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src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java
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*** 20,188 ****
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.vm.ci.services;
- import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
! import java.util.Formatter;
! import java.util.Iterator;
! import java.util.ServiceConfigurationError;
! import java.util.ServiceLoader;
! import java.util.Set;
/**
! * A mechanism for accessing service providers via JVMCI.
*/
public final class Services {
private Services() {
}
- private static int getJavaSpecificationVersion() {
- String value = System.getProperty("java.specification.version");
- if (value.startsWith("1.")) {
- value = value.substring(2);
- }
- return Integer.parseInt(value);
- }
-
/**
! * The integer value corresponding to the value of the {@code java.specification.version} system
! * property after any leading {@code "1."} has been stripped.
*/
- public static final int JAVA_SPECIFICATION_VERSION = getJavaSpecificationVersion();
-
- // Use reflection so that this compiles on Java 8
- private static final Method getModule;
- private static final Method getPackages;
- private static final Method addUses;
- private static final Method isExported;
- private static final Method addExports;
-
- static {
- if (JAVA_SPECIFICATION_VERSION >= 9) {
- try {
- getModule = Class.class.getMethod("getModule");
- Class<?> moduleClass = getModule.getReturnType();
- getPackages = moduleClass.getMethod("getPackages");
- addUses = moduleClass.getMethod("addUses", Class.class);
- isExported = moduleClass.getMethod("isExported", String.class, moduleClass);
- addExports = moduleClass.getMethod("addExports", String.class, moduleClass);
- } catch (NoSuchMethodException | SecurityException e) {
- throw new InternalError(e);
- }
- } else {
- getModule = null;
- getPackages = null;
- addUses = null;
- isExported = null;
- addExports = null;
- }
- }
-
@SuppressWarnings("unchecked")
! static <T> T invoke(Method method, Object receiver, Object... args) {
! try {
! return (T) method.invoke(receiver, args);
! } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
! throw new InternalError(e);
! }
! }
!
! /**
! * Performs any required security checks and dynamic reconfiguration to allow the module of a
! * given class to access the classes in the JVMCI module.
! *
! * Note: This API uses {@link Class} instead of {@code Module} to provide backwards
! * compatibility for JVMCI clients compiled against a JDK release earlier than 9.
! *
! * @param requestor a class requesting access to the JVMCI module for its module
! * @throws SecurityException if a security manager is present and it denies
! * {@link JVMCIPermission}
! */
! public static void exportJVMCITo(Class<?> requestor) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new JVMCIPermission());
}
! if (JAVA_SPECIFICATION_VERSION >= 9) {
! Object jvmci = invoke(getModule, Services.class);
! Object requestorModule = invoke(getModule, requestor);
! if (jvmci != requestorModule) {
! Set<String> packages = invoke(getPackages, jvmci);
! for (String pkg : packages) {
! // Export all JVMCI packages dynamically instead
! // of requiring a long list of --add-exports
! // options on the JVM command line.
! boolean exported = invoke(isExported, jvmci, pkg, requestorModule);
! if (!exported) {
! invoke(addExports, jvmci, pkg, requestorModule);
! }
! }
! }
! }
! }
!
! /**
! * Gets an {@link Iterable} of the JVMCI providers available for a given service.
! *
! * @throws SecurityException if a security manager is present and it denies
! * {@link JVMCIPermission}
! */
! public static <S> Iterable<S> load(Class<S> service) {
! SecurityManager sm = System.getSecurityManager();
! if (sm != null) {
! sm.checkPermission(new JVMCIPermission());
}
- if (JAVA_SPECIFICATION_VERSION >= 9) {
- Object jvmci = invoke(getModule, Services.class);
- invoke(addUses, jvmci, service);
- }
-
- // Restrict JVMCI clients to be on the class path or module path
- return ServiceLoader.load(service, ClassLoader.getSystemClassLoader());
}
/**
! * 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
! * {@link JVMCIPermission}
*/
! public static <S> S loadSingle(Class<S> service, boolean required) {
! SecurityManager sm = System.getSecurityManager();
! if (sm != null) {
! sm.checkPermission(new JVMCIPermission());
! }
! if (JAVA_SPECIFICATION_VERSION >= 9) {
! Object jvmci = invoke(getModule, Services.class);
! invoke(addUses, jvmci, service);
! }
! // Restrict JVMCI clients to be on the class path or module path
! Iterable<S> providers = ServiceLoader.load(service, ClassLoader.getSystemClassLoader());
! S singleProvider = null;
try {
! for (Iterator<S> it = providers.iterator(); it.hasNext();) {
! singleProvider = it.next();
! if (it.hasNext()) {
! throw new InternalError(String.format("Multiple %s providers found", service.getName()));
! }
! }
! } catch (ServiceConfigurationError e) {
! // If the service is required we will bail out below.
! }
! 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;
}
}
--- 20,66 ----
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.vm.ci.services;
import java.lang.reflect.Method;
! import java.util.Map;
/**
! * Provides utilities needed by JVMCI clients.
! *
! * This class must be compilable on JDK 8 and so use of API added in JDK 9 is made via reflection.
*/
public final class Services {
private Services() {
}
/**
! * Gets an unmodifiable copy of the system properties saved when {@link System} is initialized.
*/
@SuppressWarnings("unchecked")
! public static Map<String, String> getSavedProperties() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new JVMCIPermission());
}
! try {
! Class<?> vmClass = Class.forName("jdk.internal.misc.VM");
! Method m = vmClass.getMethod("getSavedProperties");
! return (Map<String, String>) m.invoke(null);
! } catch (Exception e) {
! throw new InternalError(e);
}
}
/**
! * Causes the JVMCI subsystem to be initialized if it isn't already initialized.
*/
! public static void initializeJVMCI() {
try {
! Class.forName("jdk.vm.ci.runtime.JVMCI");
! } catch (ClassNotFoundException e) {
! throw new InternalError(e);
}
}
}
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