Introduce SessionIdGenerationStrategy

Closes gh-11

spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastIndexedSessionRepository.java

@@ -48,6 +48,8 @@ import org.springframework.session.MapSession;
 import org.springframework.session.PrincipalNameIndexResolver;
 import org.springframework.session.SaveMode;
 import org.springframework.session.Session;
+import org.springframework.session.SessionIdGenerationStrategy;
+import org.springframework.session.UuidSessionIdGenerationStrategy;
 import org.springframework.session.events.AbstractSessionEvent;
 import org.springframework.session.events.SessionCreatedEvent;
 import org.springframework.session.events.SessionDeletedEvent;
@@ -151,6 +153,8 @@ public class HazelcastIndexedSessionRepository
 
 	private UUID sessionListenerId;
 
+	private SessionIdGenerationStrategy sessionIdGenerationStrategy = UuidSessionIdGenerationStrategy.getInstance();
+
 	/**
 	 * Create a new {@link HazelcastIndexedSessionRepository} instance.
 	 * @param hazelcastInstance the {@link HazelcastInstance} to use for managing sessions
@@ -245,7 +249,7 @@ public class HazelcastIndexedSessionRepository
 
 	@Override
 	public HazelcastSession createSession() {
-		MapSession cached = new MapSession();
+		MapSession cached = new MapSession(this.sessionIdGenerationStrategy);
 		cached.setMaxInactiveInterval(this.defaultMaxInactiveInterval);
 		HazelcastSession session = new HazelcastSession(cached, true);
 		session.flushImmediateIfNecessary();
@@ -349,6 +353,16 @@ public class HazelcastIndexedSessionRepository
 		this.eventPublisher.publishEvent(new SessionExpiredEvent(this, event.getOldValue()));
 	}
 
+	/**
+	 * Set the {@link SessionIdGenerationStrategy} to use to generate session ids.
+	 * @param sessionIdGenerationStrategy the {@link SessionIdGenerationStrategy} to use
+	 * @since 3.2
+	 */
+	public void setSessionIdGenerationStrategy(SessionIdGenerationStrategy sessionIdGenerationStrategy) {
+		Assert.notNull(sessionIdGenerationStrategy, "sessionIdGenerationStrategy cannot be null");
+		this.sessionIdGenerationStrategy = sessionIdGenerationStrategy;
+	}
+
 	/**
 	 * A custom implementation of {@link Session} that uses a {@link MapSession} as the
 	 * basis for its mapping. It keeps track if changes have been made since last save.
@@ -405,7 +419,8 @@ public class HazelcastIndexedSessionRepository
 
 		@Override
 		public String changeSessionId() {
-			String newSessionId = this.delegate.changeSessionId();
+			String newSessionId = HazelcastIndexedSessionRepository.this.sessionIdGenerationStrategy.generate();
+			this.delegate.setId(newSessionId);
 			this.sessionIdChanged = true;
 			return newSessionId;
 		}

spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/config/annotation/web/http/HazelcastHttpSessionConfiguration.java

@@ -38,6 +38,8 @@ import org.springframework.session.IndexResolver;
 import org.springframework.session.MapSession;
 import org.springframework.session.SaveMode;
 import org.springframework.session.Session;
+import org.springframework.session.SessionIdGenerationStrategy;
+import org.springframework.session.UuidSessionIdGenerationStrategy;
 import org.springframework.session.config.SessionRepositoryCustomizer;
 import org.springframework.session.config.annotation.web.http.SpringHttpSessionConfiguration;
 import org.springframework.session.hazelcast.HazelcastIndexedSessionRepository;
@@ -75,6 +77,8 @@ public class HazelcastHttpSessionConfiguration implements ImportAware {
 
 	private List<SessionRepositoryCustomizer<HazelcastIndexedSessionRepository>> sessionRepositoryCustomizers;
 
+	private SessionIdGenerationStrategy sessionIdGenerationStrategy = UuidSessionIdGenerationStrategy.getInstance();
+
 	@Bean
 	public FindByIndexNameSessionRepository<?> sessionRepository() {
 		return createHazelcastIndexedSessionRepository();
@@ -158,9 +162,15 @@ public class HazelcastHttpSessionConfiguration implements ImportAware {
 		sessionRepository.setDefaultMaxInactiveInterval(this.maxInactiveInterval);
 		sessionRepository.setFlushMode(this.flushMode);
 		sessionRepository.setSaveMode(this.saveMode);
+		sessionRepository.setSessionIdGenerationStrategy(this.sessionIdGenerationStrategy);
 		this.sessionRepositoryCustomizers
 				.forEach((sessionRepositoryCustomizer) -> sessionRepositoryCustomizer.customize(sessionRepository));
 		return sessionRepository;
 	}
 
+	@Autowired(required = false)
+	public void setSessionIdGenerationStrategy(SessionIdGenerationStrategy sessionIdGenerationStrategy) {
+		this.sessionIdGenerationStrategy = sessionIdGenerationStrategy;
+	}
+
 }

spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastIndexedSessionRepositoryTests.java

@@ -465,4 +465,31 @@ class HazelcastIndexedSessionRepositoryTests {
 		verifyNoMoreInteractions(this.sessions);
 	}
 
+	@Test
+	void createSessionWhenSessionIdGenerationStrategyThenUses() {
+		this.repository.setSessionIdGenerationStrategy(() -> "test");
+		HazelcastSession session = this.repository.createSession();
+		assertThat(session.getId()).isEqualTo("test");
+		assertThat(session.changeSessionId()).isEqualTo("test");
+	}
+
+	@Test
+	void setSessionIdGenerationStrategyWhenNullThenThrowsException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.repository.setSessionIdGenerationStrategy(null))
+				.withMessage("sessionIdGenerationStrategy cannot be null");
+	}
+
+	@Test
+	void findByIdWhenChangeSessionIdThenUsesSessionIdGenerationStrategy() {
+		this.repository.setSessionIdGenerationStrategy(() -> "test");
+		MapSession saved = new MapSession("original");
+		saved.setAttribute("savedName", "savedValue");
+		given(this.sessions.get(eq(saved.getId()))).willReturn(saved);
+
+		HazelcastSession session = this.repository.findById(saved.getId());
+
+		assertThat(session.getId()).isEqualTo(saved.getId());
+		assertThat(session.changeSessionId()).isEqualTo("test");
+	}
+
 }

spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/config/annotation/web/http/HazelcastHttpSessionConfigurationTests.java

@@ -36,6 +36,8 @@ import org.springframework.session.FlushMode;
 import org.springframework.session.IndexResolver;
 import org.springframework.session.SaveMode;
 import org.springframework.session.Session;
+import org.springframework.session.SessionIdGenerationStrategy;
+import org.springframework.session.UuidSessionIdGenerationStrategy;
 import org.springframework.session.config.SessionRepositoryCustomizer;
 import org.springframework.session.hazelcast.HazelcastIndexedSessionRepository;
 import org.springframework.session.hazelcast.config.annotation.SpringSessionHazelcastInstance;
@@ -238,6 +240,24 @@ class HazelcastHttpSessionConfigurationTests {
 		assertThat(sessionRepository).extracting("defaultMaxInactiveInterval").isEqualTo(Duration.ZERO);
 	}
 
+	@Test
+	void registerWhenSessionIdGenerationStrategyBeanThenUses() {
+		registerAndRefresh(DefaultConfiguration.class, SessionIdGenerationStrategyConfiguration.class);
+		HazelcastIndexedSessionRepository sessionRepository = this.context
+				.getBean(HazelcastIndexedSessionRepository.class);
+		assertThat(sessionRepository).extracting("sessionIdGenerationStrategy")
+				.isInstanceOf(TestSessionIdGenerationStrategy.class);
+	}
+
+	@Test
+	void registerWhenNoSessionIdGenerationStrategyBeanThenDefault() {
+		registerAndRefresh(DefaultConfiguration.class);
+		HazelcastIndexedSessionRepository sessionRepository = this.context
+				.getBean(HazelcastIndexedSessionRepository.class);
+		assertThat(sessionRepository).extracting("sessionIdGenerationStrategy")
+				.isInstanceOf(UuidSessionIdGenerationStrategy.class);
+	}
+
 	private void registerAndRefresh(Class<?>... annotatedClasses) {
 		this.context.register(annotatedClasses);
 		this.context.refresh();
@@ -465,4 +485,23 @@ class HazelcastHttpSessionConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class SessionIdGenerationStrategyConfiguration {
+
+		@Bean
+		SessionIdGenerationStrategy sessionIdGenerationStrategy() {
+			return new TestSessionIdGenerationStrategy();
+		}
+
+	}
+
+	static class TestSessionIdGenerationStrategy implements SessionIdGenerationStrategy {
+
+		@Override
+		public String generate() {
+			return "test";
+		}
+
+	}
+
 }