1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | package org.apache.hadoop.hdfs.server.protocol; |
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19 | |
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20 | import java.io.*; |
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21 | |
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22 | import org.apache.hadoop.io.*; |
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23 | |
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24 | public abstract class DatanodeCommand implements Writable { |
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25 | static class Register extends DatanodeCommand { |
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26 | private Register() {super(DatanodeProtocol.DNA_REGISTER);} |
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27 | public void readFields(DataInput in) {} |
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28 | public void write(DataOutput out) {} |
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29 | } |
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30 | |
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31 | static class Finalize extends DatanodeCommand { |
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32 | private Finalize() {super(DatanodeProtocol.DNA_FINALIZE);} |
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33 | public void readFields(DataInput in) {} |
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34 | public void write(DataOutput out) {} |
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35 | } |
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36 | |
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37 | static { // register a ctor |
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38 | WritableFactories.setFactory(Register.class, |
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39 | new WritableFactory() { |
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40 | public Writable newInstance() {return new Register();} |
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41 | }); |
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42 | WritableFactories.setFactory(Finalize.class, |
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43 | new WritableFactory() { |
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44 | public Writable newInstance() {return new Finalize();} |
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45 | }); |
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46 | } |
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47 | |
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48 | public static final DatanodeCommand REGISTER = new Register(); |
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49 | public static final DatanodeCommand FINALIZE = new Finalize(); |
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50 | |
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51 | private int action; |
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52 | |
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53 | public DatanodeCommand() { |
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54 | this(DatanodeProtocol.DNA_UNKNOWN); |
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55 | } |
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56 | |
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57 | DatanodeCommand(int action) { |
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58 | this.action = action; |
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59 | } |
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60 | |
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61 | public int getAction() { |
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62 | return this.action; |
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63 | } |
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64 | |
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65 | /////////////////////////////////////////// |
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66 | // Writable |
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67 | /////////////////////////////////////////// |
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68 | public void write(DataOutput out) throws IOException { |
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69 | out.writeInt(this.action); |
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70 | } |
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71 | |
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72 | public void readFields(DataInput in) throws IOException { |
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73 | this.action = in.readInt(); |
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74 | } |
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75 | } |
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