001/* 002 * The contents of this file are subject to the terms of the Common Development and 003 * Distribution License (the License). You may not use this file except in compliance with the 004 * License. 005 * 006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the 007 * specific language governing permission and limitations under the License. 008 * 009 * When distributing Covered Software, include this CDDL Header Notice in each file and include 010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL 011 * Header, with the fields enclosed by brackets [] replaced by your own identifying 012 * information: "Portions Copyright [year] [name of copyright owner]". 013 * 014 * Copyright 2015 ForgeRock AS. 015 */ 016package org.forgerock.http.spi; 017 018import java.util.Iterator; 019import java.util.ServiceLoader; 020 021import org.forgerock.util.Options; 022 023/** 024 * An SPI interface for implementing alternative service loading strategies. By 025 * default the HTTP framework will use a strategy based on {@link ServiceLoader} 026 * , but applications may choose to override with their own strategy if needed, 027 * for example when running in OSGI environments. 028 */ 029public interface Loader { 030 /** 031 * The default {@link Loader} implementation used throughout the HTTP 032 * framework. This implementation uses {@link ServiceLoader} for loading 033 * services. 034 */ 035 Loader SERVICE_LOADER = new Loader() { 036 @Override 037 public <S> S load(final Class<S> service, final Options options) { 038 final ServiceLoader<S> loader = ServiceLoader.load(service); 039 final Iterator<S> i = loader.iterator(); 040 return i.hasNext() ? i.next() : null; 041 }; 042 }; 043 044 /** 045 * Loads a service of the specified type. Implementations may customize 046 * their behavior based on the provided options, e.g. by using a user 047 * provided class loader. 048 * 049 * @param <S> 050 * The type of service to load. 051 * @param service 052 * The type of service to load. 053 * @param options 054 * The user provided options. 055 * @return The loaded service, or {@code null} if no corresponding service 056 * was found. 057 */ 058 <S> S load(final Class<S> service, final Options options); 059}