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 19 package org.apache.giraph.mapping; 20 21 import org.apache.giraph.conf.ImmutableClassesGiraphConfigurable; 22 import org.apache.hadoop.io.Writable; 23 import org.apache.hadoop.io.WritableComparable; 24 25 /** 26 * MappingStore used to store the vertexId - target map supplied by user 27 * Methods implemented in this class need to be thread safe 28 * 29 * @param <I> vertexId type 30 * @param <B> mappingTarget type 31 */ 32 public interface MappingStore<I extends WritableComparable, B extends Writable> 33 extends ImmutableClassesGiraphConfigurable<I, Writable, Writable> { 34 35 /** 36 * Must be called before anything else can be done 37 * on this instance 38 */ 39 void initialize(); 40 41 /** 42 * Add an entry to the mapping store 43 * 44 * @param vertexId vertexId 45 * @param target target 46 */ 47 void addEntry(I vertexId, B target); 48 49 /** 50 * Get target for given vertexId 51 * 52 * @param vertexId vertexId 53 * @param target instance to use for storing target information 54 * @return target instance 55 */ 56 B getTarget(I vertexId, B target); 57 58 /** 59 * Operations to perform after adding entries 60 * to the mapping store 61 */ 62 void postFilling(); 63 64 /** 65 * Get stats about the MappingStore 66 * 67 * @return numEntries 68 */ 69 long getStats(); 70 }