| /** |
| * 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.tez.engine.api; |
| |
| import java.util.List; |
| |
| /** |
| * Represents an input through which a TezProcessor receives data on an edge. |
| * </p> |
| * |
| * <code>Input</code> classes must have a 0 argument public constructor for Tez |
| * to construct the <code>Input</code>. Tez will take care of initializing and |
| * closing the Input after a {@link Processor} completes. </p> |
| */ |
| public interface Input { |
| |
| /** |
| * Initializes the <code>Input</code>. |
| * |
| * @param inputContext |
| * the {@link TezInputContext} |
| * @return |
| * @throws Exception |
| * if an error occurs |
| */ |
| public List<Event> initialize(TezInputContext inputContext) |
| throws Exception; |
| |
| /** |
| * Gets an instance of the {@link Reader} for this <code>Output</code> |
| * |
| * @return |
| * @throws Exception |
| * if an error occurs |
| */ |
| public Reader getReader() throws Exception; |
| |
| /** |
| * Handles user and system generated {@link Events}s, which typically carry |
| * information such as an output being available on the previous vertex. |
| * |
| * @param inputEvents |
| * the list of {@link Event}s |
| */ |
| public void handleEvents(List<Event> inputEvents); |
| |
| /** |
| * Closes the <code>Input</code> |
| * |
| * @return |
| * @throws Exception |
| * if an error occurs |
| */ |
| public List<Event> close() throws Exception; |
| } |