/*
 * 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.java.operators;

import org.apache.flink.annotation.Public;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.DataSet;

/**
 * Base class for operations that operates on a single input data set.
 * 
 * @param <IN> The data type of the input data set.
 * @param <OUT> The data type of the returned data set.
 */
@Public
public abstract class SingleInputOperator<IN, OUT, O extends SingleInputOperator<IN, OUT, O>> extends Operator<OUT, O> {
	
	private final DataSet<IN> input;
	
	
	protected SingleInputOperator(DataSet<IN> input, TypeInformation<OUT> resultType) {
		super(input.getExecutionEnvironment(), resultType);
		this.input = input;
	}
	
	/**
	 * Gets the data set that this operation uses as its input.
	 * 
	 * @return The data set that this operation uses as its input.
	 */
	public DataSet<IN> getInput() {
		return this.input;
	}
	
	/**
	 * Gets the type information of the data type of the input data set.
	 * This method returns equivalent information as {@code getInput().getType()}.
	 * 
	 * @return The input data type.
	 */
	public TypeInformation<IN> getInputType() {
		return this.input.getType();
	}
	
	/**
	 * Translates this operation to a data flow operator of the common data flow API.
	 * 
	 * @param input The data flow operator that produces this operation's input data.
	 * @return The translated data flow operator.
	 */
	protected abstract org.apache.flink.api.common.operators.Operator<OUT> translateToDataFlow(
			org.apache.flink.api.common.operators.Operator<IN> input);
	
}