BAEL-5979 Instanceof Alternatives (#13082)

* simple-thymeleaf-expression

* expression-update

* instanceof

* instanceof

* instanceof

* update

* Update pom.xml

* Update pom.xml

* instanceof

* update

* instanceofnew

* instanceofnew

* instanceofnew

* instanceofnew

* instanceofnew

* instanceofnew

* update

* pom

* Revert "pom"

This reverts commit c5075e6ba7e1e91159864d57bcbc18dd90314e16.

* Revert "Update pom.xml"

This reverts commit 7dd02df1aea201572fb64d8bc4a2990a94b6b4c0.

* Revert "Revert "Update pom.xml""

This reverts commit a02a1f67d16eb0bc781cc588af48f36fcc93d601.

* Update pom.xml

* Revert "Update pom.xml"

This reverts commit 7dd02df1aea201572fb64d8bc4a2990a94b6b4c0.

* Update pom.xml

* JAVA-8436: Remove AssertJ depenendency from the child modules - part 4

* Update pom.xml

* JAVA-8436: Remove AssertJ depenendency from the child modules - part 4

* BAEL-5979 Instanceof Alternatives

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/enumallt/DinosaurEnum.java

@@ -0,0 +1,19 @@
+package com.baeldung.instanceofalternative.enumallt;
+
+public enum DinosaurEnum {
+    Anatotitan {
+        @Override
+        public String move() {
+            return "running";
+        }
+    },
+    Euraptor {
+        @Override
+        public String move() {
+            return "flying";
+        }
+    };
+
+    public abstract String move();
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Anatotitan.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Anatotitan extends Dinosaur {
+    // polymorphism
+    @Override
+    public String move() {
+        return "running";
+    }
+
+    // non-polymorphism
+    public String run() {
+        return "running";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Dinosaur.java

@@ -0,0 +1,9 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Dinosaur {
+
+    public String move() {
+        return "default movement";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Euraptor.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Euraptor extends Dinosaur {
+    // polymorphism
+    @Override
+    public String move() {
+        return "flying";
+    }
+
+    // non-polymorphism
+    public String flies() {
+        return "flying";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Anatotitan.java

@@ -0,0 +1,14 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class Anatotitan implements Dino {
+
+    String run() {
+        return "running";
+    }
+
+    @Override
+    public String move(Visitor dinobehave) {
+        return dinobehave.visit(this);
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Dino.java

@@ -0,0 +1,7 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public interface Dino {
+
+    String move(Visitor dinoMove);
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/DinoVisitorImpl.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class DinoVisitorImpl implements Visitor {
+
+    @Override
+    public String visit(Anatotitan anatotitan) {
+        return anatotitan.run();
+    }
+
+    @Override
+    public String visit(Euraptor euraptor) {
+        return euraptor.flies();
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Euraptor.java

@@ -0,0 +1,14 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class Euraptor implements Dino {
+
+    String flies() {
+        return "flying";
+    }
+
+    @Override
+    public String move(Visitor dinobehave) {
+        return dinobehave.visit(this);
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Visitor.java

@@ -0,0 +1,9 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public interface Visitor {
+
+    String visit(Anatotitan anatotitan);
+
+    String visit(Euraptor euraptor);
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/EnumUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.enumallt.*;
+
+public class EnumUnitTest {
+    @Test
+    public void givenADinosaurSpecie_whenUsingEnum_thenGetMovementOfEuraptor() {
+
+        assertEquals("flying", moveDinosaurUsingEnum(DinosaurEnum.Euraptor));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingEnum_thenGetMovementOfAnatotitan() {
+        assertEquals("running", moveDinosaurUsingEnum(DinosaurEnum.Anatotitan));
+    }
+
+    public static String moveDinosaurUsingEnum(DinosaurEnum dinosaurenum) {
+        return dinosaurenum.move();
+
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/ExampleSetupUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class ExampleSetupUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingInstancof_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingInstanceof(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingInstanceof_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingInstanceof(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingInstanceof(Dinosaur dinosaur) {
+
+        if (dinosaur instanceof Anatotitan) {
+
+            Anatotitan anatotitan = (Anatotitan) dinosaur;
+            return anatotitan.run();
+        } else if (dinosaur instanceof Euraptor) {
+            Euraptor euraptor = (Euraptor) dinosaur;
+            return euraptor.flies();
+        }
+        return "";
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/GetClassUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class GetClassUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingGetClass_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingGetClass(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingGetClass_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingGetClass(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingGetClass(Dinosaur dinosaur) {
+
+        if (dinosaur.getClass()
+            .equals(Anatotitan.class)) {
+
+            Anatotitan anatotitan = (Anatotitan) dinosaur;
+            return anatotitan.run();
+        } else if (dinosaur.getClass()
+            .equals(Euraptor.class)) {
+            Euraptor euraptor = (Euraptor) dinosaur;
+            return euraptor.flies();
+        }
+        return "";
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/PolymorphismUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class PolymorphismUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingPolymorphism_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingPolymorphism(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingPolymorphism_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingPolymorphism(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingPolymorphism(Dinosaur dinosaur) {
+        return dinosaur.move();
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/VisitorsPatternUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.visitorspattern.*;
+
+public class VisitorsPatternUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingVisitorPattern_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingVisitorPattern((Dino) new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingVisitorPattern_thenGetMovementOfEuraptor() {
+
+        assertEquals("flying", moveDinosaurUsingVisitorPattern((Dino) new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingVisitorPattern(Dino dinosaur) {
+        Visitor visitor = new DinoVisitorImpl();
+
+        return dinosaur.move(visitor);
+    }
+
+}