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23: Scala Traits, Mixins, self-type annotation & DI with Cake pattern

Q01. What is a trait in Scala? A01. In Scala, trait is a collection of abstract and non-abstract methods. You can create trait that can have all abstract methods or some abstract and some non-abstract methods. A variable that is declared either by using val or var keyword in a...

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3 Reasons Why I started Learning Scala

Why learn Scala? and where to use Scala? are very popular questions in forums like LinkedIn, Quora, Stack Overflow, etc. Here is my take on learning Scala with 3 reasons.

#1. I am already proficient in Java

Learning new programming languages (e.g. Scala) and paradigms (e.g.

…

FAQs Data: 02: Getting started with Spark Scala on IntelliJ IDEA with Maven

Intellij IDEA IDE - Spark, Scala & Maven

This extends FAQs Data: 01: Getting started with Spark Scala on IntelliJ IDEA to package the Spark & run it via command-line. The dependent libraries configured via Maven pom.xml. Make sure Maven is installed on your machine & set in the path.

Step 1: Extend the previous pom.xml file from

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>spark-on-scala</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

</project>

<?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">

<groupId>org.example</groupId>

<artifactId>spark-on-scala</artifactId>

<version>1.0-SNAPSHOT</version>

<maven.compiler.source>8</maven.compiler.source>

<maven.compiler.target>8</maven.compiler.target>

</properties>

</project>

TO:

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.example</groupId>
    <artifactId>spark-on-scala2</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>${project.artifactId}</name>
    <description>My wonderfull scala app</description>
    <inceptionYear>2018</inceptionYear>
    <licenses>
        <license>
            <name>My License</name>
            <url>http://....</url>
            <distribution>repo</distribution>
        </license>
    </licenses>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <encoding>UTF-8</encoding>
        <scala.version>2.12.15</scala.version>
        <scala.compat.version>2.12</scala.compat.version>
        <spec2.version>4.2.0</spec2.version>
        <spark.version>3.2.1</spark.version>

    </properties>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_${scala.compat.version}</artifactId>
            <version>${spark.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- Test -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.scalatest</groupId>
            <artifactId>scalatest_${scala.compat.version}</artifactId>
            <version>3.1.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.specs2</groupId>
            <artifactId>specs2-core_${scala.compat.version}</artifactId>
            <version>${spec2.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.specs2</groupId>
            <artifactId>specs2-junit_${scala.compat.version}</artifactId>
            <version>${spec2.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <sourceDirectory>src/main/scala</sourceDirectory>
        <testSourceDirectory>src/test/scala</testSourceDirectory>
        <plugins>
            <plugin>
                <!-- see http://davidb.github.com/scala-maven-plugin -->
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.3.2</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                        <configuration>
                            <args>
                                <arg>-dependencyfile</arg>
                                <arg>${project.build.directory}/.scala_dependencies</arg>
                            </args>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.21.0</version>
                <configuration>
                    <!-- Tests will be run with scalatest-maven-plugin instead -->
                    <skipTests>true</skipTests>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.scalatest</groupId>
                <artifactId>scalatest-maven-plugin</artifactId>
                <version>2.0.0</version>
                <configuration>
                    <reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
                    <junitxml>.</junitxml>
                    <filereports>WDF TestSuite.txt</filereports>
                </configuration>
                <executions>
                    <execution>
                        <id>test</id>
                        <goals>
                            <goal>test</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

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<groupId>org.example</groupId>

<artifactId>spark-on-scala2</artifactId>

<version>1.0-SNAPSHOT</version>

<name>${project.artifactId}</name>

<description>My wonderfull scala app</description>

<name>My License</name>

</license>

</licenses>

<maven.compiler.source>1.8</maven.compiler.source>

<maven.compiler.target>1.8</maven.compiler.target>

<scala.version>2.12.15</scala.version>

<scala.compat.version>2.12</scala.compat.version>

<spec2.version>4.2.0</spec2.version>

<spark.version>3.2.1</spark.version>

</properties>

<groupId>org.scala-lang</groupId>

<artifactId>scala-library</artifactId>

<version>${scala.version}</version>

</dependency>

<groupId>org.apache.spark</groupId>

<artifactId>spark-sql_${scala.compat.version}</artifactId>

<version>${spark.version}</version>

<scope>provided</scope>

</dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

</dependency>

<groupId>org.scalatest</groupId>

<artifactId>scalatest_${scala.compat.version}</artifactId>

</dependency>

<groupId>org.specs2</groupId>

<artifactId>specs2-core_${scala.compat.version}</artifactId>

<version>${spec2.version}</version>

</dependency>

<groupId>org.specs2</groupId>

<artifactId>specs2-junit_${scala.compat.version}</artifactId>

<version>${spec2.version}</version>

</dependency>

</dependencies>

<build>

<sourceDirectory>src/main/scala</sourceDirectory>

<testSourceDirectory>src/test/scala</testSourceDirectory>

<groupId>net.alchim31.maven</groupId>

<artifactId>scala-maven-plugin</artifactId>

<goals>

<goal>compile</goal>

<goal>testCompile</goal>

</goals>

<args>

<arg>-dependencyfile</arg>

<arg>${project.build.directory}/.scala_dependencies</arg>

</args>

</configuration>

</execution>

</executions>

</plugin>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-surefire-plugin</artifactId>

</configuration>

</plugin>

<groupId>org.scalatest</groupId>

<artifactId>scalatest-maven-plugin</artifactId>

<reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>

<filereports>WDF TestSuite.txt</filereports>

</configuration>

<goals>

</goals>

</execution>

</executions>

</plugin>

</plugins>

</build>

</project>

Step 2: Rename “src/test/java”

…

Blog Archives

23: Scala Traits, Mixins, self-type annotation & DI with Cake pattern

3 Reasons Why I started Learning Scala

FAQs Data: 01: Getting started with Spark Scala on IntelliJ IDEA

FAQs Data: 02: Getting started with Spark Scala on IntelliJ IDEA with Maven

FAQs Data: 03: ScalaTest using IntelliJ IDEA IDE

FAQs Data: 04: ScalaTest of Spark using IntelliJ IDEA IDE

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