Implement service for registering, managing, and operating on remote Java proxies over the cluster communication service
Change-Id: I4576e3554cfad08747eed847b73fe695e219f3b8
diff --git a/core/net/src/main/java/org/onosproject/cluster/impl/AbstractProxyManager.java b/core/net/src/main/java/org/onosproject/cluster/impl/AbstractProxyManager.java
new file mode 100644
index 0000000..911b465
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/cluster/impl/AbstractProxyManager.java
@@ -0,0 +1,267 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.cluster.impl;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import com.google.common.collect.Maps;
+import org.onosproject.store.cluster.messaging.MessageSubject;
+
+/**
+ * Implementation of the proxy service.
+ */
+public abstract class AbstractProxyManager {
+
+ /**
+ * Wrapper for a proxy service which handles registration of proxy methods as {@code ClusterCommunicationService}
+ * subscribers.
+ */
+ class ProxyService {
+ private final Map<Method, OperationService> operations = Maps.newConcurrentMap();
+
+ ProxyService(
+ Object instance,
+ Class<?> type,
+ String prefix,
+ OperationServiceFactory syncServiceFactory,
+ OperationServiceFactory asyncServiceFactory) {
+ operations.putAll(getMethodMap(type, prefix).entrySet().stream()
+ .map(entry -> {
+ if (entry.getValue().type() == Operation.Type.SYNC) {
+ return Maps.immutableEntry(
+ entry.getKey(),
+ syncServiceFactory.create(instance, entry.getKey(), entry.getValue()));
+ } else {
+ return Maps.immutableEntry(
+ entry.getKey(),
+ asyncServiceFactory.create(instance, entry.getKey(), entry.getValue()));
+ }
+ }).collect(Collectors.toMap(e -> e.getKey(), e -> e.getValue())));
+ }
+
+ /**
+ * Closes the proxy service.
+ */
+ void close() {
+ operations.values().forEach(operation -> operation.close());
+ }
+ }
+
+ /**
+ * Operation service factory.
+ */
+ @FunctionalInterface
+ interface OperationServiceFactory {
+ OperationService create(Object instance, Method method, Operation operation);
+ }
+
+ /**
+ * Wrapper for a single proxy service operation which handles registration of subscribers and invocation
+ * of service instance methods.
+ */
+ abstract class OperationService {
+ protected final Object instance;
+ protected final Method method;
+ protected final Operation operation;
+
+ OperationService(Object instance, Method method, Operation operation) {
+ this.instance = instance;
+ this.method = method;
+ this.operation = operation;
+ }
+
+ /**
+ * Invokes the method with the given arguments.
+ *
+ * @param args the arguments with which to invoke the operation
+ * @param <T> the operation return type
+ * @return the operation return value
+ */
+ @SuppressWarnings("unchecked")
+ <T> T invoke(Object[] args) {
+ try {
+ return (T) method.invoke(instance, args);
+ } catch (IllegalAccessException | InvocationTargetException e) {
+ throw new IllegalStateException(e);
+ }
+ }
+
+ /**
+ * Closes the operation service.
+ */
+ abstract void close();
+ }
+
+ /**
+ * Proxy invocation handler which routes proxy method calls to the correct node and subscriber via
+ * {@code ClusterCommunicationService}.
+ */
+ class ProxyInvocationHandler implements InvocationHandler {
+ private final Map<Method, OperationHandler> handlers = Maps.newConcurrentMap();
+
+ ProxyInvocationHandler(
+ Class<?> type,
+ String prefix,
+ OperationHandlerFactory syncHandlerFactory,
+ OperationHandlerFactory asyncHandlerFactory) {
+ handlers.putAll(getMethodMap(type, prefix).entrySet().stream()
+ .map(entry -> {
+ if (entry.getValue().type() == Operation.Type.SYNC) {
+ return Maps.immutableEntry(entry.getKey(), syncHandlerFactory.create(entry.getValue()));
+ } else {
+ return Maps.immutableEntry(entry.getKey(), asyncHandlerFactory.create(entry.getValue()));
+ }
+ }).collect(Collectors.toMap(e -> e.getKey(), e -> e.getValue())));
+ }
+
+ @Override
+ public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+ OperationHandler handler = handlers.get(method);
+ if (handler == null) {
+ throw new IllegalStateException("Unknown proxy operation " + method.getName());
+ }
+ return handler.apply(args);
+ }
+ }
+
+ /**
+ * Operation handler factory.
+ */
+ @FunctionalInterface
+ interface OperationHandlerFactory {
+ OperationHandler create(Operation operation);
+ }
+
+ /**
+ * Invocation handler for an individual proxy operation.
+ */
+ abstract class OperationHandler implements Function<Object[], Object> {
+ protected final Operation operation;
+
+ OperationHandler(Operation operation) {
+ this.operation = operation;
+ }
+ }
+
+ /**
+ * Recursively finds operations defined by the given type and its implemented interfaces.
+ *
+ * @param type the type for which to find operations
+ * @param prefix the prefix with which to generate message subjects
+ * @return the operations defined by the given type and its parent interfaces
+ */
+ Map<Method, Operation> getMethodMap(Class<?> type, String prefix) {
+ String service = type.getCanonicalName().replace(".", "-");
+ Map<Method, Operation> methods = new HashMap<>();
+ for (Method method : type.getDeclaredMethods()) {
+ String name = method.getName();
+ if (methods.values().stream().anyMatch(op -> op.name.equals(name))) {
+ throw new IllegalArgumentException("Method " + name + " is ambiguous");
+ }
+
+ Class<?> returnType = method.getReturnType();
+ if (CompletableFuture.class.isAssignableFrom(returnType)) {
+ methods.put(method, new Operation(Operation.Type.ASYNC, prefix, service, name, method));
+ } else {
+ methods.put(method, new Operation(Operation.Type.SYNC, prefix, service, name, method));
+ }
+ }
+ for (Class<?> iface : type.getInterfaces()) {
+ methods.putAll(getMethodMap(iface, prefix));
+ }
+ return methods;
+ }
+
+ /**
+ * Simple data class for proxy operation metadata.
+ */
+ static class Operation {
+
+ /**
+ * Operation type.
+ */
+ enum Type {
+ SYNC,
+ ASYNC,
+ }
+
+ private final Type type;
+ private final String service;
+ private final String name;
+ private final Method method;
+ private final MessageSubject subject;
+
+ Operation(Type type, String prefix, String service, String name, Method method) {
+ this.type = type;
+ this.service = service;
+ this.name = name;
+ this.method = method;
+ this.subject = new MessageSubject(String.format("%s-%s-%s", prefix, service, name));
+ }
+
+ /**
+ * Returns the operation type.
+ *
+ * @return the operation type
+ */
+ Type type() {
+ return type;
+ }
+
+ /**
+ * Returns the service name of the service to which this operation belongs.
+ *
+ * @return the service name of the service to which this operation belongs
+ */
+ String service() {
+ return service;
+ }
+
+ /**
+ * Returns the operation name.
+ *
+ * @return the operation name
+ */
+ String name() {
+ return name;
+ }
+
+ /**
+ * Returns the operation method.
+ *
+ * @return the operation method
+ */
+ Method method() {
+ return method;
+ }
+
+ /**
+ * Returns the operation message subject.
+ *
+ * @return the operation message subject
+ */
+ MessageSubject subject() {
+ return subject;
+ }
+ }
+}