org.apache.hadoop.ipc.ProtocolProxy Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.hadoop.ipc;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.HashSet;
/**
* a class wraps around a server's proxy,
* containing a list of its supported methods.
*
* A list of methods with a value of null indicates that the client and server
* have the same protocol.
*/
public class ProtocolProxy {
private Class protocol;
private T proxy;
private HashSet serverMethods = null;
private int methodsFingerprint = -1;
/**
* Constructor
*
* @param protocol protocol class
* @param proxy its proxy
* @param serverMethods a list of hash codes of the methods that it supports
* @throws ClassNotFoundException
*/
public ProtocolProxy(Class protocol, T proxy, int[] serverMethods) {
this.protocol = protocol;
this.proxy = proxy;
if (serverMethods != null) {
this.serverMethods = new HashSet(serverMethods.length);
for (int method : serverMethods) {
this.serverMethods.add(Integer.valueOf(method));
}
methodsFingerprint = ProtocolSignature.getFingerprint(serverMethods);
} else {
methodsFingerprint = ProtocolSignature.getFingerprint(protocol
.getMethods());
}
}
/*
* Get the proxy
*/
public T getProxy() {
return proxy;
}
/**
* Check if a method is supported by the server or not
*
* @param methodName a method's name in String format
* @param parameterTypes a method's parameter types
* @return true if the method is supported by the server
*/
public boolean isMethodSupported(String methodName,
Class... parameterTypes)
throws IOException {
if (serverMethods == null) { // client & server have the same protocol
return true;
}
Method method;
try {
method = protocol.getDeclaredMethod(methodName, parameterTypes);
} catch (SecurityException e) {
throw new IOException(e);
} catch (NoSuchMethodException e) {
throw new IOException(e);
}
return serverMethods.contains(
Integer.valueOf(ProtocolSignature.getFingerprint(method)));
}
public int getMethodsFingerprint() {
return methodsFingerprint;
}
}