BAEL-6717 Convert One Enum to Another Enum in Java (#14400)

- added new module core-java-lang-6
- added data model and test for enums

core-java-modules/core-java-lang-6/README.md

@@ -0,0 +1,7 @@
+## Core Java Lang (Part 6)
+
+This module contains articles about core features in the Java language
+
+### Relevant Articles:
+
+- [Convert One Enum to Another Enum in Java](<link - TODO>)

core-java-modules/core-java-lang-6/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         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>
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>core-java-lang-6</artifactId>
+
+    <dependencies>
+        <!-- https://mvnrepository.com/artifact/org.mapstruct/mapstruct -->
+        <dependency>
+            <groupId>org.mapstruct</groupId>
+            <artifactId>mapstruct</artifactId>
+            <version>${mapstruct.version}</version>
+        </dependency>
+
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.5.1</version>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                    <annotationProcessorPaths>
+                        <!-- https://mvnrepository.com/artifact/org.mapstruct/mapstruct-processor -->
+                        <path>
+                            <groupId>org.mapstruct</groupId>
+                            <artifactId>mapstruct-processor</artifactId>
+                            <version>${mapstruct.version}</version>
+                        </path>
+                    </annotationProcessorPaths>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <mapstruct.version>1.5.5.Final</mapstruct.version>
+    </properties>
+
+</project>

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/EnumMapper.java

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+package com.baeldung.enums.mapping;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.MappingConstants;
+import org.mapstruct.ValueMapping;
+
+import com.baeldung.enums.mapping.order.CmsOrderStatus;
+import com.baeldung.enums.mapping.order.OrderStatus;
+import com.baeldung.enums.mapping.user.ExternalUserStatus;
+import com.baeldung.enums.mapping.user.UserStatus;
+
+@Mapper
+public interface EnumMapper {
+
+    CmsOrderStatus map(OrderStatus orderStatus);
+
+    @ValueMapping(source = "PENDING", target = "INACTIVE")
+    @ValueMapping(source = "BLOCKED", target = "INACTIVE")
+    @ValueMapping(source = "INACTIVATED_BY_SYSTEM", target = "INACTIVE")
+    @ValueMapping(source = "DELETED", target = "INACTIVE")
+    ExternalUserStatus map(UserStatus userStatus);
+
+    @ValueMapping(source = MappingConstants.ANY_REMAINING, target = "INACTIVE")
+    ExternalUserStatus mapDefault(UserStatus userStatus);
+
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/order/CmsOrderStatus.java

@@ -0,0 +1,5 @@
+package com.baeldung.enums.mapping.order;
+
+public enum CmsOrderStatus {
+    PENDING, APPROVED, PACKED, DELIVERED
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/order/OrderStatus.java

@@ -0,0 +1,13 @@
+package com.baeldung.enums.mapping.order;
+
+public enum OrderStatus {
+    PENDING, APPROVED, PACKED, DELIVERED;
+
+    public CmsOrderStatus toCmsOrderStatus() {
+        return CmsOrderStatus.valueOf(this.name());
+    }
+
+    public CmsOrderStatus toCmsOrderStatusOrdinal() {
+        return CmsOrderStatus.values()[this.ordinal()];
+    }
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/user/ExternalUserStatus.java

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+package com.baeldung.enums.mapping.user;
+
+public enum ExternalUserStatus {
+    ACTIVE, INACTIVE
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/user/UserStatus.java

@@ -0,0 +1,26 @@
+package com.baeldung.enums.mapping.user;
+
+public enum UserStatus {
+    PENDING, ACTIVE, BLOCKED, INACTIVATED_BY_SYSTEM, DELETED;
+
+    public ExternalUserStatus toExternalUserStatusViaSwitchStatement() {
+        return switch (this) {
+            case PENDING, BLOCKED, INACTIVATED_BY_SYSTEM, DELETED -> ExternalUserStatus.INACTIVE;
+            case ACTIVE -> ExternalUserStatus.ACTIVE;
+        };
+    }
+
+    public ExternalUserStatus toExternalUserStatusViaRegularSwitch() {
+        switch (this) {
+        case PENDING:
+        case BLOCKED:
+        case INACTIVATED_BY_SYSTEM:
+        case DELETED:
+            return ExternalUserStatus.INACTIVE;
+        case ACTIVE:
+            return ExternalUserStatus.ACTIVE;
+        }
+        return null;
+    }
+
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/user/UserStatusMapper.java

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+package com.baeldung.enums.mapping.user;
+
+import java.util.EnumMap;
+
+public class UserStatusMapper {
+    public static EnumMap<UserStatus, ExternalUserStatus> statusesMap;
+
+    static {
+        statusesMap = new EnumMap<>(UserStatus.class);
+        statusesMap.put(UserStatus.PENDING, ExternalUserStatus.INACTIVE);
+        statusesMap.put(UserStatus.BLOCKED, ExternalUserStatus.INACTIVE);
+        statusesMap.put(UserStatus.DELETED, ExternalUserStatus.INACTIVE);
+        statusesMap.put(UserStatus.INACTIVATED_BY_SYSTEM, ExternalUserStatus.INACTIVE);
+        statusesMap.put(UserStatus.ACTIVE, ExternalUserStatus.ACTIVE);
+    }
+
+    public static ExternalUserStatus toExternalUserStatus(UserStatus userStatus) {
+        return statusesMap.get(userStatus);
+    }
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/enums/mapping/user/UserStatusWithFieldVariable.java

@@ -0,0 +1,19 @@
+package com.baeldung.enums.mapping.user;
+
+public enum UserStatusWithFieldVariable {
+    PENDING(ExternalUserStatus.INACTIVE),
+    ACTIVE(ExternalUserStatus.ACTIVE),
+    BLOCKED(ExternalUserStatus.INACTIVE),
+    INACTIVATED_BY_SYSTEM(ExternalUserStatus.INACTIVE),
+    DELETED(ExternalUserStatus.INACTIVE);
+
+    private final ExternalUserStatus externalUserStatus;
+
+    UserStatusWithFieldVariable(ExternalUserStatus externalUserStatus) {
+        this.externalUserStatus = externalUserStatus;
+    }
+
+    public ExternalUserStatus toExternalUserStatus() {
+        return externalUserStatus;
+    }
+}

core-java-modules/core-java-lang-6/src/test/java/com/baeldung/enums/mapping/EnumConversionUnitTest.java

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+package com.baeldung.enums.mapping;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.enums.mapping.order.CmsOrderStatus;
+import com.baeldung.enums.mapping.order.OrderStatus;
+import com.baeldung.enums.mapping.user.ExternalUserStatus;
+import com.baeldung.enums.mapping.user.UserStatus;
+import com.baeldung.enums.mapping.user.UserStatusMapper;
+import com.baeldung.enums.mapping.user.UserStatusWithFieldVariable;
+
+public class EnumConversionUnitTest {
+
+    @Test
+    void whenUsingSwitchStatement_thenEnumConverted() {
+        UserStatus userStatusDeleted = UserStatus.DELETED;
+        UserStatus userStatusPending = UserStatus.PENDING;
+        UserStatus userStatusActive = UserStatus.ACTIVE;
+
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusDeleted.toExternalUserStatusViaSwitchStatement());
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusPending.toExternalUserStatusViaSwitchStatement());
+        assertEquals(ExternalUserStatus.ACTIVE, userStatusActive.toExternalUserStatusViaSwitchStatement());
+    }
+
+    @Test
+    void whenUsingSwitch_thenEnumConverted() {
+        UserStatus userStatusDeleted = UserStatus.DELETED;
+        UserStatus userStatusPending = UserStatus.PENDING;
+        UserStatus userStatusActive = UserStatus.ACTIVE;
+
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusDeleted.toExternalUserStatusViaRegularSwitch());
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusPending.toExternalUserStatusViaRegularSwitch());
+        assertEquals(ExternalUserStatus.ACTIVE, userStatusActive.toExternalUserStatusViaRegularSwitch());
+    }
+
+    @Test
+    void whenUsingFieldVariable_thenEnumConverted() {
+        UserStatusWithFieldVariable userStatusDeleted = UserStatusWithFieldVariable.DELETED;
+        UserStatusWithFieldVariable userStatusPending = UserStatusWithFieldVariable.PENDING;
+        UserStatusWithFieldVariable userStatusActive = UserStatusWithFieldVariable.ACTIVE;
+
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusDeleted.toExternalUserStatus());
+        assertEquals(ExternalUserStatus.INACTIVE, userStatusPending.toExternalUserStatus());
+        assertEquals(ExternalUserStatus.ACTIVE, userStatusActive.toExternalUserStatus());
+    }
+
+    @Test
+    void whenUsingEnumMap_thenEnumConverted() {
+        UserStatus userStatusDeleted = UserStatus.DELETED;
+        UserStatus userStatusPending = UserStatus.PENDING;
+        UserStatus userStatusActive = UserStatus.ACTIVE;
+
+        assertEquals(ExternalUserStatus.INACTIVE, UserStatusMapper.toExternalUserStatus(userStatusDeleted));
+        assertEquals(ExternalUserStatus.INACTIVE, UserStatusMapper.toExternalUserStatus(userStatusPending));
+        assertEquals(ExternalUserStatus.ACTIVE, UserStatusMapper.toExternalUserStatus(userStatusActive));
+    }
+
+    @Test
+    void whenUsingOrdinalApproach_thenEnumConverted() {
+        OrderStatus orderStatusApproved = OrderStatus.APPROVED;
+        OrderStatus orderStatusDelivered = OrderStatus.DELIVERED;
+        OrderStatus orderStatusPending = OrderStatus.PENDING;
+
+        assertEquals(CmsOrderStatus.APPROVED, orderStatusApproved.toCmsOrderStatusOrdinal());
+        assertEquals(CmsOrderStatus.DELIVERED, orderStatusDelivered.toCmsOrderStatusOrdinal());
+        assertEquals(CmsOrderStatus.PENDING, orderStatusPending.toCmsOrderStatusOrdinal());
+    }
+
+    @Test
+    void whenUsingEnumName_thenEnumConverted() {
+        OrderStatus orderStatusApproved = OrderStatus.APPROVED;
+        OrderStatus orderStatusDelivered = OrderStatus.DELIVERED;
+        OrderStatus orderStatusPending = OrderStatus.PENDING;
+
+        assertEquals(CmsOrderStatus.APPROVED, orderStatusApproved.toCmsOrderStatus());
+        assertEquals(CmsOrderStatus.DELIVERED, orderStatusDelivered.toCmsOrderStatus());
+        assertEquals(CmsOrderStatus.PENDING, orderStatusPending.toCmsOrderStatus());
+    }
+
+    @Test
+    void whenUsingDefaultMapstruct_thenEnumConverted() {
+        UserStatus userStatusDeleted = UserStatus.DELETED;
+        UserStatus userStatusPending = UserStatus.PENDING;
+        UserStatus userStatusActive = UserStatus.ACTIVE;
+
+        EnumMapper enumMapper = new EnumMapperImpl();
+
+        assertEquals(ExternalUserStatus.INACTIVE, enumMapper.map(userStatusDeleted));
+        assertEquals(ExternalUserStatus.INACTIVE, enumMapper.map(userStatusPending));
+        assertEquals(ExternalUserStatus.ACTIVE, enumMapper.map(userStatusActive));
+    }
+
+    @Test
+    void whenUsingConfiguredMapstruct_thenEnumConverted() {
+        OrderStatus orderStatusApproved = OrderStatus.APPROVED;
+        OrderStatus orderStatusDelivered = OrderStatus.DELIVERED;
+        OrderStatus orderStatusPending = OrderStatus.PENDING;
+
+        EnumMapper enumMapper = new EnumMapperImpl();
+
+        assertEquals(CmsOrderStatus.APPROVED, enumMapper.map(orderStatusApproved));
+        assertEquals(CmsOrderStatus.DELIVERED, enumMapper.map(orderStatusDelivered));
+        assertEquals(CmsOrderStatus.PENDING, enumMapper.map(orderStatusPending));
+    }
+
+    @Test
+    void whenUsingConfiguredWithRemainingMapstruct_thenEnumConverted() {
+        UserStatus userStatusDeleted = UserStatus.DELETED;
+        UserStatus userStatusPending = UserStatus.PENDING;
+        UserStatus userStatusActive = UserStatus.ACTIVE;
+
+        EnumMapper enumMapper = new EnumMapperImpl();
+
+        assertEquals(ExternalUserStatus.INACTIVE, enumMapper.mapDefault(userStatusDeleted));
+        assertEquals(ExternalUserStatus.INACTIVE, enumMapper.mapDefault(userStatusPending));
+        assertEquals(ExternalUserStatus.ACTIVE, enumMapper.mapDefault(userStatusActive));
+    }
+}

core-java-modules/pom.xml

@@ -93,6 +93,7 @@
         <module>core-java-lang-3</module>
         <module>core-java-lang-4</module>
         <module>core-java-lang-5</module>
+        <module>core-java-lang-6</module>
         <module>core-java-lang-math</module>
         <module>core-java-lang-math-2</module>
         <module>core-java-lang-oop-constructors</module>