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    
019    package org.apache.hadoop.yarn.state;
020    
021    import org.apache.hadoop.classification.InterfaceAudience.Public;
022    import org.apache.hadoop.classification.InterfaceStability.Evolving;
023    
024    /**
025     * Hook for Transition. This lead to state machine to move to 
026     * the post state as registered in the state machine.
027     */
028    @Public
029    @Evolving
030    public interface SingleArcTransition<OPERAND, EVENT> {
031      /**
032       * Transition hook.
033       * 
034       * @param operand the entity attached to the FSM, whose internal 
035       *                state may change.
036       * @param event causal event
037       */
038      public void transition(OPERAND operand, EVENT event);
039    
040    }