/*
* 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.operators;
import java.util.HashMap;
import java.util.Map;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.functions.Function;
import org.apache.flink.api.common.operators.util.UserCodeWrapper;
/**
* Abstract superclass for all contracts that represent actual operators.
*
* @param <FT> Type of the user function
*/
@Internal
public abstract class AbstractUdfOperator<OUT, FT extends Function> extends Operator<OUT> {
/**
* The object or class containing the user function.
*/
protected final UserCodeWrapper<FT> userFunction;
/**
* The extra inputs which parameterize the user function.
*/
protected final Map<String, Operator<?>> broadcastInputs = new HashMap<>();
// --------------------------------------------------------------------------------------------
/**
* Creates a new abstract operator with the given name wrapping the given user function.
*
* @param function The wrapper object containing the user function.
* @param name The given name for the operator, used in plans, logs and progress messages.
*/
protected AbstractUdfOperator(UserCodeWrapper<FT> function, OperatorInformation<OUT> operatorInfo, String name) {
super(operatorInfo, name);
this.userFunction = function;
}
// --------------------------------------------------------------------------------------------
/**
* Gets the function that is held by this operator. The function is the actual implementation of the
* user code.
*
* This throws an exception if the pact does not contain an object but a class for the user
* code.
*
* @return The object with the user function for this operator.
*
* @see org.apache.flink.api.common.operators.Operator#getUserCodeWrapper()
*/
@Override
public UserCodeWrapper<FT> getUserCodeWrapper() {
return userFunction;
}
// --------------------------------------------------------------------------------------------
/**
* Returns the input, or null, if none is set.
*
* @return The broadcast input root operator.
*/
public Map<String, Operator<?>> getBroadcastInputs() {
return this.broadcastInputs;
}
/**
* Binds the result produced by a plan rooted at {@code root} to a variable
* used by the UDF wrapped in this operator.
*
* @param root The root of the plan producing this input.
*/
public void setBroadcastVariable(String name, Operator<?> root) {
if (name == null) {
throw new IllegalArgumentException("The broadcast input name may not be null.");
}
if (root == null) {
throw new IllegalArgumentException("The broadcast input root operator may not be null.");
}
this.broadcastInputs.put(name, root);
}
/**
* Clears all previous broadcast inputs and binds the given inputs as
* broadcast variables of this operator.
*
* @param inputs The {@code<name, root>} pairs to be set as broadcast inputs.
*/
public <T> void setBroadcastVariables(Map<String, Operator<T>> inputs) {
this.broadcastInputs.clear();
this.broadcastInputs.putAll(inputs);
}
// --------------------------------------------------------------------------------------------
/**
* Gets the number of inputs for this operator.
*
* @return The number of inputs for this operator.
*/
public abstract int getNumberOfInputs();
/**
* Gets the column numbers of the key fields in the input records for the given input.
*
* @return The column numbers of the key fields.
*/
public abstract int[] getKeyColumns(int inputNum);
// --------------------------------------------------------------------------------------------
/**
* Generic utility function that wraps a single class object into an array of that class type.
*
* @param <U> The type of the classes.
* @param clazz The class object to be wrapped.
* @return An array wrapping the class object.
*/
protected static <U> Class<U>[] asArray(Class<U> clazz) {
@SuppressWarnings("unchecked")
Class<U>[] array = new Class[] { clazz };
return array;
}
/**
* Generic utility function that returns an empty class array.
*
* @param <U> The type of the classes.
* @return An empty array of type <tt>Class<U></tt>.
*/
protected static <U> Class<U>[] emptyClassArray() {
@SuppressWarnings("unchecked")
Class<U>[] array = new Class[0];
return array;
}
}