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 | |
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19 | package org.apache.hadoop.io; |
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20 | |
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21 | import org.apache.hadoop.conf.Configuration; |
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22 | import org.apache.hadoop.fs.FileSystem; |
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23 | import org.apache.hadoop.fs.Path; |
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24 | |
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25 | import junit.framework.TestCase; |
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26 | |
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27 | public class TestBloomMapFile extends TestCase { |
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28 | private static Configuration conf = new Configuration(); |
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29 | |
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30 | public void testMembershipTest() throws Exception { |
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31 | // write the file |
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32 | Path dirName = new Path(System.getProperty("test.build.data",".") + |
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33 | getName() + ".bloommapfile"); |
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34 | FileSystem fs = FileSystem.getLocal(conf); |
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35 | Path qualifiedDirName = fs.makeQualified(dirName); |
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36 | conf.setInt("io.mapfile.bloom.size", 2048); |
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37 | BloomMapFile.Writer writer = new BloomMapFile.Writer(conf, fs, |
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38 | qualifiedDirName.toString(), IntWritable.class, Text.class); |
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39 | IntWritable key = new IntWritable(); |
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40 | Text value = new Text(); |
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41 | for (int i = 0; i < 2000; i += 2) { |
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42 | key.set(i); |
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43 | value.set("00" + i); |
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44 | writer.append(key, value); |
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45 | } |
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46 | writer.close(); |
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47 | |
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48 | BloomMapFile.Reader reader = new BloomMapFile.Reader(fs, |
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49 | qualifiedDirName.toString(), conf); |
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50 | // check false positives rate |
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51 | int falsePos = 0; |
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52 | int falseNeg = 0; |
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53 | for (int i = 0; i < 2000; i++) { |
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54 | key.set(i); |
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55 | boolean exists = reader.probablyHasKey(key); |
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56 | if (i % 2 == 0) { |
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57 | if (!exists) falseNeg++; |
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58 | } else { |
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59 | if (exists) falsePos++; |
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60 | } |
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61 | } |
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62 | reader.close(); |
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63 | fs.delete(qualifiedDirName, true); |
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64 | System.out.println("False negatives: " + falseNeg); |
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65 | assertEquals(0, falseNeg); |
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66 | System.out.println("False positives: " + falsePos); |
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67 | assertTrue(falsePos < 2); |
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68 | } |
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69 | |
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70 | } |
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