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BAEL-203: Querying Couchbase with MapReduce Views

This commit is contained in:
Kevin Gilmore 2017-01-30 21:48:28 -06:00
parent 99e75746f3
commit e371bb9093
9 changed files with 492 additions and 0 deletions
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6
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/CouchbaseKeyGenerator.java Normal file
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package com.baeldung.couchbase.mapreduce;
public interface CouchbaseKeyGenerator<T> {
String generateKey(T t);
}

10
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/DuplicateKeyException.java Normal file
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package com.baeldung.couchbase.mapreduce;
@SuppressWarnings("serial")
public class DuplicateKeyException extends Exception {
public DuplicateKeyException(String s) {
super(s);
}
}

11
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/RandomUUIDGenerator.java Normal file
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package com.baeldung.couchbase.mapreduce;
import java.util.UUID;
public class RandomUUIDGenerator<T> implements CouchbaseKeyGenerator<T> {
@Override
public String generateKey(T t) {
return UUID.randomUUID().toString();
}
}

50
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/StudentGrade.java Normal file
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package com.baeldung.couchbase.mapreduce;
public class StudentGrade {
private String name;
private String course;
private Integer grade;
private Integer hours;
public StudentGrade() { }
public StudentGrade(String name, String course, Integer grade, Integer hours) {
this.name = name;
this.course = course;
this.grade = grade;
this.hours = hours;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public Integer getGrade() {
return grade;
}
public void setGrade(Integer grade) {
this.grade = grade;
}
public Integer getHours() {
return hours;
}
public void setHours(Integer hours) {
this.hours = hours;
}
}

9
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/StudentGradeKeyGenerator.java Normal file
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package com.baeldung.couchbase.mapreduce;
public class StudentGradeKeyGenerator implements CouchbaseKeyGenerator<StudentGrade> {
@Override
public String generateKey(StudentGrade g) {
return g.getName() + ":" + g.getCourse();
}
}

70
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/StudentGradeQueryBuilder.java Normal file
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package com.baeldung.couchbase.mapreduce;
import com.couchbase.client.deps.com.fasterxml.jackson.databind.ObjectMapper;
import com.couchbase.client.java.document.json.JsonArray;
import com.couchbase.client.java.view.ViewQuery;
public class StudentGradeQueryBuilder {
final ObjectMapper om = new ObjectMapper();
public ViewQuery findAll() {
return ViewQuery.from("studentGrades", "findByCourse");
}
public ViewQuery findByCourse(String course) {
return ViewQuery.from("studentGrades", "findByCourse")
.key(course);
}
public ViewQuery findByCourses(String... courses) {
return ViewQuery.from("studentGrades", "findByCourse")
.keys(JsonArray.from(courses));
}
public ViewQuery findByGradeInRange(int lower, int upper, boolean inclusiveEnd) {
return ViewQuery.from("studentGrades", "findByGrade")
.startKey(lower)
.endKey(upper)
.inclusiveEnd(inclusiveEnd);
}
public ViewQuery findByGradeLessThan(int upper) {
return ViewQuery.from("studentGrades", "findByGrade")
.endKey(upper)
.inclusiveEnd(false);
}
public ViewQuery findByGradeGreaterThan(int lower) {
return ViewQuery.from("studentGrades", "findByGrade")
.startKey(lower);
}
public ViewQuery findByCourseAndGradeInRange(String course, int minGrade, int maxGrade, boolean inclusiveEnd) {
return ViewQuery.from("studentGrades", "findByCourseAndGrade")
.startKey(JsonArray.from(course, minGrade))
.endKey(JsonArray.from(course, maxGrade))
.inclusiveEnd(inclusiveEnd);
}
public ViewQuery findTopGradesByCourse(String course, int limit) {
return ViewQuery.from("studentGrades", "findByCourseAndGrade")
.startKey(JsonArray.from(course, 100))
.endKey(JsonArray.from(course, 0))
.inclusiveEnd(true)
.descending()
.limit(limit);
}
public ViewQuery countStudentsByCourse() {
return ViewQuery.from("studentGrades", "countStudentsByCourse")
.reduce()
.groupLevel(1);
}
public ViewQuery sumCreditsByStudent() {
return ViewQuery.from("studentGrades", "sumCreditsByStudent")
.reduce()
.groupLevel(1);
}
}

169
couchbase-sdk/src/main/java/com/baeldung/couchbase/mapreduce/StudentGradeService.java Normal file
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package com.baeldung.couchbase.mapreduce;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import com.couchbase.client.deps.com.fasterxml.jackson.databind.ObjectMapper;
import com.couchbase.client.java.Bucket;
import com.couchbase.client.java.CouchbaseCluster;
import com.couchbase.client.java.document.JsonDocument;
import com.couchbase.client.java.document.json.JsonArray;
import com.couchbase.client.java.document.json.JsonObject;
import com.couchbase.client.java.view.ViewQuery;
import com.couchbase.client.java.view.ViewResult;
import com.couchbase.client.java.view.ViewRow;
public class StudentGradeService {
final CouchbaseKeyGenerator<StudentGrade> keyGenerator;
final CouchbaseCluster cluster;
final Bucket bucket;
final ObjectMapper om = new ObjectMapper();
final StudentGradeQueryBuilder queryBuilder;
public StudentGradeService(CouchbaseKeyGenerator<StudentGrade> keyGenerator) {
this.keyGenerator = keyGenerator;
this.queryBuilder = new StudentGradeQueryBuilder();
cluster = CouchbaseCluster.create("127.0.0.1");
bucket = cluster.openBucket("baeldung-tutorial");
}
public String insert(StudentGrade studentGrade) throws DuplicateKeyException {
String id = keyGenerator.generateKey(studentGrade);
if(bucket.exists(id)) {
throw new DuplicateKeyException("document already exists with key " + id);
}
JsonObject content = JsonObject.empty()
.put("type", "StudentGrade")
.put("name", studentGrade.getName())
.put("course", studentGrade.getCourse())
.put("grade", studentGrade.getGrade())
.put("hours", studentGrade.getHours());
JsonDocument doc = JsonDocument.create(id, content);
bucket.insert(doc);
return id;
}
public List<JsonDocument> findAll() {
ViewQuery query = queryBuilder.findAll();
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
private List<JsonDocument> extractDocuments(ViewResult result) {
List<JsonDocument> docs = new ArrayList<>();
for(ViewRow row : result.allRows()) {
JsonDocument doc = row.document();
docs.add(doc);
}
return docs;
}
public List<JsonDocument> findByCourse(String course) {
ViewQuery query = queryBuilder.findByCourse(course);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findByCourses(String... courses) {
ViewQuery query = queryBuilder.findByCourses(courses);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findByGradeInRange(int lower, int upper, boolean inclusiveEnd) {
ViewQuery query = queryBuilder.findByGradeInRange(lower, upper, inclusiveEnd);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findByGradeLessThan(int upper) {
ViewQuery query = queryBuilder.findByGradeLessThan(upper);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findByGradeGreaterThan(int lower) {
ViewQuery query = queryBuilder.findByGradeGreaterThan(lower);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findByCourseAndGradeInRange(String course, int minGrade, int maxGrade, boolean inclusiveEnd) {
ViewQuery query = queryBuilder.findByCourseAndGradeInRange(course, minGrade, maxGrade, inclusiveEnd);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public List<JsonDocument> findTopGradesByCourse(String course, int limit) {
ViewQuery query = queryBuilder.findTopGradesByCourse(course, limit);
ViewResult result = bucket.query(query);
return extractDocuments(result);
}
public Map<String, Long> countStudentsByCourse() {
ViewQuery query = ViewQuery.from("studentGrades", "countStudentsByCourse")
.reduce()
.groupLevel(1);
ViewResult result = bucket.query(query);
Map<String, Long> numStudentsByCourse = new HashMap<>();
for(ViewRow row : result.allRows()) {
JsonArray keyArray = (JsonArray) row.key();
String course = keyArray.getString(0);
long count = Long.valueOf(row.value().toString());
numStudentsByCourse.put(course, count);
}
return numStudentsByCourse;
}
public Map<String, Long> sumCreditHoursByStudent() {
ViewQuery query = ViewQuery.from("studentGrades", "sumHoursByStudent")
.reduce()
.groupLevel(1);
ViewResult result = bucket.query(query);
Map<String, Long> creditHoursByStudent = new HashMap<>();
for(ViewRow row : result.allRows()) {
String course = (String) row.key();
long sum = Long.valueOf(row.value().toString());
creditHoursByStudent.put(course, sum);
}
return creditHoursByStudent;
}
public Map<String, Long> sumGradePointsByStudent() {
ViewQuery query = ViewQuery.from("studentGrades", "sumGradePointsByStudent")
.reduce()
.groupLevel(1);
ViewResult result = bucket.query(query);
Map<String, Long> gradePointsByStudent = new HashMap<>();
for(ViewRow row : result.allRows()) {
String course = (String) row.key();
long sum = Long.valueOf(row.value().toString());
gradePointsByStudent.put(course, sum);
}
return gradePointsByStudent;
}
public Map<String, Float> calculateGpaByStudent() {
Map<String, Long> creditHoursByStudent = sumCreditHoursByStudent();
Map<String, Long> gradePointsByStudent = sumGradePointsByStudent();
Map<String, Float> result = new HashMap<>();
for(Entry<String, Long> creditHoursEntry : creditHoursByStudent.entrySet()) {
String name = creditHoursEntry.getKey();
long totalHours = creditHoursEntry.getValue();
long totalGradePoints = gradePointsByStudent.get(name);
result.put(name, ((float) totalGradePoints / totalHours));
}
return result;
}
}

150
couchbase-sdk/src/test/java/com/baeldung/couchbase/mapreduce/StudentGradeServiceIntegrationTest.java Normal file
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package com.baeldung.couchbase.mapreduce;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.junit.BeforeClass;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.couchbase.client.java.document.JsonDocument;
import com.couchbase.client.java.view.ViewResult;
import com.couchbase.client.java.view.ViewRow;
public class StudentGradeServiceIntegrationTest {
private static final Logger logger = LoggerFactory.getLogger(StudentGradeServiceIntegrationTest.class);
static StudentGradeService studentGradeService;
static Set<String> gradeIds = new HashSet<>();
@BeforeClass
public static void setUpBeforeClass() throws Exception {
studentGradeService = new StudentGradeService(new StudentGradeKeyGenerator());
insertStudentGrade(new StudentGrade("John Doe", "History", 80, 3));
insertStudentGrade(new StudentGrade("Jane Doe", "History", 89, 3));
insertStudentGrade(new StudentGrade("Bob Smith", "History", 90, 3));
insertStudentGrade(new StudentGrade("Mary Jones", "History", 92, 3));
insertStudentGrade(new StudentGrade("Jane Doe", "Math", 59, 3));
insertStudentGrade(new StudentGrade("Bob Smith", "Math", 91, 3));
insertStudentGrade(new StudentGrade("Mary Jones", "Math", 86, 3));
insertStudentGrade(new StudentGrade("John Doe", "Science", 85, 4));
insertStudentGrade(new StudentGrade("Bob Smith", "Science", 97, 4));
insertStudentGrade(new StudentGrade("Mary Jones", "Science", 84, 4));
}
private static void insertStudentGrade(StudentGrade studentGrade) {
try {
String id = studentGradeService.insert(studentGrade);
gradeIds.add(id);
} catch (DuplicateKeyException e) {
}
}
@Test
public final void whenFindAll_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findAll();
printDocuments(docs);
}
@Test
public final void whenFindByCourse_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByCourse("History");
printDocuments(docs);
}
@Test
public final void whenFindByCourses_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByCourses("History", "Science");
printDocuments(docs);
}
@Test
public final void whenFindByGradeInRange_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByGradeInRange(80, 89, true);
printDocuments(docs);
}
@Test
public final void whenFindByGradeLessThan_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByGradeLessThan(60);
printDocuments(docs);
}
@Test
public final void whenFindByGradeGreaterThan_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByGradeGreaterThan(90);
printDocuments(docs);
}
@Test
public final void whenFindByCourseAndGradeInRange_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findByCourseAndGradeInRange("Math", 80, 89, true);
printDocuments(docs);
}
@Test
public final void whenFindTopGradesByCourse_thenSuccess() {
List<JsonDocument> docs = studentGradeService.findTopGradesByCourse("Science", 2);
printDocuments(docs);
}
@Test
public final void whenCountStudentsByCourse_thenSuccess() {
Map<String, Long> map = studentGradeService.countStudentsByCourse();
printMap(map);
}
@Test
public final void whenSumCreditHoursByStudent_thenSuccess() {
Map<String, Long> map = studentGradeService.sumCreditHoursByStudent();
printMap(map);
}
@Test
public final void whenSumGradePointsByStudent_thenSuccess() {
Map<String, Long> map = studentGradeService.sumGradePointsByStudent();
printMap(map);
}
@Test
public final void whenCalculateGpaByStudent_thenSuccess() {
Map<String, Float> map = studentGradeService.calculateGpaByStudent();
printGpaMap(map);
}
private void printMap(Map<String, Long> map) {
for(Map.Entry<String, Long> entry : map.entrySet()) {
logger.info(entry.getKey() + "=" + entry.getValue());
}
}
private void printGpaMap(Map<String, Float> map) {
for(Map.Entry<String, Float> entry : map.entrySet()) {
logger.info(entry.getKey() + "=" + entry.getValue());
}
}
private void printDocuments(List<JsonDocument> docs) {
for(JsonDocument doc : docs) {
String key = doc.id();
logger.info(key + " = " + doc.content().toString());
}
}
private void printViewResultDocuments(ViewResult result) {
for(ViewRow row : result.allRows()) {
JsonDocument doc = row.document();
String key = doc.id();
logger.info(key + "=" + doc.content().toString());
}
}
private void printViewResultRows(ViewResult result) {
for(ViewRow row : result.allRows()) {
logger.info(row.toString());
}
}
}

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couchbase-sdk/src/test/resources/logback.xml Normal file
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<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>web - %date [%thread] %-5level %logger{36} - %message%n
</pattern>
</encoder>
</appender>
<logger name="org.springframework" level="WARN" />
<logger name="com.baeldung" level="DEBUG" />
<root level="INFO">
<appender-ref ref="STDOUT" />
</root>
</configuration>