    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
    015package org.apache.tapestry5.ioc.services;
    016
    017import org.apache.tapestry5.ioc.Invokable;
    018
    019import 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 */
    028public 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}