CompositeGuardingDynamicLinker.java revision 1612:0da44ab8c417
1/* 2 * Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26/* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file, and Oracle licenses the original version of this file under the BSD 31 * license: 32 */ 33/* 34 Copyright 2009-2013 Attila Szegedi 35 36 Licensed under both the Apache License, Version 2.0 (the "Apache License") 37 and the BSD License (the "BSD License"), with licensee being free to 38 choose either of the two at their discretion. 39 40 You may not use this file except in compliance with either the Apache 41 License or the BSD License. 42 43 If you choose to use this file in compliance with the Apache License, the 44 following notice applies to you: 45 46 You may obtain a copy of the Apache License at 47 48 http://www.apache.org/licenses/LICENSE-2.0 49 50 Unless required by applicable law or agreed to in writing, software 51 distributed under the License is distributed on an "AS IS" BASIS, 52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 53 implied. See the License for the specific language governing 54 permissions and limitations under the License. 55 56 If you choose to use this file in compliance with the BSD License, the 57 following notice applies to you: 58 59 Redistribution and use in source and binary forms, with or without 60 modification, are permitted provided that the following conditions are 61 met: 62 * Redistributions of source code must retain the above copyright 63 notice, this list of conditions and the following disclaimer. 64 * Redistributions in binary form must reproduce the above copyright 65 notice, this list of conditions and the following disclaimer in the 66 documentation and/or other materials provided with the distribution. 67 * Neither the name of the copyright holder nor the names of 68 contributors may be used to endorse or promote products derived from 69 this software without specific prior written permission. 70 71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER 75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 82*/ 83 84package jdk.dynalink.linker.support; 85 86import java.util.LinkedList; 87import java.util.List; 88import java.util.Objects; 89import jdk.dynalink.linker.GuardedInvocation; 90import jdk.dynalink.linker.GuardingDynamicLinker; 91import jdk.dynalink.linker.LinkRequest; 92import jdk.dynalink.linker.LinkerServices; 93 94/** 95 * A {@link GuardingDynamicLinker} that delegates sequentially to a list of 96 * other guarding dynamic linkers in its 97 * {@link #getGuardedInvocation(LinkRequest, LinkerServices)}. 98 */ 99public class CompositeGuardingDynamicLinker implements GuardingDynamicLinker { 100 101 private final GuardingDynamicLinker[] linkers; 102 103 /** 104 * Creates a new composite linker. 105 * 106 * @param linkers a list of component linkers. 107 * @throws NullPointerException if {@code linkers} or any of its elements 108 * are null. 109 */ 110 public CompositeGuardingDynamicLinker(final Iterable<? extends GuardingDynamicLinker> linkers) { 111 final List<GuardingDynamicLinker> l = new LinkedList<>(); 112 for(final GuardingDynamicLinker linker: linkers) { 113 l.add(Objects.requireNonNull(linker)); 114 } 115 this.linkers = l.toArray(new GuardingDynamicLinker[0]); 116 } 117 118 /** 119 * Delegates the call to its component linkers. The first non-null value 120 * returned from a component linker is returned. If no component linker 121 * returns a non-null invocation, null is returned. 122 * @param linkRequest the object describing the request for linking a 123 * particular invocation 124 * @param linkerServices linker services 125 * @return the first non-null return value from a component linker, or null 126 * if none of the components returned a non-null. 127 */ 128 @Override 129 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) 130 throws Exception { 131 for(final GuardingDynamicLinker linker: linkers) { 132 final GuardedInvocation invocation = linker.getGuardedInvocation(linkRequest, linkerServices); 133 if(invocation != null) { 134 return invocation; 135 } 136 } 137 return null; 138 } 139} 140