author | alanb |
Fri, 07 Apr 2017 08:04:46 +0000 | |
changeset 44520 | 0553e129e0ec |
parent 43972 | 1ade39b8381b |
child 44836 | 45196b7066e3 |
permissions | -rw-r--r-- |
43972 | 1 |
/* |
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* Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package jdk.vm.ci.services; |
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import java.lang.reflect.InvocationTargetException; |
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import java.lang.reflect.Method; |
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import java.util.Formatter; |
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import java.util.Iterator; |
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import java.util.ServiceConfigurationError; |
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import java.util.ServiceLoader; |
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44520
0553e129e0ec
8177530: Module system implementation refresh (4/2017)
alanb
parents:
43972
diff
changeset
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import java.util.Set; |
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/** |
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* A mechanism for accessing service providers via JVMCI. |
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*/ |
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public final class Services { |
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private Services() { |
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} |
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private static int getJavaSpecificationVersion() { |
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String value = System.getProperty("java.specification.version"); |
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if (value.startsWith("1.")) { |
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value = value.substring(2); |
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} |
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return Integer.parseInt(value); |
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} |
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/** |
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* The integer value corresponding to the value of the {@code java.specification.version} system |
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* property after any leading {@code "1."} has been stripped. |
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*/ |
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public static final int JAVA_SPECIFICATION_VERSION = getJavaSpecificationVersion(); |
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// Use reflection so that this compiles on Java 8 |
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private static final Method getModule; |
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private static final Method getPackages; |
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private static final Method addUses; |
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private static final Method isExported; |
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private static final Method addExports; |
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static { |
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if (JAVA_SPECIFICATION_VERSION >= 9) { |
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try { |
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getModule = Class.class.getMethod("getModule"); |
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Class<?> moduleClass = getModule.getReturnType(); |
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getPackages = moduleClass.getMethod("getPackages"); |
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addUses = moduleClass.getMethod("addUses", Class.class); |
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isExported = moduleClass.getMethod("isExported", String.class, moduleClass); |
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addExports = moduleClass.getMethod("addExports", String.class, moduleClass); |
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} catch (NoSuchMethodException | SecurityException e) { |
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throw new InternalError(e); |
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} |
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} else { |
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getModule = null; |
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getPackages = null; |
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addUses = null; |
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isExported = null; |
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addExports = null; |
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} |
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} |
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@SuppressWarnings("unchecked") |
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static <T> T invoke(Method method, Object receiver, Object... args) { |
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try { |
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return (T) method.invoke(receiver, args); |
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} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { |
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throw new InternalError(e); |
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} |
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} |
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/** |
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* Performs any required security checks and dynamic reconfiguration to allow the module of a |
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* given class to access the classes in the JVMCI module. |
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* |
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* Note: This API uses {@link Class} instead of {@code Module} to provide backwards |
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* compatibility for JVMCI clients compiled against a JDK release earlier than 9. |
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* |
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* @param requestor a class requesting access to the JVMCI module for its module |
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* @throws SecurityException if a security manager is present and it denies |
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* {@link JVMCIPermission} |
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*/ |
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public static void exportJVMCITo(Class<?> requestor) { |
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SecurityManager sm = System.getSecurityManager(); |
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if (sm != null) { |
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sm.checkPermission(new JVMCIPermission()); |
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} |
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if (JAVA_SPECIFICATION_VERSION >= 9) { |
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Object jvmci = invoke(getModule, Services.class); |
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Object requestorModule = invoke(getModule, requestor); |
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if (jvmci != requestorModule) { |
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44520
0553e129e0ec
8177530: Module system implementation refresh (4/2017)
alanb
parents:
43972
diff
changeset
|
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Set<String> packages = invoke(getPackages, jvmci); |
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for (String pkg : packages) { |
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// Export all JVMCI packages dynamically instead |
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// of requiring a long list of --add-exports |
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// options on the JVM command line. |
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boolean exported = invoke(isExported, jvmci, pkg, requestorModule); |
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if (!exported) { |
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invoke(addExports, jvmci, pkg, requestorModule); |
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} |
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} |
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} |
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} |
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} |
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/** |
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* Gets an {@link Iterable} of the JVMCI providers available for a given service. |
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* |
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* @throws SecurityException if a security manager is present and it denies |
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* {@link JVMCIPermission} |
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*/ |
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public static <S> Iterable<S> load(Class<S> service) { |
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SecurityManager sm = System.getSecurityManager(); |
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if (sm != null) { |
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sm.checkPermission(new JVMCIPermission()); |
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} |
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if (JAVA_SPECIFICATION_VERSION >= 9) { |
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Object jvmci = invoke(getModule, Services.class); |
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invoke(addUses, jvmci, service); |
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} |
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// Restrict JVMCI clients to be on the class path or module path |
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return ServiceLoader.load(service, ClassLoader.getSystemClassLoader()); |
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} |
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/** |
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* Gets the JVMCI provider for a given service for which at most one provider must be available. |
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* |
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* @param service the service whose provider is being requested |
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* @param required specifies if an {@link InternalError} should be thrown if no provider of |
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* {@code service} is available |
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* @throws SecurityException if a security manager is present and it denies |
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* {@link JVMCIPermission} |
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*/ |
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public static <S> S loadSingle(Class<S> service, boolean required) { |
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SecurityManager sm = System.getSecurityManager(); |
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if (sm != null) { |
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sm.checkPermission(new JVMCIPermission()); |
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} |
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if (JAVA_SPECIFICATION_VERSION >= 9) { |
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Object jvmci = invoke(getModule, Services.class); |
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invoke(addUses, jvmci, service); |
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} |
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// Restrict JVMCI clients to be on the class path or module path |
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Iterable<S> providers = ServiceLoader.load(service, ClassLoader.getSystemClassLoader()); |
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S singleProvider = null; |
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try { |
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for (Iterator<S> it = providers.iterator(); it.hasNext();) { |
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singleProvider = it.next(); |
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if (it.hasNext()) { |
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throw new InternalError(String.format("Multiple %s providers found", service.getName())); |
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} |
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} |
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} catch (ServiceConfigurationError e) { |
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// If the service is required we will bail out below. |
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} |
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if (singleProvider == null && required) { |
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String javaHome = System.getProperty("java.home"); |
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String vmName = System.getProperty("java.vm.name"); |
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Formatter errorMessage = new Formatter(); |
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errorMessage.format("The VM does not expose required service %s.%n", service.getName()); |
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errorMessage.format("Currently used Java home directory is %s.%n", javaHome); |
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errorMessage.format("Currently used VM configuration is: %s", vmName); |
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throw new UnsupportedOperationException(errorMessage.toString()); |
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} |
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return singleProvider; |
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} |
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} |