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comparison jvmci/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java @ 22761:f2206f5bb62e

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removed @ServiceProvider mechanism (GRAAL-1380)
author Doug Simon <doug.simon@oracle.com>
date Wed, 30 Dec 2015 17:55:07 +0100
parents jvmci/jdk.vm.ci.service/src/jdk/vm/ci/service/Services.java@1bbd4a7c274b
children 4b58c92e939b
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22760:4cf1946f59fc 22761:f2206f5bb62e
1 /*
2 * Copyright (c) 2014, 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 jdk.vm.ci.services;
24
25 import java.util.Arrays;
26 import java.util.Collections;
27 import java.util.Formatter;
28 import java.util.List;
29
30 import sun.reflect.Reflection;
31
32 /**
33 * An mechanism for accessing service providers via JVMCI. These providers are loaded via a JVMCI
34 * class loader that is hidden from application code. Hence the {@link SecurityManager} checks in
35 * {@link #load(Class)} and {@link #loadSingle(Class, boolean)}.
36 */
37 public final class Services {
38
39 private Services() {
40 }
41
42 private static final String SUPPRESS_PROPERTY_NAME = "jvmci.service.suppressNoClassDefFoundError";
43
44 /**
45 * Determines whether to suppress the {@link NoClassDefFoundError} raised if a service provider
46 * class specified in a {@code <jre>/jvmci/services/*} file is missing.
47 */
48 private static final boolean SuppressNoClassDefFoundError = Boolean.getBoolean(SUPPRESS_PROPERTY_NAME);
49
50 private static final ClassValue<List<?>> cache = new ClassValue<List<?>>() {
51 @Override
52 protected List<?> computeValue(Class<?> type) {
53 try {
54 return Arrays.asList(getServiceImpls(type));
55 } catch (NoClassDefFoundError e) {
56 if (SuppressNoClassDefFoundError) {
57 return Collections.emptyList();
58 } else {
59 NoClassDefFoundError newEx = new NoClassDefFoundError(e.getMessage() + " (suppress with -D" + SUPPRESS_PROPERTY_NAME + "=true)");
60 if (e.getCause() != null) {
61 newEx.initCause(e.getCause());
62 }
63 throw newEx;
64 }
65 }
66 }
67 };
68
69 /**
70 * Gets an {@link Iterable} of the JVMCI providers available for a given service.
71 *
72 * @throws SecurityException if a security manager is present and it denies
73 * <tt>{@link RuntimePermission}("jvmciServices")</tt>
74 */
75 @SuppressWarnings("unchecked")
76 public static <S> Iterable<S> load(Class<S> service) {
77 SecurityManager sm = System.getSecurityManager();
78 if (sm != null) {
79 sm.checkPermission(new RuntimePermission("jvmciServices"));
80 }
81 try {
82 return (Iterable<S>) cache.get(service);
83 } catch (UnsatisfiedLinkError e) {
84 return Collections.emptyList();
85 }
86 }
87
88 /**
89 * Gets the JVMCI provider for a given service for which at most one provider must be available.
90 *
91 * @param service the service whose provider is being requested
92 * @param required specifies if an {@link InternalError} should be thrown if no provider of
93 * {@code service} is available
94 * @throws SecurityException if a security manager is present and it denies
95 * <tt>{@link RuntimePermission}("jvmciServices")</tt>
96 */
97 @SuppressWarnings({"unchecked"})
98 public static <S> S loadSingle(Class<S> service, boolean required) {
99 SecurityManager sm = System.getSecurityManager();
100 if (sm != null) {
101 sm.checkPermission(new RuntimePermission("jvmciServices"));
102 }
103 Iterable<S> providers;
104 try {
105 providers = (Iterable<S>) cache.get(service);
106 } catch (UnsatisfiedLinkError e) {
107 providers = Collections.emptyList();
108 }
109
110 S singleProvider = null;
111 for (S provider : providers) {
112 if (singleProvider != null) {
113 throw new InternalError(String.format("Multiple %s providers found: %s, %s", service.getName(), singleProvider.getClass().getName(), provider.getClass().getName()));
114 }
115 singleProvider = provider;
116 }
117 if (singleProvider == null && required) {
118 String javaHome = System.getProperty("java.home");
119 String vmName = System.getProperty("java.vm.name");
120 Formatter errorMessage = new Formatter();
121 errorMessage.format("The VM does not expose required service %s.%n", service.getName());
122 errorMessage.format("Currently used Java home directory is %s.%n", javaHome);
123 errorMessage.format("Currently used VM configuration is: %s", vmName);
124 throw new UnsupportedOperationException(errorMessage.toString());
125 }
126 return singleProvider;
127 }
128
129 static {
130 Reflection.registerMethodsToFilter(Services.class, "getServiceImpls");
131 Reflection.registerFieldsToFilter(Services.class, "cache");
132 }
133
134 private static native <S> S[] getServiceImpls(Class<?> service);
135 }