feat(domain): add SlugValidator with comprehensive validation rules

server/skillhub-domain/pom.xml

@@ -15,5 +15,10 @@
             <groupId>jakarta.persistence</groupId>
             <artifactId>jakarta.persistence-api</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

server/skillhub-domain/src/main/java/com/iflytek/skillhub/domain/namespace/SlugValidator.java

@@ -0,0 +1,36 @@
+package com.iflytek.skillhub.domain.namespace;
+
+import java.util.Set;
+import java.util.regex.Pattern;
+
+public class SlugValidator {
+
+    private static final int MIN_LENGTH = 2;
+    private static final int MAX_LENGTH = 64;
+    private static final Pattern SLUG_PATTERN = Pattern.compile("^[a-z0-9]([a-z0-9-]*[a-z0-9])?$");
+    private static final Set<String> RESERVED_SLUGS = Set.of(
+            "admin", "api", "dashboard", "search", "auth",
+            "me", "global", "system", "static", "assets", "health"
+    );
+
+    public static void validate(String slug) {
+        if (slug == null || slug.isBlank()) {
+            throw new IllegalArgumentException("Slug cannot be null or blank");
+        }
+        if (slug.length() < MIN_LENGTH || slug.length() > MAX_LENGTH) {
+            throw new IllegalArgumentException(
+                    String.format("Slug length must be between %d and %d characters", MIN_LENGTH, MAX_LENGTH));
+        }
+        if (!SLUG_PATTERN.matcher(slug).matches()) {
+            throw new IllegalArgumentException(
+                    "Slug must contain only lowercase alphanumeric characters and hyphens, " +
+                    "and must start and end with an alphanumeric character");
+        }
+        if (slug.contains("--")) {
+            throw new IllegalArgumentException("Slug cannot contain consecutive hyphens");
+        }
+        if (RESERVED_SLUGS.contains(slug)) {
+            throw new IllegalArgumentException("Slug '" + slug + "' is reserved and cannot be used");
+        }
+    }
+}

server/skillhub-domain/src/test/java/com/iflytek/skillhub/domain/namespace/SlugValidatorTest.java

@@ -0,0 +1,57 @@
+package com.iflytek.skillhub.domain.namespace;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class SlugValidatorTest {
+    @Test
+    void shouldAcceptValidSlug() {
+        assertDoesNotThrow(() -> SlugValidator.validate("my-namespace"));
+        assertDoesNotThrow(() -> SlugValidator.validate("ab"));
+        assertDoesNotThrow(() -> SlugValidator.validate("test123"));
+        assertDoesNotThrow(() -> SlugValidator.validate("my-team-2024"));
+    }
+    @Test
+    void shouldRejectTooShort() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("a"));
+        assertTrue(ex.getMessage().contains("length"));
+    }
+    @Test
+    void shouldRejectTooLong() {
+        String longSlug = "a".repeat(65);
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate(longSlug));
+        assertTrue(ex.getMessage().contains("length"));
+    }
+    @Test
+    void shouldRejectUpperCase() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("MyNamespace"));
+        assertTrue(ex.getMessage().contains("lowercase"));
+    }
+    @Test
+    void shouldRejectStartingWithHyphen() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("-namespace"));
+        assertTrue(ex.getMessage().contains("alphanumeric"));
+    }
+    @Test
+    void shouldRejectEndingWithHyphen() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("namespace-"));
+        assertTrue(ex.getMessage().contains("alphanumeric"));
+    }
+    @Test
+    void shouldRejectDoubleHyphen() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("my--namespace"));
+        assertTrue(ex.getMessage().contains("consecutive"));
+    }
+    @Test
+    void shouldRejectReservedWords() {
+        assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("admin"));
+        assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("api"));
+        assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("global"));
+        assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("system"));
+    }
+    @Test
+    void shouldRejectSpecialCharacters() {
+        Exception ex = assertThrows(IllegalArgumentException.class, () -> SlugValidator.validate("my_namespace"));
+        assertTrue(ex.getMessage().contains("lowercase") || ex.getMessage().contains("alphanumeric"));
+    }
+}