| /* |
| * 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; |
| |
| import java.io.IOException; |
| |
| import org.apache.pig.Accumulator; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.data.Tuple; |
| |
| /** |
| * This class is used to provide a free implementation of the EvalFunc exec function given |
| * implementation of the Accumulator interface. Instead of having to provide a redundant |
| * implementation, this provides the base exec function for free, given that the methods |
| * associated with the Accumulator interface are implemented. For information on how to |
| * implement Accumulator, see {@link Accumulator}. |
| */ |
| public abstract class AccumulatorEvalFunc<T> extends EvalFunc<T> implements Accumulator<T> { |
| |
| @Override |
| public abstract void accumulate(Tuple b) throws IOException; |
| |
| @Override |
| public abstract void cleanup(); |
| |
| @Override |
| public abstract T getValue(); |
| |
| @Override |
| public T exec(Tuple input) throws IOException { |
| accumulate(input); |
| T result = getValue(); |
| cleanup(); |
| return result; |
| } |
| |
| } |