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    }