1 | /* |
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2 | * NullContext.java |
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3 | * Licensed to the Apache Software Foundation (ASF) under one |
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4 | * or more contributor license agreements. See the NOTICE file |
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5 | * distributed with this work for additional information |
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6 | * regarding copyright ownership. The ASF licenses this file |
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7 | * to you under the Apache License, Version 2.0 (the |
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8 | * "License"); you may not use this file except in compliance |
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9 | * with the License. You may obtain a copy of the License at |
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10 | * |
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11 | * http://www.apache.org/licenses/LICENSE-2.0 |
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12 | * |
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13 | * Unless required by applicable law or agreed to in writing, software |
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14 | * distributed under the License is distributed on an "AS IS" BASIS, |
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15 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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16 | * See the License for the specific language governing permissions and |
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17 | * limitations under the License. |
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18 | */ |
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19 | |
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20 | package org.apache.hadoop.metrics.spi; |
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21 | |
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22 | /** |
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23 | * Null metrics context: a metrics context which does nothing. Used as the |
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24 | * default context, so that no performance data is emitted if no configuration |
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25 | * data is found. |
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26 | * |
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27 | */ |
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28 | public class NullContext extends AbstractMetricsContext { |
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29 | |
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30 | /** Creates a new instance of NullContext */ |
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31 | public NullContext() { |
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32 | } |
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33 | |
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34 | /** |
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35 | * Do-nothing version of startMonitoring |
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36 | */ |
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37 | public void startMonitoring() { |
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38 | } |
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39 | |
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40 | /** |
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41 | * Do-nothing version of emitRecord |
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42 | */ |
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43 | protected void emitRecord(String contextName, String recordName, |
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44 | OutputRecord outRec) |
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45 | {} |
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46 | |
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47 | /** |
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48 | * Do-nothing version of update |
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49 | */ |
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50 | protected void update(MetricsRecordImpl record) { |
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51 | } |
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52 | |
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53 | /** |
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54 | * Do-nothing version of remove |
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55 | */ |
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56 | protected void remove(MetricsRecordImpl record) { |
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57 | } |
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58 | } |
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