core/api/src/main/java/org/apache/polygene/api/unitofwork/UnitOfWorkCallback.java

/*
 *  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.polygene.api.unitofwork;

/**
 * Callback interface for UnitOfWork completion or discard. Implementations
 * of this interface can be registered through {@link UnitOfWork#addUnitOfWorkCallback(UnitOfWorkCallback)}.
 *
 * If Entities implement this interface they will also receive invocations of this callback interface.
 */
public interface UnitOfWorkCallback
{
    /**
     * This is called before the completion of the UnitOfWork.
     * The callback may do any validation checks.
     *
     * @throws UnitOfWorkCompletionException if there is any reason why the UnitOfWork is not in a valid state to be
     *                                       completed
     */
    void beforeCompletion()
        throws UnitOfWorkCompletionException;

    /**
     * This is called after the completion or discarding
     * of the UnitOfWork. The callback may do any cleanup
     * necessary related to the UnitOfWork. Note that the
     * UnitOfWork is no longer active when this method is
     * called, so no methods on it may be invoked.
     *
     * @param status the UnitOfWork status
     */
    void afterCompletion( UnitOfWorkStatus status );

    enum UnitOfWorkStatus
    {
        COMPLETED, DISCARDED
    }
}