Mercurial > hg > graal-jvmci-8
diff jvmci/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java @ 22761:f2206f5bb62e
removed @ServiceProvider mechanism (GRAAL-1380)
author | Doug Simon <doug.simon@oracle.com> |
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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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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jvmci/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java Wed Dec 30 17:55:07 2015 +0100 @@ -0,0 +1,135 @@ +/* + * Copyright (c) 2014, 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 + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * 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. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package jdk.vm.ci.services; + +import java.util.Arrays; +import java.util.Collections; +import java.util.Formatter; +import java.util.List; + +import sun.reflect.Reflection; + +/** + * An mechanism for accessing service providers via JVMCI. These providers are loaded via a JVMCI + * class loader that is hidden from application code. Hence the {@link SecurityManager} checks in + * {@link #load(Class)} and {@link #loadSingle(Class, boolean)}. + */ +public final class Services { + + private Services() { + } + + private static final String SUPPRESS_PROPERTY_NAME = "jvmci.service.suppressNoClassDefFoundError"; + + /** + * Determines whether to suppress the {@link NoClassDefFoundError} raised if a service provider + * class specified in a {@code <jre>/jvmci/services/*} file is missing. + */ + private static final boolean SuppressNoClassDefFoundError = Boolean.getBoolean(SUPPRESS_PROPERTY_NAME); + + private static final ClassValue<List<?>> cache = new ClassValue<List<?>>() { + @Override + protected List<?> computeValue(Class<?> type) { + try { + return Arrays.asList(getServiceImpls(type)); + } catch (NoClassDefFoundError e) { + if (SuppressNoClassDefFoundError) { + return Collections.emptyList(); + } else { + NoClassDefFoundError newEx = new NoClassDefFoundError(e.getMessage() + " (suppress with -D" + SUPPRESS_PROPERTY_NAME + "=true)"); + if (e.getCause() != null) { + newEx.initCause(e.getCause()); + } + throw newEx; + } + } + } + }; + + /** + * Gets an {@link Iterable} of the JVMCI providers available for a given service. + * + * @throws SecurityException if a security manager is present and it denies + * <tt>{@link RuntimePermission}("jvmciServices")</tt> + */ + @SuppressWarnings("unchecked") + public static <S> Iterable<S> load(Class<S> service) { + SecurityManager sm = System.getSecurityManager(); + if (sm != null) { + sm.checkPermission(new RuntimePermission("jvmciServices")); + } + try { + return (Iterable<S>) cache.get(service); + } catch (UnsatisfiedLinkError e) { + return Collections.emptyList(); + } + } + + /** + * Gets the JVMCI provider for a given service for which at most one provider must be available. + * + * @param service the service whose provider is being requested + * @param required specifies if an {@link InternalError} should be thrown if no provider of + * {@code service} is available + * @throws SecurityException if a security manager is present and it denies + * <tt>{@link RuntimePermission}("jvmciServices")</tt> + */ + @SuppressWarnings({"unchecked"}) + public static <S> S loadSingle(Class<S> service, boolean required) { + SecurityManager sm = System.getSecurityManager(); + if (sm != null) { + sm.checkPermission(new RuntimePermission("jvmciServices")); + } + Iterable<S> providers; + try { + providers = (Iterable<S>) cache.get(service); + } catch (UnsatisfiedLinkError e) { + providers = Collections.emptyList(); + } + + S singleProvider = null; + for (S provider : providers) { + if (singleProvider != null) { + throw new InternalError(String.format("Multiple %s providers found: %s, %s", service.getName(), singleProvider.getClass().getName(), provider.getClass().getName())); + } + singleProvider = provider; + } + if (singleProvider == null && required) { + String javaHome = System.getProperty("java.home"); + String vmName = System.getProperty("java.vm.name"); + Formatter errorMessage = new Formatter(); + errorMessage.format("The VM does not expose required service %s.%n", service.getName()); + errorMessage.format("Currently used Java home directory is %s.%n", javaHome); + errorMessage.format("Currently used VM configuration is: %s", vmName); + throw new UnsupportedOperationException(errorMessage.toString()); + } + return singleProvider; + } + + static { + Reflection.registerMethodsToFilter(Services.class, "getServiceImpls"); + Reflection.registerFieldsToFilter(Services.class, "cache"); + } + + private static native <S> S[] getServiceImpls(Class<?> service); +}