BAEL-9402: Calculate the Difference of Two Angle Measures in Java

algorithms-modules/algorithms-twoanglesdifference/pom.xml

@@ -0,0 +1,71 @@
+<?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>
+    <artifactId>algorithms-twoanglesdifference</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-twoanglesdifference</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>algorithms-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <!-- Compile target; run-time JDK can be 25 -->
+        <maven.compiler.release>21</maven.compiler.release>
+
+        <junit.jupiter.version>5.11.0</junit.jupiter.version>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <surefire.version>3.2.5</surefire.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <!-- Ensure JUnit 5 is on the test classpath (parent usually manages the version) -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+    <!-- Usually already configured by the parents; harmless to keep -->
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-pmd-plugin</artifactId>
+                <version>3.26.0</version>
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <release>${maven.compiler.release}</release>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${surefire.version}</version>
+                <configuration>
+                    <useModulePath>false</useModulePath>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

algorithms-modules/algorithms-twoanglesdifference/src/main/java/com/baeldung/algorithms/twoanglesdifference/AngleDifferenceCalculator.java

@@ -0,0 +1,64 @@
+/**
+ * Package to host code for calculating three types of angle difference
+ */
+package com.baeldung.algorithms.twoanglesdifference;
+
+public class AngleDifferenceCalculator {
+
+    /**
+     * Normalizes an angle to be within the range [0, 360).
+     *
+     * @param angle The angle in degrees.
+     * @return The normalized angle.
+     */
+    public static double normalizeAngle(double angle) {
+        return (angle % 360 + 360) % 360;
+    }
+
+    /**
+     * Calculates the absolute difference between two angles.
+     *
+     * @param angle1 The first angle in degrees.
+     * @param angle2 The second angle in degrees.
+     * @return The absolute difference in degrees.
+     */
+    public static double absoluteDifference(double angle1, double angle2) {
+        return Math.abs(angle1 - angle2);
+    }
+
+    /**
+     * Calculates the shortest difference between two angles.
+     *
+     * @param angle1 The first angle in degrees.
+     * @param angle2 The second angle in degrees.
+     * @return The shortest difference in degrees (0 to 180).
+     */
+    public static double shortestDifference(double angle1, double angle2) {
+        double diff = absoluteDifference(normalizeAngle(angle1), normalizeAngle(angle2));
+        return Math.min(diff, 360 - diff);
+    }
+
+    /**
+     * Calculates the signed shortest difference between two angles.
+     * A positive result indicates counter-clockwise rotation, a negative result indicates clockwise.
+     *
+     * @param angle1 The first angle in degrees.
+     * @param angle2 The second angle in degrees.
+     * @return The signed shortest difference in degrees (-180 to 180).
+     */
+    public static double signedShortestDifference(double angle1, double angle2) {
+        double normalizedAngle1 = normalizeAngle(angle1);
+        double normalizedAngle2 = normalizeAngle(angle2);
+        double diff = normalizedAngle2 - normalizedAngle1;
+
+        if (diff > 180) {
+            return diff - 360;
+        } else if (diff < -180) {
+            return diff + 360;
+        } else {
+            return diff;
+        }
+    }
+}
+
+

algorithms-modules/algorithms-twoanglesdifference/src/test/java/com/baeldung/algorithms/twoanglesdifference/AngleDifferenceCalculatorTest.java

@@ -0,0 +1,47 @@
+/**
+ * Package to host JUnit Test code for AngleDifferenceCalculator Class
+ */
+package com.baeldung.algorithms.twoanglesdifference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+
+
+class AngleDifferenceCalculatorTest {
+
+    private static final double EPSILON = 0.0001;
+
+    @Test
+    void whenNormalizingAngle_thenReturnsCorrectRange() {
+        assertEquals(90, AngleDifferenceCalculator.normalizeAngle(450), EPSILON);
+        assertEquals(30, AngleDifferenceCalculator.normalizeAngle(390), EPSILON);
+        assertEquals(330, AngleDifferenceCalculator.normalizeAngle(-30), EPSILON);
+        assertEquals(0, AngleDifferenceCalculator.normalizeAngle(360), EPSILON);
+    }
+
+    @Test
+    void whenCalculatingAbsoluteDifference_thenReturnsCorrectValue() {
+        assertEquals(100, AngleDifferenceCalculator.absoluteDifference(10, 110), EPSILON);
+        assertEquals(290, AngleDifferenceCalculator.absoluteDifference(10, 300), EPSILON);
+        assertEquals(30, AngleDifferenceCalculator.absoluteDifference(-30, 0), EPSILON);
+    }
+
+    @Test
+    void whenCalculatingShortestDifference_thenReturnsCorrectValue() {
+        assertEquals(100, AngleDifferenceCalculator.shortestDifference(10, 110), EPSILON);
+        assertEquals(70, AngleDifferenceCalculator.shortestDifference(10, 300), EPSILON);
+        assertEquals(30, AngleDifferenceCalculator.shortestDifference(-30, 0), EPSILON);
+        assertEquals(0, AngleDifferenceCalculator.shortestDifference(360, 0), EPSILON);
+    }
+
+    @Test
+    void whenCalculatingSignedShortestDifference_thenReturnsCorrectValue() {
+        assertEquals(100, AngleDifferenceCalculator.signedShortestDifference(10, 110), EPSILON);
+        assertEquals(-70, AngleDifferenceCalculator.signedShortestDifference(10, 300), EPSILON);
+        assertEquals(30, AngleDifferenceCalculator.signedShortestDifference(-30, 0), EPSILON);
+        assertEquals(70, AngleDifferenceCalculator.signedShortestDifference(300, 10), EPSILON);
+    }
+}
+

algorithms-modules/pom.xml

@@ -30,6 +30,7 @@
         <module>algorithms-sorting</module>
         <module>algorithms-sorting-2</module>
         <module>algorithms-sorting-3</module>
+        <module>algorithms-twoanglesdifference</module>
     </modules>
 
     <properties>

pom.xml

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="UTF-8"?>
+ <?xml version="1.0" encoding="UTF-8"?>
 <!--suppress PyInterpreter -->
 <project xmlns="http://maven.apache.org/POM/4.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xml-modules/jaxb/src/main/java/com/baeldung/jaxb/gen/ObjectFactory.java

@@ -1,6 +1,9 @@
 
 package com.baeldung.jaxb.gen;
 
+import javax.xml.namespace.QName;
+import jakarta.xml.bind.JAXBElement;
+import jakarta.xml.bind.annotation.XmlElementDecl;
 import jakarta.xml.bind.annotation.XmlRegistry;
 
 
@@ -21,6 +24,8 @@
 @XmlRegistry
 public class ObjectFactory {
 
+    private final static QName _UserRequest_QNAME = new QName("http://www.baeldung.com/jaxb/gen", "userRequest");
+    private final static QName _UserResponse_QNAME = new QName("http://www.baeldung.com/jaxb/gen", "userResponse");
 
     /**
      * Create a new ObjectFactory that can be used to create new instances of schema derived classes for package: com.baeldung.jaxb.gen
@@ -45,4 +50,30 @@ public UserResponse createUserResponse() {
         return new UserResponse();
     }
 
+    /**
+     * Create an instance of {@link JAXBElement }{@code <}{@link UserRequest }{@code >}
+     * 
+     * @param value
+     *     Java instance representing xml element's value.
+     * @return
+     *     the new instance of {@link JAXBElement }{@code <}{@link UserRequest }{@code >}
+     */
+    @XmlElementDecl(namespace = "http://www.baeldung.com/jaxb/gen", name = "userRequest")
+    public JAXBElement<UserRequest> createUserRequest(UserRequest value) {
+        return new JAXBElement<UserRequest>(_UserRequest_QNAME, UserRequest.class, null, value);
+    }
+
+    /**
+     * Create an instance of {@link JAXBElement }{@code <}{@link UserResponse }{@code >}
+     * 
+     * @param value
+     *     Java instance representing xml element's value.
+     * @return
+     *     the new instance of {@link JAXBElement }{@code <}{@link UserResponse }{@code >}
+     */
+    @XmlElementDecl(namespace = "http://www.baeldung.com/jaxb/gen", name = "userResponse")
+    public JAXBElement<UserResponse> createUserResponse(UserResponse value) {
+        return new JAXBElement<UserResponse>(_UserResponse_QNAME, UserResponse.class, null, value);
+    }
+
 }

xml-modules/jaxb/src/main/java/com/baeldung/jaxb/gen/UserRequest.java

@@ -1,11 +1,9 @@
 
 package com.baeldung.jaxb.gen;
 
-import java.io.Serializable;
 import jakarta.xml.bind.annotation.XmlAccessType;
 import jakarta.xml.bind.annotation.XmlAccessorType;
 import jakarta.xml.bind.annotation.XmlElement;
-import jakarta.xml.bind.annotation.XmlRootElement;
 import jakarta.xml.bind.annotation.XmlType;
 
 
@@ -34,12 +32,8 @@
     "id",
     "name"
 })
-@XmlRootElement(name = "userRequest")
-public class UserRequest
-    implements Serializable
-{
+public class UserRequest {
 
-    private final static long serialVersionUID = -1L;
     protected int id;
     @XmlElement(required = true)
     protected String name;

xml-modules/jaxb/src/main/java/com/baeldung/jaxb/gen/UserResponse.java

@@ -1,16 +1,12 @@
 
 package com.baeldung.jaxb.gen;
 
-import java.io.Serializable;
-import java.util.Calendar;
+import javax.xml.datatype.XMLGregorianCalendar;
 import jakarta.xml.bind.annotation.XmlAccessType;
 import jakarta.xml.bind.annotation.XmlAccessorType;
 import jakarta.xml.bind.annotation.XmlElement;
-import jakarta.xml.bind.annotation.XmlRootElement;
 import jakarta.xml.bind.annotation.XmlSchemaType;
 import jakarta.xml.bind.annotation.XmlType;
-import jakarta.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
-import org.w3._2001.xmlschema.Adapter1;
 
 
 /**
@@ -42,21 +38,16 @@
     "gender",
     "created"
 })
-@XmlRootElement(name = "userResponse")
-public class UserResponse
-    implements Serializable
-{
+public class UserResponse {
 
-    private final static long serialVersionUID = -1L;
     protected int id;
     @XmlElement(required = true)
     protected String name;
     @XmlElement(required = true)
     protected String gender;
-    @XmlElement(required = true, type = String.class)
-    @XmlJavaTypeAdapter(Adapter1 .class)
+    @XmlElement(required = true)
     @XmlSchemaType(name = "dateTime")
-    protected Calendar created;
+    protected XMLGregorianCalendar created;
 
     /**
      * Gets the value of the id property.
@@ -127,10 +118,10 @@ public void setGender(String value) {
      * 
      * @return
      *     possible object is
-     *     {@link String }
+     *     {@link XMLGregorianCalendar }
      *     
      */
-    public Calendar getCreated() {
+    public XMLGregorianCalendar getCreated() {
         return created;
     }
 
@@ -139,10 +130,10 @@ public Calendar getCreated() {
      * 
      * @param value
      *     allowed object is
-     *     {@link String }
+     *     {@link XMLGregorianCalendar }
      *     
      */
-    public void setCreated(Calendar value) {
+    public void setCreated(XMLGregorianCalendar value) {
         this.created = value;
     }