Code samples for Java Switch Statement

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Nick 2019-12-08 10:28:27 +00:00
parent 6cd385e4c0
commit b5e5132133
2 changed files with 134 additions and 0 deletions

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<?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>com.baeldung</groupId>
<artifactId>core-java-13</artifactId>
<version>0.1.0-SNAPSHOT</version>
<name>core-java-13</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>
<relativePath>../../</relativePath>
</parent>
<dependencies>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>${maven.compiler.source.version}</source>
<target>${maven.compiler.target.version}</target>
<release>13</release>
<compilerArgs>--enable-preview</compilerArgs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M3</version>
<configuration>
<argLine>--enable-preview</argLine>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<maven.compiler.source.version>13</maven.compiler.source.version>
<maven.compiler.target.version>13</maven.compiler.target.version>
<assertj.version>3.6.1</assertj.version>
</properties>
</project>

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package com.baeldung.switchExpression;
import static java.time.Month.AUGUST;
import static java.time.Month.JUNE;
import static org.junit.Assert.assertEquals;
import java.time.Month;
import java.util.function.Function;
import org.junit.Test;
public class SwitchExpressionsUnitTest {
@Test
@SuppressWarnings ("preview")
public void switchExpression() {
var month = JUNE;
var result = switch (month) {
case JANUARY, JUNE, JULY -> 3;
case FEBRUARY, SEPTEMBER, OCTOBER, NOVEMBER, DECEMBER -> 1;
case MARCH, MAY, APRIL -> 2;
default -> 0;
};
assertEquals(result, 3);
}
@Test
@SuppressWarnings ("preview")
public void switchExpressionWithYieldKeyword() {
var month = AUGUST;
var result = switch (month) {
case JANUARY, JUNE, JULY -> 3;
case FEBRUARY, SEPTEMBER, OCTOBER, NOVEMBER, DECEMBER -> 1;
case MARCH, MAY, APRIL, AUGUST -> {
int monthLength = month.toString().length();
yield monthLength * 4;
}
default -> 0;
};
assertEquals(24, result);
}
@Test
@SuppressWarnings ("preview")
public void switchStatementWithReturnInsideBlock() {
Function<Month, Integer> func = (month) -> {
switch (month) {
case JANUARY, JUNE, JULY -> { return 3; }
default -> { return 0; }
}
};
assertEquals(Integer.valueOf(3), func.apply(Month.JANUARY));
}
@Test
@SuppressWarnings ("preview")
public void switchExpressionWithAllCasesCovered() {
var month = AUGUST;
var result = switch (month) {
case JANUARY, JUNE, JULY -> 3;
case FEBRUARY, SEPTEMBER, OCTOBER, NOVEMBER, DECEMBER -> 1;
case MARCH, MAY, APRIL, AUGUST -> 2;
};
assertEquals(result, 2);
}
}