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 /** 21 * Function for accessing WorkerValue. 22 * 23 * Intentionally hidden from APIs, to allow usage only 24 * within PieceWithWorkerContext. 25 */ 26 public interface BlockWorkerValueAccessor { 27 /** 28 * Get global worker value. 29 * Value returned can be accessed from may threads, and so all 30 * accesses to it should be done in a thread-safe manner! 31 * 32 * This is the only place in Blocks Framework where you need 33 * to take care of concurrency. 34 */ 35 Object getWorkerValue(); 36 }