/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.examples;
import static org.junit.Assert.assertEquals;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.TreeMap;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.ToolRunner;
import org.junit.Before;
import org.junit.Test;
public class TestWordStats {
private final static String INPUT = "src/test/java/org/apache/hadoop/examples/pi/math";
private final static String MEAN_OUTPUT = "build/data/mean_output";
private final static String MEDIAN_OUTPUT = "build/data/median_output";
private final static String STDDEV_OUTPUT = "build/data/stddev_output";
/**
* Modified internal test class that is designed to read all the files in the
* input directory, and find the standard deviation between all of the word
* lengths.
*/
public static class WordStdDevReader {
private long wordsRead = 0;
private long wordLengthsRead = 0;
private long wordLengthsReadSquared = 0;
public WordStdDevReader() {
}
public double read(String path) throws IOException {
FileSystem fs = FileSystem.get(new Configuration());
FileStatus[] files = fs.listStatus(new Path(path));
for (FileStatus fileStat : files) {
if (!fileStat.isFile())
continue;
BufferedReader br = null;
try {
br = new BufferedReader(new InputStreamReader(fs.open(fileStat.getPath())));
String line;
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
String word;
while (st.hasMoreTokens()) {
word = st.nextToken();
this.wordsRead++;
this.wordLengthsRead += word.length();
this.wordLengthsReadSquared += (long) Math.pow(word.length(), 2.0);
}
}
} catch (IOException e) {
System.out.println("Output could not be read!");
throw e;
} finally {
br.close();
}
}
double mean = (((double) this.wordLengthsRead) / ((double) this.wordsRead));
mean = Math.pow(mean, 2.0);
double term = (((double) this.wordLengthsReadSquared / ((double) this.wordsRead)));
double stddev = Math.sqrt((term - mean));
return stddev;
}
}
/**
* Modified internal test class that is designed to read all the files in the
* input directory, and find the median length of all the words.
*/
public static class WordMedianReader {
private long wordsRead = 0;
private TreeMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
public WordMedianReader() {
}
public double read(String path) throws IOException {
FileSystem fs = FileSystem.get(new Configuration());
FileStatus[] files = fs.listStatus(new Path(path));
int num = 0;
for (FileStatus fileStat : files) {
if (!fileStat.isFile())
continue;
BufferedReader br = null;
try {
br = new BufferedReader(new InputStreamReader(fs.open(fileStat.getPath())));
String line;
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
String word;
while (st.hasMoreTokens()) {
word = st.nextToken();
this.wordsRead++;
if (this.map.get(word.length()) == null) {
this.map.put(word.length(), 1);
} else {
int count = this.map.get(word.length());
this.map.put(word.length(), count + 1);
}
}
}
} catch (IOException e) {
System.out.println("Output could not be read!");
throw e;
} finally {
br.close();
}
}
int medianIndex1 = (int) Math.ceil((this.wordsRead / 2.0));
int medianIndex2 = (int) Math.floor((this.wordsRead / 2.0));
for (Integer key : this.map.navigableKeySet()) {
int prevNum = num;
num += this.map.get(key);
if (medianIndex2 >= prevNum && medianIndex1 <= num) {
return key;
} else if (medianIndex2 >= prevNum && medianIndex1 < num) {
Integer nextCurrLen = this.map.navigableKeySet().iterator().next();
double median = (key + nextCurrLen) / 2.0;
return median;
}
}
return -1;
}
}
/**
* Modified internal test class that is designed to read all the files in the
* input directory, and find the mean length of all the words.
*/
public static class WordMeanReader {
private long wordsRead = 0;
private long wordLengthsRead = 0;
public WordMeanReader() {
}
public double read(String path) throws IOException {
FileSystem fs = FileSystem.get(new Configuration());
FileStatus[] files = fs.listStatus(new Path(path));
for (FileStatus fileStat : files) {
if (!fileStat.isFile())
continue;
BufferedReader br = null;
try {
br = new BufferedReader(new InputStreamReader(fs.open(fileStat.getPath())));
String line;
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
String word;
while (st.hasMoreTokens()) {
word = st.nextToken();
this.wordsRead++;
this.wordLengthsRead += word.length();
}
}
} catch (IOException e) {
System.out.println("Output could not be read!");
throw e;
} finally {
br.close();
}
}
double mean = (((double) this.wordLengthsRead) / ((double) this.wordsRead));
return mean;
}
}
/**
* Internal class designed to delete the output directory. Meant solely for
* use before and after the test is run; this is so next iterations of the
* test do not encounter a "file already exists" error.
*
* @param dir
* The directory to delete.
* @return Returns whether the deletion was successful or not.
*/
public static boolean deleteDir(File dir) {
if (dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
System.out.println("Could not delete directory after test!");
return false;
}
}
}
// The directory is now empty so delete it
return dir.delete();
}
@Before public void setup() throws Exception {
deleteDir(new File(MEAN_OUTPUT));
deleteDir(new File(MEDIAN_OUTPUT));
deleteDir(new File(STDDEV_OUTPUT));
}
@Test public void testGetTheMean() throws Exception {
String args[] = new String[2];
args[0] = INPUT;
args[1] = MEAN_OUTPUT;
WordMean wm = new WordMean();
ToolRunner.run(new Configuration(), wm, args);
double mean = wm.getMean();
// outputs MUST match
WordMeanReader wr = new WordMeanReader();
assertEquals(mean, wr.read(INPUT), 0.0);
}
@Test public void testGetTheMedian() throws Exception {
String args[] = new String[2];
args[0] = INPUT;
args[1] = MEDIAN_OUTPUT;
WordMedian wm = new WordMedian();
ToolRunner.run(new Configuration(), wm, args);
double median = wm.getMedian();
// outputs MUST match
WordMedianReader wr = new WordMedianReader();
assertEquals(median, wr.read(INPUT), 0.0);
}
@Test public void testGetTheStandardDeviation() throws Exception {
String args[] = new String[2];
args[0] = INPUT;
args[1] = STDDEV_OUTPUT;
WordStandardDeviation wsd = new WordStandardDeviation();
ToolRunner.run(new Configuration(), wsd, args);
double stddev = wsd.getStandardDeviation();
// outputs MUST match
WordStdDevReader wr = new WordStdDevReader();
assertEquals(stddev, wr.read(INPUT), 0.0);
}
}