BatchAction.java

/*
 * Copyright 2011 ArcBees Inc.
 *
 * Licensed 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 com.gwtplatform.dispatch.rpc.shared;

/**
 * This provides a simple way to send multiple actions to be executed in sequence. If any fail, the rules for the
 * {@link OnException} value provided in the constructor determine the outcome.
 */
public abstract class BatchAction implements Action<BatchResult> {
    /**
     * {@link BatchAction}'s enumeration of possible outcomes when there is an exception.
     */
    public enum OnException {
        /**
         * If specified, the batch will continue if an action fails. The matching {@link Result} in the
         * {@link BatchResult#getResults()} will be <code>null</code>.
         */
        CONTINUE,
        /**
         * If specified, the batch will stop processing and roll back any executed actions from the batch, and throw the
         * exception.
         */
        ROLLBACK
    }

    private Action<?>[] actions;

    private OnException onException;

    /**
     * Constructs a new batch action, which will attempt to execute the provided list of actions in order. If there is a
     * failure, it will follow the rules specified by <code>onException</code>.
     *
     * @param onException If there is an exception, specify the behaviour.
     * @param actions     The list of actions to execute.
     */
    public BatchAction(OnException onException, Action<?>... actions) {
        this.onException = onException;
        this.actions = actions;
    }

    /**
     * Used for serialization only.
     */
    BatchAction() {
    }

    /**
     * The list of actions to execute.
     *
     * @return The actions.
     */
    public Action<?>[] getActions() {
        return actions;
    }

    /**
     * The expected behaviour if any of the sub-actions throw an exception.
     *
     * @return The exception handling behaviour.
     */
    public OnException getOnException() {
        return onException;
    }
}