Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * 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 com.vaadin.server; import java.lang.reflect.Method; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import com.vaadin.shared.communication.MethodInvocation; import com.vaadin.shared.communication.ServerRpc; public class ServerRpcMethodInvocation extends MethodInvocation { private static final Map<String, Method> INVOCATION_METHOD_CACHE = new ConcurrentHashMap<>(128, 0.75f, 1); private final Method method; private final Class<? extends ServerRpc> interfaceClass; public ServerRpcMethodInvocation(String connectorId, Class<? extends ServerRpc> interfaceClass, String methodName, int parameterCount) { super(connectorId, interfaceClass.getName(), methodName); assert ServerRpc.class.isAssignableFrom(interfaceClass); this.interfaceClass = interfaceClass; method = findInvocationMethod(interfaceClass, methodName, parameterCount); } public Class<? extends ServerRpc> getInterfaceClass() { return interfaceClass; } public Method getMethod() { return method; } /** * Tries to find the method from the cache or alternatively by invoking * {@link #doFindInvocationMethod(Class, String, int)} and updating the * cache. * * @param targetType * @param methodName * @param parameterCount * @return */ private Method findInvocationMethod(Class<?> targetType, String methodName, int parameterCount) { // TODO currently only using method name and number of parameters as the // signature String signature = targetType.getName() + "." + methodName + "(" + parameterCount; Method invocationMethod = INVOCATION_METHOD_CACHE.get(signature); if (invocationMethod == null) { invocationMethod = doFindInvocationMethod(targetType, methodName, parameterCount); if (invocationMethod != null) { INVOCATION_METHOD_CACHE.put(signature, invocationMethod); } } if (invocationMethod == null) { throw new IllegalStateException("Can't find method " + methodName + " with " + parameterCount + " parameters in " + targetType.getName()); } return invocationMethod; } /** * Tries to find the method from the class by looping through available * methods. * * @param targetType * @param methodName * @param parameterCount * @return */ private Method doFindInvocationMethod(Class<?> targetType, String methodName, int parameterCount) { Method[] methods = targetType.getMethods(); for (Method method : methods) { Class<?>[] parameterTypes = method.getParameterTypes(); if (method.getName().equals(methodName) && parameterTypes.length == parameterCount) { return method; } } return null; } }