8168317: [JVMCI] use reflection instead of jdk 9 Module API in Services.java
Reviewed-by: iveresov, twisti
--- a/hotspot/src/jdk.vm.ci/share/classes/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java Mon Oct 24 16:27:13 2016 +0000
+++ b/hotspot/src/jdk.vm.ci/share/classes/jdk.vm.ci.services/src/jdk/vm/ci/services/Services.java Mon Oct 24 11:48:30 2016 -0700
@@ -22,7 +22,8 @@
*/
package jdk.vm.ci.services;
-import java.lang.reflect.Module;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
import java.util.Formatter;
import java.util.Iterator;
import java.util.ServiceConfigurationError;
@@ -36,11 +37,62 @@
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 {@link Module} to provide backwards
+ * 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
@@ -52,15 +104,19 @@
if (sm != null) {
sm.checkPermission(new JVMCIPermission());
}
- Module jvmci = Services.class.getModule();
- Module requestorModule = requestor.getModule();
- if (jvmci != requestorModule) {
- for (String pkg : jvmci.getPackages()) {
- // Export all JVMCI packages dynamically instead
- // of requiring a long list of --add-exports
- // options on the JVM command line.
- if (!jvmci.isExported(pkg, requestorModule)) {
- jvmci.addExports(pkg, requestorModule);
+ if (JAVA_SPECIFICATION_VERSION >= 9) {
+ Object jvmci = invoke(getModule, Services.class);
+ Object requestorModule = invoke(getModule, requestor);
+ if (jvmci != requestorModule) {
+ 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);
+ }
}
}
}
@@ -77,8 +133,10 @@
if (sm != null) {
sm.checkPermission(new JVMCIPermission());
}
- Module jvmci = Services.class.getModule();
- jvmci.addUses(service);
+ 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());
@@ -98,8 +156,10 @@
if (sm != null) {
sm.checkPermission(new JVMCIPermission());
}
- Module jvmci = Services.class.getModule();
- jvmci.addUses(service);
+ 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;