1 /* 2 * Copyright (c) 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.serviceprovider; 24 25 import java.util.Iterator; 26 import java.util.ServiceConfigurationError; 27 import java.util.ServiceLoader; 28 29 import jdk.vm.ci.services.JVMCIPermission; 30 import jdk.vm.ci.services.Services; 31 32 /** 33 * A mechanism for accessing service providers that abstracts over whether Graal is running on 34 * JVMCI-8 or JVMCI-9. In JVMCI-8, a JVMCI specific mechanism is used to lookup services via the 35 * hidden JVMCI class loader. in JVMCI-9, the standard {@link ServiceLoader} mechanism is used. 36 */ 37 public final class GraalServices { 38 39 private GraalServices() { 40 } 41 42 public static final boolean Java8OrEarlier = System.getProperty("java.specification.version").compareTo("1.9") < 0; 43 44 /** 45 * Gets an {@link Iterable} of the providers available for a given service. 46 * 47 * @throws SecurityException if on JDK8 and a security manager is present and it denies 48 * {@link JVMCIPermission} 49 */ 50 public static <S> Iterable<S> load(Class<S> service) { 51 assert !service.getName().startsWith("jdk.vm.ci") : "JVMCI services must be loaded via " + Services.class.getName(); 52 if (Java8OrEarlier) { 53 return Services.load(service); 54 } 55 ServiceLoader<S> iterable = ServiceLoader.load(service); 56 return new Iterable<S>() { 57 @Override 58 public Iterator<S> iterator() { 59 Iterator<S> iterator = iterable.iterator(); 60 return new Iterator<S>() { 61 @Override 62 public boolean hasNext() { 63 return iterator.hasNext(); 64 } 65 66 @Override 67 public S next() { 68 S provider = iterator.next(); 69 // Allow Graal extensions to access JVMCI assuming they have JVMCIPermission 70 Services.exportJVMCITo(provider.getClass()); 71 return provider; 72 } 73 74 @Override 75 public void remove() { 76 iterator.remove(); 77 } 78 }; 79 } 80 }; 81 } 82 83 /** 84 * Gets the provider for a given service for which at most one provider must be available. 85 * 86 * @param service the service whose provider is being requested 87 * @param required specifies if an {@link InternalError} should be thrown if no provider of 88 * {@code service} is available 89 * @return the requested provider if available else {@code null} 90 * @throws SecurityException if on JDK8 and a security manager is present and it denies 91 * {@link JVMCIPermission} 92 */ 93 public static <S> S loadSingle(Class<S> service, boolean required) { 94 assert !service.getName().startsWith("jdk.vm.ci") : "JVMCI services must be loaded via " + Services.class.getName(); 95 if (Java8OrEarlier) { 96 return Services.loadSingle(service, required); 97 } 98 Iterable<S> providers = ServiceLoader.load(service); 99 S singleProvider = null; 100 try { 101 for (Iterator<S> it = providers.iterator(); it.hasNext();) { 102 singleProvider = it.next(); 103 if (it.hasNext()) { 104 throw new InternalError(String.format("Multiple %s providers found", service.getName())); 105 } 106 } 107 } catch (ServiceConfigurationError e) { 108 // If the service is required we will bail out below. 109 } 110 if (singleProvider == null) { 111 if (required) { 112 throw new InternalError(String.format("No provider for %s found", service.getName())); 113 } 114 } else { 115 // Allow Graal extensions to access JVMCI assuming they have JVMCIPermission 116 Services.exportJVMCITo(singleProvider.getClass()); 117 } 118 return singleProvider; 119 } 120 }