java-12

mkyong · mkyong · commit 56e5b57e482d · 2020-05-18T17:31:36.000+08:00
diff --git a/java-12/pom.xml b/java-12/pom.xml
@@ -0,0 +1,37 @@
+<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.mkyong</groupId>
+    <artifactId>java12</artifactId>
+    <version>1.0</version>
+
+    <name>java-12</name>
+    <url>https://www.mkyong.com</url>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>12</maven.compiler.source>
+        <maven.compiler.target>12</maven.compiler.target>
+        <java.version>12</java.version>
+    </properties>
+
+    <dependencies>
+    </dependencies>
+
+    <build>
+        <finalName>java12</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.0</version>
+                <configuration>
+                    <source>${java.version}</source>
+                    <target>${java.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/java-12/src/main/java/com/mkyong/java12/HelloApp.java b/java-12/src/main/java/com/mkyong/java12/HelloApp.java
@@ -0,0 +1,9 @@
+package com.mkyong.java12;
+
+public class HelloApp {
+
+    public static void main(String[] args) {
+        System.out.println("Hello Java 12");
+    }
+
+}
diff --git a/java-12/src/main/java/com/mkyong/java12/jep325/SwitchExample.java b/java-12/src/main/java/com/mkyong/java12/jep325/SwitchExample.java
@@ -0,0 +1,90 @@
+package com.mkyong.java12.jep325;
+
+/*
+    javac --enable-preview --release 12 Example.java
+    java --enable-preview Example
+ */
+public class SwitchExample {
+
+    public static void main(String[] args) {
+
+        System.out.println(getNumber(1));
+        System.out.println(getNumber(3));
+        System.out.println(getNumber(6));
+        System.out.println(getNumber(10));
+
+    }
+
+    // Traditional switch statement
+    private static String getNumber(int number) {
+        String result = "";
+        switch (number) {
+            case 1:
+            case 2:
+                result = "one or two";
+                break;
+            case 3:
+                result = "three";
+                break;
+            case 4:
+            case 5:
+            case 6:
+                result = "four or five or six";
+                break;
+            default:
+                result = "unknown";
+        }
+        ;
+        return result;
+    }
+
+    // Multiple case labels
+    private static String getNumberMultipleCase(int number) {
+        String result = "";
+        switch (number) {
+            case 1, 2:
+                result = "one or two";
+                break;
+            case 3:
+                result = "three";
+                break;
+            case 4, 5, 6:
+                result = "four or five or six";
+                break;
+            default:
+                result = "unknown";
+        }
+        ;
+        return result;
+    }
+
+    // break with value is dropped in favor of `yield` in Java 13.
+    /*private static String getNumberViaBreak(int number) {
+        String result = switch (number) {
+            case 1:
+            case 2:
+                break "one or two";
+            case 3:
+                break "three";
+            case 4:
+            case 5:
+            case 6:
+                break "four or five or six";
+            default:
+                break "unknown";
+        };
+        return result;
+    }*/
+
+    // arrow, label rules, case L
+    private static String getNumberViaArrow(int number) {
+        String result = switch (number) {
+            case 1, 2 -> "one or two";
+            case 3 -> "three";
+            case 4, 5, 6 -> "four or five or six";
+            default -> "unknown";
+        };
+        return result;
+    }
+
+}
