    001    // Copyright 2009 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    //     http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.ioc.services;
    016
    017    import org.apache.tapestry5.ioc.Invokable;
    018
    019    import java.util.concurrent.Future;
    020
    021    /**
    022     * A service that allows work to occur in parallel using a thread pool. The thread pool is started lazily, and is
    023     * shutdown when the Registry is shutdown.
    024     *
    025     * @see org.apache.tapestry5.ioc.IOCSymbols
    026     * @since 5.1.0.1
    027     */
    028    public interface ParallelExecutor
    029    {
    030        /**
    031         * Submits the invocable object to be executed in a pooled thread. Returns a Future object representing the eventual
    032         * result of the invocable's operation.  The actual operation will be wrapped such that {@link
    033         * PerthreadManager#cleanup()} is invoked after the operation completes.
    034         *
    035         * @param invocable to execute in a thread
    036         * @param <T>
    037         * @return Future result of that invocation
    038         */
    039        <T> Future<T> invoke(Invokable<T> invocable);
    040
    041        /**
    042         * As with {@link #invoke(org.apache.tapestry5.ioc.Invokable)}, but the result is wrapped inside a {@linkplain
    043         * org.apache.tapestry5.ioc.services.ThunkCreator thunk}. Invoking methods on the thunk will block until the value
    044         * is available.
    045         *
    046         * @param proxyType return type, used to create the thunk
    047         * @param invocable object that will eventually execute and return a value
    048         * @param <T>
    049         * @return the thunk
    050         */
    051        <T> T invoke(Class<T> proxyType, Invokable<T> invocable);
    052    }