/*******************************************************************************
 * Copyright 2017 Graz University of Technology
 * EAAF-Core Components has been developed in a cooperation between EGIZ,  
 * A-SIT+, A-SIT, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
package at.gv.egiz.eaaf.core.api.idp.process;

import java.io.Serializable;
import java.util.Set;

/**
 * Encapsulates data needed for or provided by task execution.
 * 
 * @author tknall
 * 
 */
public interface ExecutionContext extends Serializable {

	/**
	 * Returns the identifier of underlying process instance.
	 * 
	 * @return The identifier of the process instance.
	 */
	String getProcessInstanceId();

	/**
	 * Sets the identifier of underlying process instance.
	 * 
	 * @param processInstanceId
	 *            The identifier of the process instance.
	 */
	void setProcessInstanceId(String processInstanceId);

	/**
	 * Stores a serializable object using {@code key}.
	 * 
	 * @param key
	 *            The key under that the {@code object} should be stored.
	 * @param object The object to be stored.
	 */
	void put(String key, Serializable object);

	/**
	 * Returns an serializable object stored within this process context using {@code key}.
	 * 
	 * @param key
	 *            The key that has been used to store the serializable object (may be {@code null}).
	 * @return The object or {@code null} in case the key does not relate to a stored object or the stored object itself
	 *         was {@code null}.
	 */
	Serializable get(String key);
	
	/**
	 * Removes the object stored using {@code key}.
	 * @param key
	 *            The key that has been used to store the serializable object (may be {@code null}).
	 * @return The object that has been removed or {@code null} there was no object stored using {@code key}.
	 */
	Serializable remove(String key);

	/**
	 * Returns an unmodifiable set containing the stored keys.
	 * 
	 * @return The keyset (never {@code null}).
	 */
	Set<String> keySet();

}