Merge remote-tracking branch 'upstream/master'

This commit is contained in:
pazis
2019-08-23 21:03:01 +00:00
371 changed files with 3352 additions and 780 deletions
@@ -4,7 +4,7 @@ import org.apache.commons.lang3.StringUtils;
public class PrintTriangleExamples {
public static String printARightAngledTriangle(int N) {
public static String printARightTriangle(int N) {
StringBuilder result = new StringBuilder();
for (int r = 1; r <= N; r++) {
for (int j = 1; j <= r; j++) {
@@ -29,6 +29,17 @@ public class PrintTriangleExamples {
return result.toString();
}
public static String printAnIsoscelesTriangleUsingStringUtils(int N) {
StringBuilder result = new StringBuilder();
for (int r = 1; r <= N; r++) {
result.append(StringUtils.repeat(' ', N - r));
result.append(StringUtils.repeat('*', 2 * r - 1));
result.append(System.lineSeparator());
}
return result.toString();
}
public static String printAnIsoscelesTriangleUsingSubstring(int N) {
StringBuilder result = new StringBuilder();
String helperString = StringUtils.repeat(' ', N - 1) + StringUtils.repeat('*', N * 2 - 1);
@@ -41,8 +52,9 @@ public class PrintTriangleExamples {
}
public static void main(String[] args) {
System.out.println(printARightAngledTriangle(5));
System.out.println(printARightTriangle(5));
System.out.println(printAnIsoscelesTriangle(5));
System.out.println(printAnIsoscelesTriangleUsingStringUtils(5));
System.out.println(printAnIsoscelesTriangleUsingSubstring(5));
}
@@ -9,9 +9,9 @@ import static org.junit.Assert.assertEquals;
@RunWith(JUnitParamsRunner.class)
public class PrintTriangleExamplesUnitTest {
private static Object[][] rightAngledTriangles() {
String expected0 = "";
private static Object[][] rightTriangles() {
String expected0 = "";
String expected2 = "*" + System.lineSeparator()
+ "**" + System.lineSeparator();
@@ -39,9 +39,9 @@ public class PrintTriangleExamplesUnitTest {
}
@Test
@Parameters(method = "rightAngledTriangles")
public void whenPrintARightAngledTriangleIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) {
String actual = PrintTriangleExamples.printARightAngledTriangle(nrOfRows);
@Parameters(method = "rightTriangles")
public void whenPrintARightTriangleIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) {
String actual = PrintTriangleExamples.printARightTriangle(nrOfRows);
assertEquals(expected, actual);
}
@@ -81,6 +81,14 @@ public class PrintTriangleExamplesUnitTest {
assertEquals(expected, actual);
}
@Test
@Parameters(method = "isoscelesTriangles")
public void whenPrintAnIsoscelesTriangleUsingStringUtilsIsCalled_ThenTheCorrectStringIsReturned(int nrOfRows, String expected) {
String actual = PrintTriangleExamples.printAnIsoscelesTriangleUsingStringUtils(nrOfRows);
assertEquals(expected, actual);
}
@Test
@Parameters(method = "isoscelesTriangles")
@@ -1,4 +1,4 @@
package com.baeldung.algorithms.stringsortingbynumber;
package com.baeldung.algorithms.sort.bynumber;
import java.util.Comparator;
@@ -1,6 +1,6 @@
package com.baeldung.algorithms.stringsortingbynumber;
package com.baeldung.algorithms.sort.bynumber;
import com.baeldung.algorithms.stringsortingbynumber.NaturalOrderComparators;
import com.baeldung.algorithms.sort.bynumber.NaturalOrderComparators;
import org.junit.Test;
import java.util.ArrayList;
+150
View File
@@ -0,0 +1,150 @@
5.1,3.5,1.4,0.2,Iris-setosa
4.9,3.0,1.4,0.2,Iris-setosa
4.7,3.2,1.3,0.2,Iris-setosa
4.6,3.1,1.5,0.2,Iris-setosa
5.0,3.6,1.4,0.2,Iris-setosa
5.4,3.9,1.7,0.4,Iris-setosa
4.6,3.4,1.4,0.3,Iris-setosa
5.0,3.4,1.5,0.2,Iris-setosa
4.4,2.9,1.4,0.2,Iris-setosa
4.9,3.1,1.5,0.1,Iris-setosa
5.4,3.7,1.5,0.2,Iris-setosa
4.8,3.4,1.6,0.2,Iris-setosa
4.8,3.0,1.4,0.1,Iris-setosa
4.3,3.0,1.1,0.1,Iris-setosa
5.8,4.0,1.2,0.2,Iris-setosa
5.7,4.4,1.5,0.4,Iris-setosa
5.4,3.9,1.3,0.4,Iris-setosa
5.1,3.5,1.4,0.3,Iris-setosa
5.7,3.8,1.7,0.3,Iris-setosa
5.1,3.8,1.5,0.3,Iris-setosa
5.4,3.4,1.7,0.2,Iris-setosa
5.1,3.7,1.5,0.4,Iris-setosa
4.6,3.6,1.0,0.2,Iris-setosa
5.1,3.3,1.7,0.5,Iris-setosa
4.8,3.4,1.9,0.2,Iris-setosa
5.0,3.0,1.6,0.2,Iris-setosa
5.0,3.4,1.6,0.4,Iris-setosa
5.2,3.5,1.5,0.2,Iris-setosa
5.2,3.4,1.4,0.2,Iris-setosa
4.7,3.2,1.6,0.2,Iris-setosa
4.8,3.1,1.6,0.2,Iris-setosa
5.4,3.4,1.5,0.4,Iris-setosa
5.2,4.1,1.5,0.1,Iris-setosa
5.5,4.2,1.4,0.2,Iris-setosa
4.9,3.1,1.5,0.1,Iris-setosa
5.0,3.2,1.2,0.2,Iris-setosa
5.5,3.5,1.3,0.2,Iris-setosa
4.9,3.1,1.5,0.1,Iris-setosa
4.4,3.0,1.3,0.2,Iris-setosa
5.1,3.4,1.5,0.2,Iris-setosa
5.0,3.5,1.3,0.3,Iris-setosa
4.5,2.3,1.3,0.3,Iris-setosa
4.4,3.2,1.3,0.2,Iris-setosa
5.0,3.5,1.6,0.6,Iris-setosa
5.1,3.8,1.9,0.4,Iris-setosa
4.8,3.0,1.4,0.3,Iris-setosa
5.1,3.8,1.6,0.2,Iris-setosa
4.6,3.2,1.4,0.2,Iris-setosa
5.3,3.7,1.5,0.2,Iris-setosa
5.0,3.3,1.4,0.2,Iris-setosa
7.0,3.2,4.7,1.4,Iris-versicolor
6.4,3.2,4.5,1.5,Iris-versicolor
6.9,3.1,4.9,1.5,Iris-versicolor
5.5,2.3,4.0,1.3,Iris-versicolor
6.5,2.8,4.6,1.5,Iris-versicolor
5.7,2.8,4.5,1.3,Iris-versicolor
6.3,3.3,4.7,1.6,Iris-versicolor
4.9,2.4,3.3,1.0,Iris-versicolor
6.6,2.9,4.6,1.3,Iris-versicolor
5.2,2.7,3.9,1.4,Iris-versicolor
5.0,2.0,3.5,1.0,Iris-versicolor
5.9,3.0,4.2,1.5,Iris-versicolor
6.0,2.2,4.0,1.0,Iris-versicolor
6.1,2.9,4.7,1.4,Iris-versicolor
5.6,2.9,3.6,1.3,Iris-versicolor
6.7,3.1,4.4,1.4,Iris-versicolor
5.6,3.0,4.5,1.5,Iris-versicolor
5.8,2.7,4.1,1.0,Iris-versicolor
6.2,2.2,4.5,1.5,Iris-versicolor
5.6,2.5,3.9,1.1,Iris-versicolor
5.9,3.2,4.8,1.8,Iris-versicolor
6.1,2.8,4.0,1.3,Iris-versicolor
6.3,2.5,4.9,1.5,Iris-versicolor
6.1,2.8,4.7,1.2,Iris-versicolor
6.4,2.9,4.3,1.3,Iris-versicolor
6.6,3.0,4.4,1.4,Iris-versicolor
6.8,2.8,4.8,1.4,Iris-versicolor
6.7,3.0,5.0,1.7,Iris-versicolor
6.0,2.9,4.5,1.5,Iris-versicolor
5.7,2.6,3.5,1.0,Iris-versicolor
5.5,2.4,3.8,1.1,Iris-versicolor
5.5,2.4,3.7,1.0,Iris-versicolor
5.8,2.7,3.9,1.2,Iris-versicolor
6.0,2.7,5.1,1.6,Iris-versicolor
5.4,3.0,4.5,1.5,Iris-versicolor
6.0,3.4,4.5,1.6,Iris-versicolor
6.7,3.1,4.7,1.5,Iris-versicolor
6.3,2.3,4.4,1.3,Iris-versicolor
5.6,3.0,4.1,1.3,Iris-versicolor
5.5,2.5,4.0,1.3,Iris-versicolor
5.5,2.6,4.4,1.2,Iris-versicolor
6.1,3.0,4.6,1.4,Iris-versicolor
5.8,2.6,4.0,1.2,Iris-versicolor
5.0,2.3,3.3,1.0,Iris-versicolor
5.6,2.7,4.2,1.3,Iris-versicolor
5.7,3.0,4.2,1.2,Iris-versicolor
5.7,2.9,4.2,1.3,Iris-versicolor
6.2,2.9,4.3,1.3,Iris-versicolor
5.1,2.5,3.0,1.1,Iris-versicolor
5.7,2.8,4.1,1.3,Iris-versicolor
6.3,3.3,6.0,2.5,Iris-virginica
5.8,2.7,5.1,1.9,Iris-virginica
7.1,3.0,5.9,2.1,Iris-virginica
6.3,2.9,5.6,1.8,Iris-virginica
6.5,3.0,5.8,2.2,Iris-virginica
7.6,3.0,6.6,2.1,Iris-virginica
4.9,2.5,4.5,1.7,Iris-virginica
7.3,2.9,6.3,1.8,Iris-virginica
6.7,2.5,5.8,1.8,Iris-virginica
7.2,3.6,6.1,2.5,Iris-virginica
6.5,3.2,5.1,2.0,Iris-virginica
6.4,2.7,5.3,1.9,Iris-virginica
6.8,3.0,5.5,2.1,Iris-virginica
5.7,2.5,5.0,2.0,Iris-virginica
5.8,2.8,5.1,2.4,Iris-virginica
6.4,3.2,5.3,2.3,Iris-virginica
6.5,3.0,5.5,1.8,Iris-virginica
7.7,3.8,6.7,2.2,Iris-virginica
7.7,2.6,6.9,2.3,Iris-virginica
6.0,2.2,5.0,1.5,Iris-virginica
6.9,3.2,5.7,2.3,Iris-virginica
5.6,2.8,4.9,2.0,Iris-virginica
7.7,2.8,6.7,2.0,Iris-virginica
6.3,2.7,4.9,1.8,Iris-virginica
6.7,3.3,5.7,2.1,Iris-virginica
7.2,3.2,6.0,1.8,Iris-virginica
6.2,2.8,4.8,1.8,Iris-virginica
6.1,3.0,4.9,1.8,Iris-virginica
6.4,2.8,5.6,2.1,Iris-virginica
7.2,3.0,5.8,1.6,Iris-virginica
7.4,2.8,6.1,1.9,Iris-virginica
7.9,3.8,6.4,2.0,Iris-virginica
6.4,2.8,5.6,2.2,Iris-virginica
6.3,2.8,5.1,1.5,Iris-virginica
6.1,2.6,5.6,1.4,Iris-virginica
7.7,3.0,6.1,2.3,Iris-virginica
6.3,3.4,5.6,2.4,Iris-virginica
6.4,3.1,5.5,1.8,Iris-virginica
6.0,3.0,4.8,1.8,Iris-virginica
6.9,3.1,5.4,2.1,Iris-virginica
6.7,3.1,5.6,2.4,Iris-virginica
6.9,3.1,5.1,2.3,Iris-virginica
5.8,2.7,5.1,1.9,Iris-virginica
6.8,3.2,5.9,2.3,Iris-virginica
6.7,3.3,5.7,2.5,Iris-virginica
6.7,3.0,5.2,2.3,Iris-virginica
6.3,2.5,5.0,1.9,Iris-virginica
6.5,3.0,5.2,2.0,Iris-virginica
6.2,3.4,5.4,2.3,Iris-virginica
5.9,3.0,5.1,1.8,Iris-virginica
@@ -0,0 +1 @@
{"class":"org.apache.spark.mllib.classification.LogisticRegressionModel","version":"1.0","numFeatures":4,"numClasses":3}
+70 -62
View File
@@ -1,31 +1,32 @@
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<artifactId>apache-spark</artifactId>
<version>1.0-SNAPSHOT</version>
<name>apache-spark</name>
<packaging>jar</packaging>
<url>http://maven.apache.org</url>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<artifactId>apache-spark</artifactId>
<version>1.0-SNAPSHOT</version>
<name>apache-spark</name>
<packaging>jar</packaging>
<url>http://maven.apache.org</url>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.11</artifactId>
<version>${org.apache.spark.spark-core.version}</version>
<scope>provided</scope>
</dependency>
<dependencies>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-sql_2.11</artifactId>
<version>${org.apache.spark.spark-sql.version}</version>
<scope>provided</scope>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.11</artifactId>
<version>${org.apache.spark.spark-core.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-sql_2.11</artifactId>
<version>${org.apache.spark.spark-sql.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
@@ -33,6 +34,12 @@
<version>${org.apache.spark.spark-streaming.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-mllib_2.11</artifactId>
<version>${org.apache.spark.spark-mllib.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming-kafka-0-10_2.11</artifactId>
@@ -48,46 +55,47 @@
<artifactId>spark-cassandra-connector-java_2.11</artifactId>
<version>${com.datastax.spark.spark-cassandra-connector-java.version}</version>
</dependency>
</dependencies>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<org.apache.spark.spark-core.version>2.3.0</org.apache.spark.spark-core.version>
<org.apache.spark.spark-sql.version>2.3.0</org.apache.spark.spark-sql.version>
<org.apache.spark.spark-streaming.version>2.3.0</org.apache.spark.spark-streaming.version>
<org.apache.spark.spark-streaming-kafka.version>2.3.0</org.apache.spark.spark-streaming-kafka.version>
<com.datastax.spark.spark-cassandra-connector.version>2.3.0</com.datastax.spark.spark-cassandra-connector.version>
<com.datastax.spark.spark-cassandra-connector-java.version>1.5.2</com.datastax.spark.spark-cassandra-connector-java.version>
<properties>
<org.apache.spark.spark-core.version>2.3.0</org.apache.spark.spark-core.version>
<org.apache.spark.spark-sql.version>2.3.0</org.apache.spark.spark-sql.version>
<org.apache.spark.spark-streaming.version>2.3.0</org.apache.spark.spark-streaming.version>
<org.apache.spark.spark-mllib.version>2.3.0</org.apache.spark.spark-mllib.version>
<org.apache.spark.spark-streaming-kafka.version>2.3.0</org.apache.spark.spark-streaming-kafka.version>
<com.datastax.spark.spark-cassandra-connector.version>2.3.0</com.datastax.spark.spark-cassandra-connector.version>
<com.datastax.spark.spark-cassandra-connector-java.version>1.5.2</com.datastax.spark.spark-cassandra-connector-java.version>
<maven-compiler-plugin.version>3.2</maven-compiler-plugin.version>
</properties>
</properties>
</project>
@@ -0,0 +1,111 @@
package com.baeldung.ml;
import java.util.HashMap;
import java.util.Map;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.mllib.classification.LogisticRegressionModel;
import org.apache.spark.mllib.classification.LogisticRegressionWithLBFGS;
import org.apache.spark.mllib.evaluation.MulticlassMetrics;
import org.apache.spark.mllib.linalg.Matrix;
import org.apache.spark.mllib.linalg.Vector;
import org.apache.spark.mllib.linalg.Vectors;
import org.apache.spark.mllib.regression.LabeledPoint;
import org.apache.spark.mllib.stat.MultivariateStatisticalSummary;
import org.apache.spark.mllib.stat.Statistics;
import scala.Tuple2;
public class MachineLearningApp {
public static void main(String[] args) {
// 1. Setting the Spark Context
SparkConf conf = new SparkConf().setAppName("Main")
.setMaster("local[2]")
.set("spark.executor.memory", "3g")
.set("spark.driver.memory", "3g");
JavaSparkContext sc = new JavaSparkContext(conf);
Logger.getLogger("org")
.setLevel(Level.OFF);
Logger.getLogger("akka")
.setLevel(Level.OFF);
// 2. Loading the Data-set
String dataFile = "data\\iris.data";
JavaRDD<String> data = sc.textFile(dataFile);
// 3. Exploratory Data Analysis
// 3.1. Creating Vector of Input Data
JavaRDD<Vector> inputData = data.map(line -> {
String[] parts = line.split(",");
double[] v = new double[parts.length - 1];
for (int i = 0; i < parts.length - 1; i++) {
v[i] = Double.parseDouble(parts[i]);
}
return Vectors.dense(v);
});
// 3.2. Performing Statistical Analysis
MultivariateStatisticalSummary summary = Statistics.colStats(inputData.rdd());
System.out.println("Summary Mean:");
System.out.println(summary.mean());
System.out.println("Summary Variance:");
System.out.println(summary.variance());
System.out.println("Summary Non-zero:");
System.out.println(summary.numNonzeros());
// 3.3. Performing Correlation Analysis
Matrix correlMatrix = Statistics.corr(inputData.rdd(), "pearson");
System.out.println("Correlation Matrix:");
System.out.println(correlMatrix.toString());
// 4. Data Preparation
// 4.1. Creating Map for Textual Output Labels
Map<String, Integer> map = new HashMap<String, Integer>();
map.put("Iris-setosa", 0);
map.put("Iris-versicolor", 1);
map.put("Iris-virginica", 2);
// 4.2. Creating LabeledPoint of Input and Output Data
JavaRDD<LabeledPoint> parsedData = data.map(line -> {
String[] parts = line.split(",");
double[] v = new double[parts.length - 1];
for (int i = 0; i < parts.length - 1; i++) {
v[i] = Double.parseDouble(parts[i]);
}
return new LabeledPoint(map.get(parts[parts.length - 1]), Vectors.dense(v));
});
// 5. Data Splitting into 80% Training and 20% Test Sets
JavaRDD<LabeledPoint>[] splits = parsedData.randomSplit(new double[] { 0.8, 0.2 }, 11L);
JavaRDD<LabeledPoint> trainingData = splits[0].cache();
JavaRDD<LabeledPoint> testData = splits[1];
// 6. Modeling
// 6.1. Model Training
LogisticRegressionModel model = new LogisticRegressionWithLBFGS().setNumClasses(3)
.run(trainingData.rdd());
// 6.2. Model Evaluation
JavaPairRDD<Object, Object> predictionAndLabels = testData.mapToPair(p -> new Tuple2<>(model.predict(p.features()), p.label()));
MulticlassMetrics metrics = new MulticlassMetrics(predictionAndLabels.rdd());
double accuracy = metrics.accuracy();
System.out.println("Model Accuracy on Test Data: " + accuracy);
// 7. Model Saving and Loading
// 7.1. Model Saving
model.save(sc.sc(), "model\\logistic-regression");
// 7.2. Model Loading
LogisticRegressionModel sameModel = LogisticRegressionModel.load(sc.sc(), "model\\logistic-regression");
// 7.3. Prediction on New Data
Vector newData = Vectors.dense(new double[] { 1, 1, 1, 1 });
double prediction = sameModel.predict(newData);
System.out.println("Model Prediction on New Data = " + prediction);
// 8. Clean-up
sc.close();
}
}
+31
View File
@@ -0,0 +1,31 @@
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
RULES_JVM_EXTERNAL_TAG = "2.0.1"
RULES_JVM_EXTERNAL_SHA = "55e8d3951647ae3dffde22b4f7f8dee11b3f70f3f89424713debd7076197eaca"
http_archive(
name = "rules_jvm_external",
strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
sha256 = RULES_JVM_EXTERNAL_SHA,
url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
)
load("@rules_jvm_external//:defs.bzl", "maven_install")
maven_install(
artifacts = [
"org.apache.commons:commons-lang3:3.9"
],
repositories = [
"https://repo1.maven.org/maven2",
]
)
http_jar (
name = "apache-commons-lang",
url = "https://repo1.maven.org/maven2/org/apache/commons/commons-lang3/3.9/commons-lang3-3.9.jar"
)
+7
View File
@@ -0,0 +1,7 @@
java_binary (
name = "BazelApp",
srcs = glob(["src/main/java/com/baeldung/*.java"]),
main_class = "com.baeldung.BazelApp",
deps = ["//bazelgreeting:greeter", "@maven//:org_apache_commons_commons_lang3"]
)
+28
View File
@@ -0,0 +1,28 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>bazel</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>bazelapp</artifactId>
<dependencies>
<dependency>
<groupId>com.baeldung</groupId>
<artifactId>bazelgreeting</artifactId>
<version>1.0.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.9</version>
</dependency>
</dependencies>
</project>
@@ -0,0 +1,15 @@
package com.baeldung;
import com.baeldung.Greetings;
import org.apache.commons.lang3.StringUtils;
public class BazelApp {
public static void main(String ... args) {
Greetings greetings = new Greetings();
System.out.println(greetings.greet("Bazel"));
System.out.println(StringUtils.lowerCase("Bazel"));
}
}
+6
View File
@@ -0,0 +1,6 @@
java_library (
name = "greeter",
srcs = glob(["src/main/java/com/baeldung/*.java"]),
visibility = ["//bazelapp:__pkg__"]
)
+15
View File
@@ -0,0 +1,15 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>bazel</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>bazelgreeting</artifactId>
</project>
@@ -0,0 +1,8 @@
package com.baeldung;
public class Greetings {
public String greet(String name) {
return "Hello ".concat(name);
}
}
+20
View File
@@ -0,0 +1,20 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>parent-modules</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>bazel</artifactId>
<packaging>pom</packaging>
<modules>
<module>bazelgreeting</module>
<module>bazelapp</module>
</modules>
</project>
@@ -0,0 +1,11 @@
package com.baeldung.concurrent.mutex;
public class SequenceGenerator {
private int currentValue = 0;
public int getNextSequence() throws InterruptedException {
currentValue = currentValue + 1;
Thread.sleep(500);
return currentValue;
}
}
@@ -0,0 +1,18 @@
package com.baeldung.concurrent.mutex;
import com.google.common.util.concurrent.Monitor;
public class SequenceGeneratorUsingMonitor extends SequenceGenerator {
private Monitor monitor = new Monitor();
@Override
public int getNextSequence() throws InterruptedException {
monitor.enter();
try {
return super.getNextSequence();
} finally {
monitor.leave();
}
}
}
@@ -0,0 +1,18 @@
package com.baeldung.concurrent.mutex;
import java.util.concurrent.locks.ReentrantLock;
public class SequenceGeneratorUsingReentrantLock extends SequenceGenerator {
private ReentrantLock mutex = new ReentrantLock();
@Override
public int getNextSequence() throws InterruptedException {
try {
mutex.lock();
return super.getNextSequence();
} finally {
mutex.unlock();
}
}
}
@@ -0,0 +1,18 @@
package com.baeldung.concurrent.mutex;
import java.util.concurrent.Semaphore;
public class SequenceGeneratorUsingSemaphore extends SequenceGenerator {
private Semaphore mutex = new Semaphore(1);
@Override
public int getNextSequence() throws InterruptedException {
try {
mutex.acquire();
return super.getNextSequence();
} finally {
mutex.release();
}
}
}
@@ -0,0 +1,12 @@
package com.baeldung.concurrent.mutex;
public class SequenceGeneratorUsingSynchronizedBlock extends SequenceGenerator {
@Override
public int getNextSequence() throws InterruptedException {
synchronized (this) {
return super.getNextSequence();
}
}
}
@@ -0,0 +1,10 @@
package com.baeldung.concurrent.mutex;
public class SequenceGeneratorUsingSynchronizedMethod extends SequenceGenerator {
@Override
public synchronized int getNextSequence() throws InterruptedException {
return super.getNextSequence();
}
}
@@ -0,0 +1,81 @@
package com.baeldung.concurrent.mutex;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.junit.Assert;
import org.junit.Test;
import com.baeldung.concurrent.mutex.SequenceGenerator;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingMonitor;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingReentrantLock;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSemaphore;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSynchronizedBlock;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSynchronizedMethod;
public class MutexUnitTest {
private final int RANGE = 30;
@Test
public void givenUnsafeSequenceGenerator_whenRaceCondition_thenUnexpectedBehavior() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGenerator());
Assert.assertNotEquals(RANGE, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSynchronizedMethod_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSynchronizedMethod());
Assert.assertEquals(RANGE, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSynchronizedBlock_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSynchronizedBlock());
Assert.assertEquals(RANGE, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingReentrantLock_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingReentrantLock());
Assert.assertEquals(RANGE, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSemaphore_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSemaphore());
Assert.assertEquals(RANGE, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingMonitor_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingMonitor());
Assert.assertEquals(RANGE, uniqueSequences.size());
}
private Set<Integer> getASetOFUniqueSequences(SequenceGenerator generator) throws Exception {
ExecutorService executor = Executors.newFixedThreadPool(3);
Set<Integer> uniqueSequences = new HashSet<>();
List<Future<Integer>> futures = new ArrayList<>();
for (int i = 0; i < RANGE; i++) {
futures.add(executor.submit(generator::getNextSequence));
}
for (Future<Integer> future : futures) {
uniqueSequences.add(future.get());
}
executor.awaitTermination(15, TimeUnit.SECONDS);
executor.shutdown();
return uniqueSequences;
}
}

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