| /* |
| * Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
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| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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| * questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file, and Oracle licenses the original version of this file under the BSD |
| * license: |
| */ |
| /* |
| Copyright 2009-2013 Attila Szegedi |
| |
| Licensed under both the Apache License, Version 2.0 (the "Apache License") |
| and the BSD License (the "BSD License"), with licensee being free to |
| choose either of the two at their discretion. |
| |
| You may not use this file except in compliance with either the Apache |
| License or the BSD License. |
| |
| If you choose to use this file in compliance with the Apache License, the |
| following notice applies to you: |
| |
| You may obtain a copy of the Apache License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| implied. See the License for the specific language governing |
| permissions and limitations under the License. |
| |
| If you choose to use this file in compliance with the BSD License, the |
| following notice applies to you: |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| * Neither the name of the copyright holder nor the names of |
| contributors may be used to endorse or promote products derived from |
| this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
| BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
| BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package jdk.dynalink.linker.support; |
| |
| import java.util.Collections; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Objects; |
| import jdk.dynalink.linker.GuardedInvocation; |
| import jdk.dynalink.linker.GuardingDynamicLinker; |
| import jdk.dynalink.linker.LinkRequest; |
| import jdk.dynalink.linker.LinkerServices; |
| import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker; |
| |
| /** |
| * A composite type-based guarding dynamic linker. When a receiver of a not yet |
| * seen class is encountered, all linkers are queried sequentially on their |
| * {@link TypeBasedGuardingDynamicLinker#canLinkType(Class)} method. The linkers |
| * returning true are then bound to the class, and next time a receiver of same |
| * type is encountered, the linking is delegated to those linkers only, speeding |
| * up dispatch. |
| */ |
| public class CompositeTypeBasedGuardingDynamicLinker implements TypeBasedGuardingDynamicLinker { |
| // Using a separate static class instance so there's no strong reference from the class value back to the composite |
| // linker. |
| private static class ClassToLinker extends ClassValue<List<TypeBasedGuardingDynamicLinker>> { |
| private static final List<TypeBasedGuardingDynamicLinker> NO_LINKER = Collections.emptyList(); |
| private final TypeBasedGuardingDynamicLinker[] linkers; |
| private final List<TypeBasedGuardingDynamicLinker>[] singletonLinkers; |
| |
| @SuppressWarnings({"unchecked", "rawtypes"}) |
| ClassToLinker(final TypeBasedGuardingDynamicLinker[] linkers) { |
| this.linkers = linkers; |
| singletonLinkers = new List[linkers.length]; |
| for(int i = 0; i < linkers.length; ++i) { |
| singletonLinkers[i] = Collections.singletonList(linkers[i]); |
| } |
| } |
| |
| @SuppressWarnings("fallthrough") |
| @Override |
| protected List<TypeBasedGuardingDynamicLinker> computeValue(final Class<?> clazz) { |
| List<TypeBasedGuardingDynamicLinker> list = NO_LINKER; |
| for(int i = 0; i < linkers.length; ++i) { |
| final TypeBasedGuardingDynamicLinker linker = linkers[i]; |
| if(linker.canLinkType(clazz)) { |
| switch(list.size()) { |
| case 0: { |
| list = singletonLinkers[i]; |
| break; |
| } |
| case 1: { |
| list = new LinkedList<>(list); |
| } |
| default: { |
| list.add(linker); |
| } |
| } |
| } |
| } |
| return list; |
| } |
| } |
| |
| private final ClassValue<List<TypeBasedGuardingDynamicLinker>> classToLinker; |
| |
| /** |
| * Creates a new composite type-based linker. |
| * |
| * @param linkers the component linkers |
| * @throws NullPointerException if {@code linkers} or any of its elements |
| * are null. |
| */ |
| public CompositeTypeBasedGuardingDynamicLinker(final Iterable<? extends TypeBasedGuardingDynamicLinker> linkers) { |
| final List<TypeBasedGuardingDynamicLinker> l = new LinkedList<>(); |
| for(final TypeBasedGuardingDynamicLinker linker: linkers) { |
| l.add(Objects.requireNonNull(linker)); |
| } |
| this.classToLinker = new ClassToLinker(l.toArray(new TypeBasedGuardingDynamicLinker[0])); |
| } |
| |
| /** |
| * Returns true if at least one of the composite linkers returns true from |
| * {@link TypeBasedGuardingDynamicLinker#canLinkType(Class)} for the type. |
| * @param type the type to link |
| * @return true true if at least one of the composite linkers returns true |
| * from {@link TypeBasedGuardingDynamicLinker#canLinkType(Class)}, false |
| * otherwise. |
| */ |
| @Override |
| public boolean canLinkType(final Class<?> type) { |
| return !classToLinker.get(type).isEmpty(); |
| } |
| |
| @Override |
| public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) |
| throws Exception { |
| final Object obj = linkRequest.getReceiver(); |
| if(obj == null) { |
| return null; |
| } |
| for(final TypeBasedGuardingDynamicLinker linker: classToLinker.get(obj.getClass())) { |
| final GuardedInvocation invocation = linker.getGuardedInvocation(linkRequest, linkerServices); |
| if(invocation != null) { |
| return invocation; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Optimizes a list of type-based linkers. If a group of adjacent linkers in |
| * the list all implement {@link TypeBasedGuardingDynamicLinker}, they will |
| * be replaced with a single instance of |
| * {@link CompositeTypeBasedGuardingDynamicLinker} that contains them. |
| * |
| * @param linkers the list of linkers to optimize |
| * @return the optimized list |
| * @throws NullPointerException if {@code linkers} or any of its elements |
| * are null. |
| */ |
| public static List<GuardingDynamicLinker> optimize(final Iterable<? extends GuardingDynamicLinker> linkers) { |
| final List<GuardingDynamicLinker> llinkers = new LinkedList<>(); |
| final List<TypeBasedGuardingDynamicLinker> tblinkers = new LinkedList<>(); |
| for(final GuardingDynamicLinker linker: linkers) { |
| Objects.requireNonNull(linker); |
| if(linker instanceof TypeBasedGuardingDynamicLinker) { |
| tblinkers.add((TypeBasedGuardingDynamicLinker)linker); |
| } else { |
| addTypeBased(llinkers, tblinkers); |
| llinkers.add(linker); |
| } |
| } |
| addTypeBased(llinkers, tblinkers); |
| return llinkers; |
| } |
| |
| private static void addTypeBased(final List<GuardingDynamicLinker> llinkers, |
| final List<TypeBasedGuardingDynamicLinker> tblinkers) { |
| switch(tblinkers.size()) { |
| case 0: { |
| break; |
| } |
| case 1: { |
| llinkers.addAll(tblinkers); |
| tblinkers.clear(); |
| break; |
| } |
| default: { |
| llinkers.add(new CompositeTypeBasedGuardingDynamicLinker(tblinkers)); |
| tblinkers.clear(); |
| break; |
| } |
| } |
| } |
| } |