001/** 002* Licensed to the Apache Software Foundation (ASF) under one 003* or more contributor license agreements. See the NOTICE file 004* distributed with this work for additional information 005* regarding copyright ownership. The ASF licenses this file 006* to you under the Apache License, Version 2.0 (the 007* "License"); you may not use this file except in compliance 008* with the License. You may obtain a copy of the License at 009* 010* http://www.apache.org/licenses/LICENSE-2.0 011* 012* Unless required by applicable law or agreed to in writing, software 013* distributed under the License is distributed on an "AS IS" BASIS, 014* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015* See the License for the specific language governing permissions and 016* limitations under the License. 017*/ 018 019package org.apache.hadoop.yarn.state; 020 021import org.apache.hadoop.classification.InterfaceAudience.Public; 022import org.apache.hadoop.classification.InterfaceStability.Evolving; 023 024/** 025 * Hook for Transition. 026 * Post state is decided by Transition hook. Post state must be one of the 027 * valid post states registered in StateMachine. 028 */ 029@Public 030@Evolving 031public interface MultipleArcTransition 032 <OPERAND, EVENT, STATE extends Enum<STATE>> { 033 034 /** 035 * Transition hook. 036 * @return the postState. Post state must be one of the 037 * valid post states registered in StateMachine. 038 * @param operand the entity attached to the FSM, whose internal 039 * state may change. 040 * @param event causal event 041 */ 042 public STATE transition(OPERAND operand, EVENT event); 043 044}