org.eclipse.osbp.runtime.common/src/org/eclipse/osbp/runtime/common/state/SharedStateUnitOfWork.java

/**
 * Copyright (c) 2011, 2015 - Lunifera GmbH (Gross Enzersdorf, Austria), 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:
 *         Florian Pirchner - Initial implementation
 */
package org.eclipse.osbp.runtime.common.state;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.osbp.runtime.common.coordination.CoordinationManager;
import org.osgi.service.coordinator.Coordination;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// TODO: Auto-generated Javadoc
/**
 * The Class SharedStateUnitOfWork.
 *
 * @param <R>
 *            the generic type
 */
public abstract class SharedStateUnitOfWork<R> {
	
	/** The Constant LOGGER. */
	private static final Logger LOGGER = LoggerFactory
			.getLogger(SharedStateUnitOfWork.class);

	/**
	 * Instantiates a new shared state unit of work.
	 */
	public SharedStateUnitOfWork() {

	}

	/**
	 * Executes the unit of work creating an implicit {@link Coordination} and
	 * passing the env as variables.
	 *
	 * @param context
	 *            the context
	 * @return the data returned by {@link #doExecute()}
	 */
	public R execute(final ISharedStateContext context) {
		if (context != null) {
			Coordination peek = null;
			CoordinationManager coordinationManager = new CoordinationManager();
			try {
				Map<Class<?>, Object> props = new HashMap<Class<?>, Object>();
				props.put(ISharedStateContext.class, context);
				peek = coordinationManager.createCurrentCoordination(props);
				if (peek != null) {
					return doExecute();
				} else {
					LOGGER.error("No coordination service available!");
				}
			} finally {
				if (peek != null) {
					peek.end();
				}
				// release the coordination manager
				coordinationManager.release();
			}
		} else {
			return doExecute();
		}
		return null;
	}

	/**
	 * The unit of work to do.
	 * 
	 * @return any kind of data. May also be <code>null</code>.
	 */
	protected abstract R doExecute();

}