Feature/bael 5133 utility class constructor (#11421)

* BAEL-5133: initial commit

* BAEL-5133: better example

* BAEL-5133: add Lombok examples

* BAEL-5133: add interface and enum examples

* BAEL-5133: add exception

* BAEL-5133: add suppress warning

* BAEL-5133: dummy

Co-authored-by: ashleyfrieze <ashley@incredible.org.uk>

core-java-modules/core-java-lang-oop-methods/pom.xml

@@ -2,6 +2,7 @@
 <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>
     <artifactId>core-java-lang-oop-methods</artifactId>
     <name>core-java-lang-oop-methods</name>
@@ -33,7 +34,9 @@
     </dependencies>
 
     <properties>
-        <lombok.version>1.18.12</lombok.version>
+        <lombok.version>1.18.22</lombok.version>
+        <commons-lang.version>2.6</commons-lang.version>
+        <assertj-core.version>3.10.0</assertj-core.version>
         <equalsverifier.version>3.0.3</equalsverifier.version>
     </properties>
 

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/StringUtils.java

@@ -0,0 +1,17 @@
+package com.baeldung.utilities;
+
+public final class StringUtils {
+
+    private StringUtils() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+
+    public static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    public static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/alternatives/StringUtilsEnum.java

@@ -0,0 +1,13 @@
+package com.baeldung.utilities.alternatives;
+
+public enum StringUtilsEnum {;
+
+    public static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    public static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/alternatives/StringUtilsInterface.java

@@ -0,0 +1,13 @@
+package com.baeldung.utilities.alternatives;
+
+public interface StringUtilsInterface {
+
+    static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/lombok/StringUtilsWithNoArgsConstructor.java

@@ -0,0 +1,17 @@
+package com.baeldung.utilities.lombok;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access= AccessLevel.PRIVATE)
+public final class StringUtilsWithNoArgsConstructor {
+
+    public static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    public static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/lombok/StringUtilsWithUtilityClass.java

@@ -0,0 +1,16 @@
+package com.baeldung.utilities.lombok;
+
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class StringUtilsWithUtilityClass {
+
+    public static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    public static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/utilities/warning/StringUtilsSuppressWarning.java

@@ -0,0 +1,14 @@
+package com.baeldung.utilities.warning;
+
+@SuppressWarnings("java:S1118")
+public final class StringUtilsSuppressWarning {
+
+    public static boolean isEmpty(String source) {
+        return source == null || source.length() == 0;
+    }
+
+    public static String wrap(String source, String wrapWith) {
+        return isEmpty(source) ? source : wrapWith + source + wrapWith;
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/StringUtilsUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.utilities;
+
+import org.junit.jupiter.api.Test;
+import static org.assertj.core.api.Assertions.*;
+
+class StringUtilsUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtils.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtils.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtils.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtils.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/alternatives/StringUtilsEnumUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.utilities.alternatives;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsEnumUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtilsEnum.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtilsEnum.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtilsEnum.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtilsEnum.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/alternatives/StringUtilsInterfaceUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.utilities.alternatives;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsInterfaceUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtilsInterface.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtilsInterface.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtilsInterface.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtilsInterface.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/lombok/StringUtilsWithNoArgsConstructorUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.utilities.lombok;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsWithNoArgsConstructorUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtilsWithNoArgsConstructor.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtilsWithNoArgsConstructor.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtilsWithNoArgsConstructor.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtilsWithNoArgsConstructor.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/lombok/StringUtilsWithUtilityClassUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.utilities.lombok;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsWithUtilityClassUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtilsWithUtilityClass.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtilsWithUtilityClass.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtilsWithUtilityClass.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtilsWithUtilityClass.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}

core-java-modules/core-java-lang-oop-methods/src/test/java/com/baeldung/utilities/warning/StringUtilsStringUtilsSuppressWarningUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.utilities.warning;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsStringUtilsSuppressWarningUnitTest {
+
+    @Test
+    void givenAnEmptyString_whenCallingIsEmpty_thenResultIsTrue() {
+        assertThat(StringUtilsSuppressWarning.isEmpty("")).isTrue();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingIsEmpty_thenResultIsFalse() {
+        assertThat(StringUtilsSuppressWarning.isEmpty("asd")).isFalse();
+    }
+
+    @Test
+    void givenAnEmptyString_whenCallingWrap_thenResultIsAnEmptyString() {
+        assertThat(StringUtilsSuppressWarning.wrap("", "wrapper")).isEmpty();
+    }
+
+    @Test
+    void givenNonEmptyString_whenCallingWrap_thenResultIsWrappedString() {
+        assertThat(StringUtilsSuppressWarning.wrap("asd", "wrapper")).isEqualTo("wrapperasdwrapper");
+    }
+
+}