| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| CreateReducersApi |
|
| 1.0;1 | ||||
| CreateReducersApi$CreateReducerFunctionApi |
|
| 1.0;1 |
| 1 | /* | |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one | |
| 3 | * or more contributor license agreements. See the NOTICE file | |
| 4 | * distributed with this work for additional information | |
| 5 | * regarding copyright ownership. The ASF licenses this file | |
| 6 | * to you under the Apache License, Version 2.0 (the | |
| 7 | * "License"); you may not use this file except in compliance | |
| 8 | * with the License. You may obtain a copy of the License at | |
| 9 | * | |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 | |
| 11 | * | |
| 12 | * Unless required by applicable law or agreed to in writing, software | |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, | |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 15 | * See the License for the specific language governing permissions and | |
| 16 | * limitations under the License. | |
| 17 | */ | |
| 18 | package org.apache.giraph.block_app.framework.api; | |
| 19 | ||
| 20 | import org.apache.giraph.block_app.framework.piece.global_comm.ReducerHandle; | |
| 21 | import org.apache.giraph.reducers.ReduceOperation; | |
| 22 | import org.apache.hadoop.io.Writable; | |
| 23 | ||
| 24 | /** | |
| 25 | * Api for creating reducer handles. | |
| 26 | */ | |
| 27 | public interface CreateReducersApi extends BlockConfApi { | |
| 28 | ||
| 29 | /** | |
| 30 | * Create local reducer, returning a handle to it. | |
| 31 | * | |
| 32 | * Local reducer means that each worker thread has it's own local partially | |
| 33 | * reduced value, which are at the end reduced all together. | |
| 34 | * Preferable, unless it cannot be used, because all copies of the object | |
| 35 | * do not fit the memory. | |
| 36 | */ | |
| 37 | <S, R extends Writable> ReducerHandle<S, R> createLocalReducer( | |
| 38 | ReduceOperation<S, R> reduceOp); | |
| 39 | ||
| 40 | /** | |
| 41 | * Create local reducer, returning a handle to it. | |
| 42 | * | |
| 43 | * Local reducer means that each worker thread has it's own local partially | |
| 44 | * reduced value, which are at the end reduced all together. | |
| 45 | * Preferable, unless it cannot be used, because all copies of the object | |
| 46 | * do not fit the memory. | |
| 47 | */ | |
| 48 | <S, R extends Writable> ReducerHandle<S, R> createLocalReducer( | |
| 49 | ReduceOperation<S, R> reduceOp, R globalInitialValue); | |
| 50 | ||
| 51 | /** | |
| 52 | * Create global reducer, returning a handle to it. | |
| 53 | * | |
| 54 | * Global reducer means that there is only one value for each worker, | |
| 55 | * and each call to reduce will have to obtain a global lock, and incur | |
| 56 | * synchronization costs. | |
| 57 | * Use only when objects are so large, that having many copies cannot | |
| 58 | * fit into memory. | |
| 59 | */ | |
| 60 | <S, R extends Writable> ReducerHandle<S, R> createGlobalReducer( | |
| 61 | ReduceOperation<S, R> reduceOp); | |
| 62 | ||
| 63 | /** | |
| 64 | * Create global reducer, returning a handle to it. | |
| 65 | * | |
| 66 | * Global reducer means that there is only one value for each worker, | |
| 67 | * and each call to reduce will have to obtain a global lock, and incur | |
| 68 | * synchronization costs. | |
| 69 | * Use only when objects are so large, that having many copies cannot | |
| 70 | * fit into memory. | |
| 71 | */ | |
| 72 | <S, R extends Writable> ReducerHandle<S, R> createGlobalReducer( | |
| 73 | ReduceOperation<S, R> reduceOp, R globalInitialValue); | |
| 74 | ||
| 75 | /** | |
| 76 | * Function that creates a reducer - abstracting away whether it is | |
| 77 | * local or global reducer | |
| 78 | */ | |
| 79 | public interface CreateReducerFunctionApi { | |
| 80 | <S, R extends Writable> ReducerHandle<S, R> createReducer( | |
| 81 | ReduceOperation<S, R> reduceOp); | |
| 82 | } | |
| 83 | } |