/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.ode.bpel.iapi;

import javax.xml.namespace.QName;

/**
 * Interface exposing the BPEL "engine". Basically, this interface facilitates
 * dropping off events for processing by the engine. It is expected that
 * <em>all</em> of the methods of this interface are called only from a
 * "transactional context" (i.e. a transaction is associated with the thread
 * invoking the method). The exact nature of the transactional context is not
 * specified, however it must be the same context that is used by the BPEL DAO
 * layer implementation. If a method invoked from this interface throws an
 * exception of any kind, then the current transaction <em>must</em> be rolled
 * back.
 */
public interface BpelEngine extends Scheduler.JobProcessor {

    /**
     * Create a "my role" message exchange for invoking a BPEL process.
     * 
     * @param serviceId
     *            the service id of the process being called, if known
     * @param operation
     *            name of the operation
     * 
     * @return {@link MyRoleMessageExchange} the newly created message exchange
     */
    MyRoleMessageExchange createMessageExchange(String clientKey, QName serviceId, String operation)
            throws BpelEngineException;

    /**
     * Retrieve a message identified by the given identifer.
     * 
     * @param mexId
     *            message exhcange identifier
     * @return associated message exchange
     */
    MessageExchange getMessageExchange(String mexId);

}