Category Entity and VO

3-Domain/src/main/java/Category/Category.java

@@ -0,0 +1,25 @@
+package Category;
+
+/**
+ * A Category that can be assigned to a link to group links with similar content.
+ * Categories need a unique name, by which they can be identified for the user.
+ * They can be created by the user.
+ */
+public class Category {
+
+	private CategoryName name;
+	private CategoryId id;
+
+	public Category(CategoryName name, CategoryId id) {
+		this.name = name;
+		this.id = id;
+	}
+
+	public CategoryName getName() {
+		return name;
+	}
+
+	public CategoryId getId() {
+		return id;
+	}
+}

3-Domain/src/main/java/Category/CategoryId.java

@@ -0,0 +1,4 @@
+package Category;
+
+public record CategoryId(int id) {
+}

3-Domain/src/main/java/Category/CategoryName.java

@@ -0,0 +1,43 @@
+package Category;
+
+import Exeptions.IllegalValueObjectArgument;
+
+import java.util.Objects;
+
+public class CategoryName {
+	private final String name;
+
+	public String getName() {
+		return name;
+	}
+
+	public CategoryName(final String name) throws IllegalValueObjectArgument {
+		validateName(name);
+		this.name = name;
+	}
+
+	private void validateName(final String name) throws IllegalValueObjectArgument {
+		if (name == null) {
+			throw new IllegalValueObjectArgument("A Category name can not be null.");
+		}
+
+		if (name.isBlank() || name.isEmpty() || name.length() < 3) {
+			throw new IllegalValueObjectArgument("A Category name must be a valid string of at least 3 characters.");
+		}
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) return true;
+		if (o == null || getClass() != o.getClass()) return false;
+
+		CategoryName that = (CategoryName) o;
+
+		return Objects.equals(name, that.name);
+	}
+
+	@Override
+	public int hashCode() {
+		return name != null ? name.hashCode() : 0;
+	}
+}

3-Domain/src/main/java/Exeptions/IllegalValueObjectArgument.java

@@ -0,0 +1,8 @@
+package Exeptions;
+
+public class IllegalValueObjectArgument extends Exception {
+
+	public IllegalValueObjectArgument(String message) {
+		super(message);
+	}
+}

3-Domain/src/test/java/Category/CategoryIdTest.java

@@ -0,0 +1,26 @@
+package Category;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class CategoryIdTest {
+
+	@Test
+	void constructorWorks() {
+		int id = 432;
+		CategoryId sut = new CategoryId(id);
+
+		assertEquals(id, sut.id());
+	}
+
+	@Test
+	void equalsWorks() {
+		int id = 432;
+		CategoryId first = new CategoryId(id);
+		CategoryId second = new CategoryId(id);
+
+		assertEquals(first, second);
+	}
+
+}

3-Domain/src/test/java/Category/CategoryNameTest.java

@@ -0,0 +1,47 @@
+package Category;
+
+import Exeptions.IllegalValueObjectArgument;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class CategoryNameTest {
+
+	@Test
+	void getNameWorks() throws IllegalValueObjectArgument {
+		String name = "libaries";
+		CategoryName sut = new CategoryName(name);
+
+		assertEquals(name, sut.getName());
+	}
+
+	@Test
+	void constructorThrowsNull() {
+		String nullString = null;
+		assertThrows(IllegalValueObjectArgument.class, () -> new CategoryName(nullString));
+	}
+
+	@Test
+	void constructorThrowsBlank() {
+		String blankString = "    ";
+		assertThrows(IllegalValueObjectArgument.class, () -> new CategoryName(blankString));
+	}
+
+	@Test
+	void constructorThrowsEmpty() {
+		String emptyString = "";
+		assertThrows(IllegalValueObjectArgument.class, () -> new CategoryName(emptyString));
+	}
+
+	@Test
+	void constructorThrowsTooShort() {
+		String shortString = "da";
+		assertThrows(IllegalValueObjectArgument.class, () -> new CategoryName(shortString));
+	}
+
+	@Test
+	void testEquals() {
+	}
+
+}

3-Domain/src/test/java/Category/CategoryTest.java

@@ -0,0 +1,29 @@
+package Category;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+
+class CategoryTest {
+
+	@Test
+	void getNameWorks() {
+		CategoryId id = new CategoryId(32);
+		CategoryName name = mock(CategoryName.class);
+
+		Category sut = new Category(name, id);
+
+		assertEquals(name, sut.getName());
+	}
+
+	@Test
+	void getIdWorks() {
+		CategoryId id = new CategoryId(32);
+		CategoryName name = mock(CategoryName.class);
+
+		Category sut = new Category(name, id);
+
+		assertEquals(id, sut.getId());
+	}
+}