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.hadoop.hbase.procedure2; 20 21 import java.io.IOException; 22 import java.io.InputStream; 23 import java.io.OutputStream; 24 25 import org.apache.hadoop.hbase.classification.InterfaceAudience; 26 import org.apache.hadoop.hbase.classification.InterfaceStability; 27 import org.apache.hadoop.hbase.protobuf.generated.ProcedureProtos.SequentialProcedureData; 28 29 /** 30 * A SequentialProcedure describes one step in a procedure chain. 31 * -> Step 1 -> Step 2 -> Step 3 32 * 33 * The main difference from a base Procedure is that the execute() of a 34 * SequentialProcedure will be called only once, there will be no second 35 * execute() call once the child are finished. which means once the child 36 * of a SequentialProcedure are completed the SequentialProcedure is completed too. 37 */ 38 @InterfaceAudience.Private 39 @InterfaceStability.Evolving 40 public abstract class SequentialProcedure<TEnvironment> extends Procedure<TEnvironment> { 41 private boolean executed = false; 42 43 @Override doExecute(final TEnvironment env)44 protected Procedure[] doExecute(final TEnvironment env) 45 throws ProcedureYieldException, InterruptedException { 46 updateTimestamp(); 47 try { 48 Procedure[] children = !executed ? execute(env) : null; 49 executed = !executed; 50 return children; 51 } finally { 52 updateTimestamp(); 53 } 54 } 55 56 @Override doRollback(final TEnvironment env)57 protected void doRollback(final TEnvironment env) 58 throws IOException, InterruptedException { 59 updateTimestamp(); 60 if (executed) { 61 try { 62 rollback(env); 63 executed = !executed; 64 } finally { 65 updateTimestamp(); 66 } 67 } 68 } 69 70 @Override serializeStateData(final OutputStream stream)71 protected void serializeStateData(final OutputStream stream) throws IOException { 72 SequentialProcedureData.Builder data = SequentialProcedureData.newBuilder(); 73 data.setExecuted(executed); 74 data.build().writeDelimitedTo(stream); 75 } 76 77 @Override deserializeStateData(final InputStream stream)78 protected void deserializeStateData(final InputStream stream) throws IOException { 79 SequentialProcedureData data = SequentialProcedureData.parseDelimitedFrom(stream); 80 executed = data.getExecuted(); 81 } 82 } 83