/*
* 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.flink.api.common.functions.util;
import java.lang.reflect.Method;
import org.apache.flink.api.common.functions.Function;
import org.apache.flink.api.common.functions.RichFunction;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.configuration.Configuration;
public class FunctionUtils {
public static void openFunction (Function function, Configuration parameters) throws Exception{
if (function instanceof RichFunction) {
RichFunction richFunction = (RichFunction) function;
richFunction.open (parameters);
}
}
public static void closeFunction (Function function) throws Exception{
if (function instanceof RichFunction) {
RichFunction richFunction = (RichFunction) function;
richFunction.close ();
}
}
public static void setFunctionRuntimeContext (Function function, RuntimeContext context){
if (function instanceof RichFunction) {
RichFunction richFunction = (RichFunction) function;
richFunction.setRuntimeContext(context);
}
}
public static RuntimeContext getFunctionRuntimeContext (Function function, RuntimeContext defaultContext){
if (function instanceof RichFunction) {
RichFunction richFunction = (RichFunction) function;
return richFunction.getRuntimeContext();
}
else {
return defaultContext;
}
}
public static Method checkAndExtractLambdaMethod(Function function) {
try {
// get serialized lambda
Object serializedLambda = null;
for (Class<?> clazz = function.getClass(); clazz != null; clazz = clazz.getSuperclass()) {
try {
Method replaceMethod = clazz.getDeclaredMethod("writeReplace");
replaceMethod.setAccessible(true);
Object serialVersion = replaceMethod.invoke(function);
// check if class is a lambda function
if (serialVersion.getClass().getName().equals("java.lang.invoke.SerializedLambda")) {
// check if SerializedLambda class is present
try {
Class.forName("java.lang.invoke.SerializedLambda");
}
catch (Exception e) {
throw new UnsupportedOperationException("User code tries to use lambdas, but framework is running with a Java version < 8");
}
serializedLambda = serialVersion;
break;
}
}
catch (NoSuchMethodException e) {
// thrown if the method is not there. fall through the loop
}
}
// not a lambda method -> return null
if (serializedLambda == null) {
return null;
}
// find lambda method
Method implClassMethod = serializedLambda.getClass().getDeclaredMethod("getImplClass");
Method implMethodNameMethod = serializedLambda.getClass().getDeclaredMethod("getImplMethodName");
String className = (String) implClassMethod.invoke(serializedLambda);
String methodName = (String) implMethodNameMethod.invoke(serializedLambda);
Class<?> implClass = Class.forName(className.replace('/', '.'), true, Thread.currentThread().getContextClassLoader());
Method[] methods = implClass.getDeclaredMethods();
Method parameterizedMethod = null;
for (Method method : methods) {
if(method.getName().equals(methodName)) {
if(parameterizedMethod != null) {
// It is very unlikely that a class contains multiple e.g. "lambda$2()" but its possible
// Actually, the signature need to be checked, but this is very complex
throw new Exception("Lambda method name is not unique.");
}
else {
parameterizedMethod = method;
}
}
}
if (parameterizedMethod == null) {
throw new Exception("No lambda method found.");
}
return parameterizedMethod;
}
catch (Exception e) {
throw new RuntimeException("Could not extract lambda method out of function: " + e.getClass().getSimpleName() + " - " + e.getMessage(), e);
}
}
}