spork-master/src/org/apache/pig/impl/builtin/IdentityColumn.java
/*
 * 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.pig.impl.builtin;

import org.apache.pig.EvalFunc;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.logicalLayer.schema.Schema;


/**
 * Returns the input, used by DuplicateForEachColumnRewrite
 * to rewrite duplicate columns in ForEach. Not intended for 
 * external use
 */
public class IdentityColumn extends EvalFunc<Object> {

    @Override
    public Object exec(Tuple input) throws ExecException {
        return input.get(0);
    }

    @Override
    public Schema outputSchema(Schema input) {
        return input; 
    }

}
