org.eclipse.osbp.infogrid.services/src/org/eclipse/osbp/infogrid/services/GridSourceFacadeImpl.java

/**
 *                                                                            
 * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 *                                                                            
 * 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:   
 * Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation 
 */
 package org.eclipse.osbp.infogrid.services;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.osbp.infogrid.api.IGridSourceCache;
import org.eclipse.osbp.infogrid.api.IGridSourceDescriptor;
import org.eclipse.osbp.infogrid.api.IGridSourceDescriptor.ConfigCallback;
import org.eclipse.osbp.infogrid.api.IGridSourceDescriptorProvider;
import org.eclipse.osbp.infogrid.api.IGridSourceFacade;
import org.eclipse.osbp.infogrid.model.gridsource.CxGridSource;
import org.osgi.framework.ServiceReference;
import org.osgi.service.component.ComponentContext;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;

@Component(immediate = true)
public class GridSourceFacadeImpl implements IGridSourceFacade {

	private ComponentContext context;
	private List<ServiceReference<IGridSourceDescriptorProvider>> descriptorFactories = new ArrayList<>();

	private IGridSourceCache cache;

	@Activate
	protected void activate(ComponentContext context) {
		this.context = context;
	}

	@Deactivate
	protected void deactivate(ComponentContext context) {
		this.context = null;
	}

	@Override
	public CxGridSource getSource(String id) {
		CxGridSource source = cache.getSource(id);
		return source != null ? EcoreUtil.copy(source) : null;
	}

	@Override
	public List<CxGridSource> getSources(Class<?> inputType) {
		List<CxGridSource> sources = cache.getSources(inputType);
		if (sources == null) {
			return Collections.emptyList();
		}

		List<CxGridSource> copies = new ArrayList<CxGridSource>(sources.size());
		for (CxGridSource source : sources) {
			copies.add(EcoreUtil.copy(source));
		}

		return copies;
	}

	@Override
	public IGridSourceDescriptor getDescriptor(Class<?> inputType, String sourceId,
			IGridSourceDescriptor.ConfigCallback callback) {
		CxGridSource cxSource = getSource(sourceId);
		if (cxSource == null) {
			return null;
		}

		return getDescriptor(inputType, cxSource, null);
	}

	public IGridSourceDescriptor getDescriptor(Class<?> inputType,
			CxGridSource cxSource, IGridSourceDescriptor.ConfigCallback callback) {
		List<ServiceReference<IGridSourceDescriptorProvider>> temp = new ArrayList<>(
				descriptorFactories);

		// try to find a descriptor provider that handles the gridSourceId
		// directly
		for (ServiceReference<IGridSourceDescriptorProvider> ref : temp) {
			String prop = (String) ref
					.getProperty(IGridSourceDescriptorProvider.PROP_KIND);
			if (prop != null && prop.equals(cxSource.getId())) {
				return createDescriptor(ref, inputType, cxSource, callback);
			}
		}

		// try to find a descriptor provider that handles the type
		for (ServiceReference<IGridSourceDescriptorProvider> ref : temp) {
			String prop = (String) ref
					.getProperty(IGridSourceDescriptorProvider.PROP_KIND);
			if (prop != null && prop.equals(cxSource.getKind())) {
				return createDescriptor(ref, inputType, cxSource, callback);
			}
		}

		return null;
	}

	private IGridSourceDescriptor createDescriptor(
			ServiceReference<IGridSourceDescriptorProvider> ref,
			Class<?> inputType, CxGridSource cxSource, IGridSourceDescriptor.ConfigCallback callback) {
		IGridSourceDescriptorProvider provider = context.getBundleContext()
				.getService(ref);
		return provider.createDescriptor(inputType, cxSource, callback);
	}

	@Override
	public List<IGridSourceDescriptor> getDescriptors(Class<?> inputType,
			IGridSourceDescriptor.ConfigCallback callback) {
		List<CxGridSource> sources = getSources(inputType);
		if (sources.isEmpty()) {
			return Collections.emptyList();
		}

		List<IGridSourceDescriptor> result = new ArrayList<>(sources.size());
		for (CxGridSource source : sources) {
			IGridSourceDescriptor descriptor = getDescriptor(inputType, source,
					callback);
			if (descriptor != null) {
				result.add(descriptor);
			}
		}

		return result;
	}

	@Reference(service = IGridSourceDescriptorProvider.class, cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC, unbind = "removeDescriptorProvider")
	protected void addDescriptorProvider(
			ServiceReference<IGridSourceDescriptorProvider> ref) {
		descriptorFactories.add(ref);
	}

	protected void removeDescriptorProvider(
			ServiceReference<IGridSourceDescriptorProvider> ref) {
		descriptorFactories.remove(ref);
	}

	@Reference(cardinality = ReferenceCardinality.MANDATORY, policy = ReferencePolicy.STATIC, unbind = "unbindGridSourceCache")
	protected void bindGridSourceCache(IGridSourceCache cache) {
		this.cache = cache;
	}

	protected void unbindGridSourceCache(IGridSourceCache cache) {
		this.cache = null;
	}

}