * @see org.eclipse.emfforms.bazaar.Bazaar#createProducts(org.eclipse.emfforms.bazaar.BazaarContext)
 	 */
 	@Override
 	public List<T> createProducts(BazaarContext bazaarContext) {
 		final IEclipseContext eclipseContext = createEclipseContextWithFunctions(bazaarContext);
 		final Queue<Vendor<? extends T>> vendorQueue = createVendorPriorityQueue(eclipseContext);
 		if (vendorQueue.isEmpty()) {
 			return Collections.emptyList();
 		}

 		final List<T> ret = new ArrayList<T>();
 		for (Vendor<? extends T> vendor = vendorQueue.poll(); vendor != null; vendor = vendorQueue.poll()) {
 			final T createProduct = createProduct(vendor, eclipseContext);
 			if (createProduct != null) {
 				ret.add(createProduct);
 			}
 		}

 		return ret;
 	}

 	/**
 	 * Checks the {@link Precondition}s for a given vendor.
 	 *
 	 * @param vendor The {@link Vendor} to check the {@link Precondition} for.
 	 * @param context The {@link IEclipseContext} to provide the {@link Precondition}
 	 * @return whether the {@link Precondition}s are fulfilled
 	 */
 	public boolean checkPreConditions(Vendor<? extends T> vendor, IEclipseContext context) {
 		final Set<Precondition> preConditionList = new LinkedHashSet<Precondition>();
 		final Precondition preConditionAnnotation = vendor.getClass().getAnnotation(Precondition.class);
 		if (preConditionAnnotation != null) {
 			preConditionList.add(preConditionAnnotation);
 		}
 		final Preconditions conditions = vendor.getClass().getAnnotation(Preconditions.class);
 		if (conditions != null) {
 			preConditionList.addAll(Arrays.asList(conditions.preconditions()));
 		}
 		for (final Precondition preCondition : preConditionList) {
 			if (!checkPreCondition(preCondition, vendor, context)) {
 				return false;
 			}
 		}
 		return true;
 	}

 	private boolean checkPreCondition(Precondition preCondition, Vendor<? extends T> vendor, IEclipseContext context) {
 		if (preCondition.value().equals(Precondition.UNASSIGNED)) {
 			return context.containsKey(preCondition.key());
 		}
 		final Object object = context.get(preCondition.key());
 		if (object == null) {
 			return false;
 		}
 		return object.equals(preCondition.value());
 	}

 }
	/*******************************************************************************
	* 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:
	* jonas - initial API and implementation
	******************************************************************************/
	package org.eclipse.emfforms.bazaar.internal;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.HashMap;
	import java.util.LinkedHashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Map.Entry;
	import java.util.PriorityQueue;
	import java.util.Queue;
	import java.util.Set;

	import org.eclipse.e4.core.contexts.ContextInjectionFactory;
	import org.eclipse.e4.core.contexts.EclipseContextFactory;
	import org.eclipse.e4.core.contexts.IContextFunction;
	import org.eclipse.e4.core.contexts.IEclipseContext;
	import org.eclipse.e4.core.di.InjectionException;
	import org.eclipse.emfforms.bazaar.Bazaar;
	import org.eclipse.emfforms.bazaar.BazaarContext;
	import org.eclipse.emfforms.bazaar.BazaarContextFunction;
	import org.eclipse.emfforms.bazaar.Bid;
	import org.eclipse.emfforms.bazaar.Create;
	import org.eclipse.emfforms.bazaar.Exchange;
	import org.eclipse.emfforms.bazaar.Precondition;
	import org.eclipse.emfforms.bazaar.Preconditions;
	import org.eclipse.emfforms.bazaar.StaticBid;
	import org.eclipse.emfforms.bazaar.Vendor;

	/**
	* Implementation of a {@link Bazaar} using the {@link IEclipseContext} for dependency injection.
	*
	* @param <T> the type of product produced by this {@link Bazaar}
	* @author jonas
	*
	*/
	public class BazaarImpl<T> implements Bazaar<T> {

	private final Set<Vendor<? extends T>> vendors = new LinkedHashSet<Vendor<? extends T>>();

	private PriorityOverlapCallBack<? super T> priorityOverlapCallBack;

	private final Map<String, BazaarContextFunction> contextFunctionMap = new HashMap<String, BazaarContextFunction>();

	@Override
	public void addVendor(Vendor<? extends T> vendor) {
	vendors.add(vendor);
	}

	@Override
	public void removeVendor(Vendor<? extends T> vendor) {
	vendors.remove(vendor);
	}

	/**
	* Returns the product which is provided with the highest priority by any {@link Vendor}.
	*
	* @param vendor The {@link Vendor} creating the product
	* @param context The {@link IEclipseContext} to inject parameters for creating a product (see {@link Create})
	* @return T the created product
	*/
	@SuppressWarnings("unchecked")
	public T createProduct(Vendor<? extends T> vendor, IEclipseContext context) {
	try {
	return (T) ContextInjectionFactory.invoke(vendor, Create.class, context);
	} catch (final InjectionException e) {
	return null;
	}
	}

	/**
	* Transforms all {@link BazaarContextFunction}s to {@link IContextFunction}s and attaches those to an
	* {@link IEclipseContext}.
	*
	* @param context the {@link IEclipseContext} to attache {@link IContextFunction}s to
	* @return the {@link IEclipseContext} with attached {@link IContextFunction}
	*/
	public IEclipseContext addContextFunctions(IEclipseContext context) {
	final Set<Entry<String, BazaarContextFunction>> entrySet = contextFunctionMap.entrySet();
	for (final Entry<String, BazaarContextFunction> entry : entrySet) {
	final IContextFunction iContextFunction = new IContextFunction() {

	@Override
	public Object compute(IEclipseContext context, String contextKey) {
	try {
	final Object transformed = ContextInjectionFactory.invoke(entry.getValue(), Exchange.class,
	context);
	if (transformed != null) {
	context.set(entry.getKey(), transformed);
	}
	return transformed;
	} catch (final InjectionException e) {
	return null;
	}
	}
	};
	context.set(entry.getKey(), iContextFunction);
	}
	return context;
	}

	/**
	* Creates an {@link IEclipseContext} from a {@link BazaarContext}.
	*
	* @param bazaarContext the {@link BazaarContext} to get key / values from
	* @return a {@link IEclipseContext} containign all key / values provided by the {@link BazaarContext}
	*/
	public IEclipseContext createEclipseContext(BazaarContext bazaarContext) {
	final IEclipseContext context = EclipseContextFactory.create();
	final Set<String> keySet = bazaarContext.getContextMap().keySet();
	for (final String string : keySet) {
	context.set(string, bazaarContext.getContextMap().get(string));
	}
	return context;
	}

	/**
	* @param context the Eclipse injection context
	* @return obtains the best available vendor for the give {@code context}
	*/
	public Vendor<? extends T> getBestVendor(IEclipseContext context) {
	Double winningBid = null;
	Vendor<? extends T> winner = null;

	for (final Vendor<? extends T> vendor : vendors) {
	final Double bid = bid(vendor, context);

	if (bid == null) {
	// This vendor refuses to bid
	continue;
	}

	if (winningBid == null \|\| bid > winningBid) {
	// We have a new winner
	winningBid = bid;
	winner = vendor;
	} else if (bid.equals(winningBid)) {
	// Report the tie and keep the current winner
	reportPriorityOverlap(winner, vendor);
	}
	}

	return winner;
	}

	private Double bid(Vendor<? extends T> vendor, IEclipseContext context) {
	if (!checkPreConditions(vendor, context)) {
	return null;
	}

	Double result = null; // Assume no bid

	result = staticBid(vendor);
	if (result != null) {
	return result;
	}

	try {
	result = (Double) ContextInjectionFactory.invoke(vendor, Bid.class, context);
	} catch (final InjectionException e) {
	// Do nothing. The vendor refuses the bid
	} catch (final ClassCastException e) {
	// Bid method did not return a double. Reject it
	}

	return result;
	}

	private Double staticBid(Vendor<? extends T> vendor) {
	final StaticBid staticBid = vendor.getClass().getAnnotation(StaticBid.class);
	if (staticBid != null) {
	return staticBid.bid();
	}
	return null;
	}

	private Queue<Vendor<? extends T>> createVendorPriorityQueue(IEclipseContext context) {
	final Map<Vendor<? extends T>, Double> priorities = new HashMap<Vendor<? extends T>, Double>();
	for (final Vendor<? extends T> vendor : vendors) {
	final Double bid = bid(vendor, context);

	if (bid != null) {
	priorities.put(vendor, bid);
	} // else the vendor refuses to bid
	}

	if (priorities.isEmpty()) {
	return new PriorityQueue<Vendor<? extends T>>();
	}

	final Comparator<Vendor<? extends T>> ordering = new Comparator<Vendor<? extends T>>() {
	@Override
	public int compare(Vendor<? extends T> o1, Vendor<? extends T> o2) {
	// Sort highest bid to lowest
	return priorities.get(o2).compareTo(priorities.get(o1));
	}
	};

	final PriorityQueue<Vendor<? extends T>> result = new PriorityQueue<Vendor<? extends T>>(priorities.size(),
	ordering);
	result.addAll(priorities.keySet());

	return result;
	}

	/**
	* @param existingVendorWithSamePriority
	* @param vendor
	*/
	private void reportPriorityOverlap(Vendor<? extends T> existingVendorWithSamePriority, Vendor<? extends T> vendor) {
	if (priorityOverlapCallBack == null) {
	return;
	}
	priorityOverlapCallBack.priorityOverlap(existingVendorWithSamePriority, vendor);

	}

	@Override
	public void setPriorityOverlapCallBack(PriorityOverlapCallBack<? super T> priorityOverlapCallBack) {
	this.priorityOverlapCallBack = priorityOverlapCallBack;
	}

	/**
	* @param key
	* @param contextFunction
	*/
	@Override
	public void addContextFunction(String key, BazaarContextFunction contextFunction) {
	contextFunctionMap.put(key, contextFunction);
	}

	/**
	*
	* @see org.eclipse.emfforms.bazaar.Bazaar#createProduct(org.eclipse.emfforms.bazaar.BazaarContext)
	*/
	@Override
	public T createProduct(BazaarContext bazaarContext) {
	final IEclipseContext eclipseContext = createEclipseContextWithFunctions(bazaarContext);
	final Vendor<? extends T> bestVendor = getBestVendor(eclipseContext);
	if (bestVendor == null) {
	return null;
	}
	final T createProduct = createProduct(bestVendor, eclipseContext);
	return createProduct;
	}

	private IEclipseContext createEclipseContextWithFunctions(BazaarContext bazaarContext) {
	IEclipseContext eclipseContext = createEclipseContext(bazaarContext);
	eclipseContext = addContextFunctions(eclipseContext);
	return eclipseContext;
	}

	/**
	*
	* @see org.eclipse.emfforms.bazaar.Bazaar#createProducts(org.eclipse.emfforms.bazaar.BazaarContext)
	*/
	@Override
	public List<T> createProducts(BazaarContext bazaarContext) {
	final IEclipseContext eclipseContext = createEclipseContextWithFunctions(bazaarContext);
	final Queue<Vendor<? extends T>> vendorQueue = createVendorPriorityQueue(eclipseContext);
	if (vendorQueue.isEmpty()) {
	return Collections.emptyList();
	}

	final List<T> ret = new ArrayList<T>();
	for (Vendor<? extends T> vendor = vendorQueue.poll(); vendor != null; vendor = vendorQueue.poll()) {
	final T createProduct = createProduct(vendor, eclipseContext);
	if (createProduct != null) {
	ret.add(createProduct);
	}
	}

	return ret;
	}

	/**
	* Checks the {@link Precondition}s for a given vendor.
	*
	* @param vendor The {@link Vendor} to check the {@link Precondition} for.
	* @param context The {@link IEclipseContext} to provide the {@link Precondition}
	* @return whether the {@link Precondition}s are fulfilled
	*/
	public boolean checkPreConditions(Vendor<? extends T> vendor, IEclipseContext context) {
	final Set<Precondition> preConditionList = new LinkedHashSet<Precondition>();
	final Precondition preConditionAnnotation = vendor.getClass().getAnnotation(Precondition.class);
	if (preConditionAnnotation != null) {
	preConditionList.add(preConditionAnnotation);
	}
	final Preconditions conditions = vendor.getClass().getAnnotation(Preconditions.class);
	if (conditions != null) {
	preConditionList.addAll(Arrays.asList(conditions.preconditions()));
	}
	for (final Precondition preCondition : preConditionList) {
	if (!checkPreCondition(preCondition, vendor, context)) {
	return false;
	}
	}
	return true;
	}

	private boolean checkPreCondition(Precondition preCondition, Vendor<? extends T> vendor, IEclipseContext context) {
	if (preCondition.value().equals(Precondition.UNASSIGNED)) {
	return context.containsKey(preCondition.key());
	}
	final Object object = context.get(preCondition.key());
	if (object == null) {
	return false;
	}
	return object.equals(preCondition.value());
	}

	}