Specialized Utilities

public abstract class BaseDistributedCacheManager<K, V> implements DistributedCacheManager<K, V> {
    
    // Abstract methods for implementation
    protected abstract void putInternal(K key, V value, Duration expiration);
    protected abstract Optional<V> getInternal(K key);
    protected abstract boolean removeInternal(K key);
    protected abstract void clearInternal();
    
    // Template methods with common functionality
    @Override
    public void put(K key, V value);
    
    @Override
    public void put(K key, V value, Duration expiration);
    
    @Override
    public Optional<V> get(K key);
    
    @Override
    public boolean containsKey(K key);
    
    @Override
    public boolean remove(K key);
    
    @Override
    public void clear();
    
    @Override
    public Set<K> keys();
    
    @Override
    public long size();
    
    // Batch operations
    public Map<K, V> getAll(Collection<K> keys);
    public void putAll(Map<K, V> entries, Duration expiration);
    public void removeAll(Collection<K> keys);
    
    // Statistics and monitoring
    public CacheStatistics getStatistics();
    public void resetStatistics();
}

public interface MappableDistributedCacheManager<K, V> extends DistributedCacheManager<K, V> {
    
    // Key transformation operations
    <T> MappableDistributedCacheManager<T, V> mapKeys(Function<K, T> keyMapper);
    <T> MappableDistributedCacheManager<K, T> mapValues(Function<V, T> valueMapper);
    
    // Filtered views
    MappableDistributedCacheManager<K, V> filterKeys(Predicate<K> keyPredicate);
    MappableDistributedCacheManager<K, V> filterValues(Predicate<V> valuePredicate);
    
    // Conditional operations
    boolean putIfAbsent(K key, V value);
    boolean putIfAbsent(K key, V value, Duration expiration);
    boolean replace(K key, V oldValue, V newValue);
    V computeIfAbsent(K key, Function<K, V> mappingFunction);
    V computeIfPresent(K key, BiFunction<K, V, V> remappingFunction);
}

public class DistributedCacheObject<T> implements Serializable {
    
    // Core properties
    private final T value;
    private final Instant createdAt;
    private final Instant expiresAt;
    private final Map<String, String> metadata;
    
    // Constructors
    public DistributedCacheObject(T value);
    public DistributedCacheObject(T value, Duration ttl);
    public DistributedCacheObject(T value, Instant expiresAt, Map<String, String> metadata);
    
    // Getters
    public T getValue();
    public Instant getCreatedAt();
    public Instant getExpiresAt();
    public Map<String, String> getMetadata();
    
    // Utility methods
    public boolean isExpired();
    public boolean isExpired(Instant currentTime);
    public Duration getTimeToLive();
    public Duration getAge();
    
    // Factory methods
    public static <T> DistributedCacheObject<T> of(T value);
    public static <T> DistributedCacheObject<T> of(T value, Duration ttl);
}

@Component
public class RedisDistributedCacheManager<K, V> extends BaseDistributedCacheManager<K, V> {
    
    private final RedisTemplate<String, Object> redisTemplate;
    private final ObjectMapper objectMapper;
    private final String keyPrefix;
    
    public RedisDistributedCacheManager(RedisTemplate<String, Object> redisTemplate,
                                      ObjectMapper objectMapper) {
        this.redisTemplate = redisTemplate;
        this.objectMapper = objectMapper;
        this.keyPrefix = "cas:cache:";
    }
    
    @Override
    protected void putInternal(K key, V value, Duration expiration) {
        try {
            String redisKey = keyPrefix + key.toString();
            DistributedCacheObject<V> cacheObject = new DistributedCacheObject<>(value, expiration);
            
            String serialized = objectMapper.writeValueAsString(cacheObject);
            redisTemplate.opsForValue().set(redisKey, serialized, expiration);
            
        } catch (Exception e) {
            log.error("Failed to put value in Redis cache", e);
            throw new CacheException("Cache put operation failed", e);
        }
    }
    
    @Override
    protected Optional<V> getInternal(K key) {
        try {
            String redisKey = keyPrefix + key.toString();
            String serialized = (String) redisTemplate.opsForValue().get(redisKey);
            
            if (serialized != null) {
                DistributedCacheObject<V> cacheObject = objectMapper.readValue(
                    serialized, 
                    new TypeReference<DistributedCacheObject<V>>() {}
                );
                
                if (!cacheObject.isExpired()) {
                    return Optional.of(cacheObject.getValue());
                } else {
                    // Remove expired entry
                    redisTemplate.delete(redisKey);
                }
            }
            
            return Optional.empty();
            
        } catch (Exception e) {
            log.error("Failed to get value from Redis cache", e);
            return Optional.empty();
        }
    }
    
    @Override
    protected boolean removeInternal(K key) {
        String redisKey = keyPrefix + key.toString();
        return Boolean.TRUE.equals(redisTemplate.delete(redisKey));
    }
    
    @Override
    protected void clearInternal() {
        Set<String> keys = redisTemplate.keys(keyPrefix + "*");
        if (keys != null && !keys.isEmpty()) {
            redisTemplate.delete(keys);
        }
    }
}

@Service
public class UserCacheService {
    
    private final MappableDistributedCacheManager<String, User> userCache;
    
    public void cacheUser(User user) {
        // Cache by user ID
        userCache.put(user.getId(), user, Duration.ofHours(1));
        
        // Create mapped view for email-based lookups
        MappableDistributedCacheManager<String, User> emailCache = userCache
            .mapKeys(User::getEmail)
            .filterValues(u -> u.getEmail() != null);
        
        emailCache.putIfAbsent(user.getEmail(), user, Duration.ofHours(1));
    }
    
    public Optional<User> getUserById(String userId) {
        return userCache.get(userId);
    }
    
    public Optional<User> getActiveUser(String userId) {
        // Filtered view for active users only
        return userCache
            .filterValues(User::isActive)
            .get(userId);
    }
}

public interface WatcherService {
    
    // Service lifecycle
    void start(String name);
    void start(String name, Runnable onChange);
    void stop();
    boolean isRunning();
    
    // Watch operations
    void watch(Path file, Runnable onChange);
    void watch(Resource resource, Runnable onChange);
    void watch(File file, Consumer<WatchEvent<?>> eventConsumer);
    
    // Configuration
    void setWatchDelay(long delay, TimeUnit timeUnit);
    void setWatchEvents(WatchEvent.Kind<?>... eventTypes);
}

public class FileWatcherService implements WatcherService {
    
    // Configuration
    private long watchDelayMs = 1000;
    private WatchEvent.Kind<?>[] watchEvents = {
        StandardWatchEventKinds.ENTRY_CREATE,
        StandardWatchEventKinds.ENTRY_MODIFY,
        StandardWatchEventKinds.ENTRY_DELETE
    };
    
    // Constructors
    public FileWatcherService();
    public FileWatcherService(ExecutorService executorService);
    
    // WatcherService implementation
    @Override
    public void start(String name);
    
    @Override
    public void watch(Path file, Runnable onChange);
    
    @Override
    public void watch(Resource resource, Runnable onChange);
    
    // Configuration methods
    public void setWatchDelay(long delay, TimeUnit timeUnit);
    public void setWatchEvents(WatchEvent.Kind<?>... eventTypes);
    
    // Advanced watch operations
    public void watchDirectory(Path directory, 
                             Predicate<Path> fileFilter, 
                             Consumer<WatchEvent<?>> eventConsumer);
    
    public void watchRecursively(Path rootDirectory, 
                               Consumer<WatchEvent<?>> eventConsumer);
}

public class PathWatcherService implements WatcherService {
    
    // Enhanced filtering
    private final Set<PathMatcher> includePatterns;
    private final Set<PathMatcher> excludePatterns;
    
    // Constructors
    public PathWatcherService();
    public PathWatcherService(FileSystem fileSystem);
    
    // Pattern-based filtering
    public void addIncludePattern(String pattern);
    public void addExcludePattern(String pattern);
    public void setIncludePatterns(Collection<String> patterns);
    public void setExcludePatterns(Collection<String> patterns);
    
    // Advanced watch operations
    public void watchWithFilter(Path path, 
                              PathMatcher filter, 
                              Consumer<WatchEvent<?>> eventConsumer);
}

@Component
public class ConfigurationWatcher {
    
    private final FileWatcherService fileWatcher;
    private final ConfigurationService configService;
    
    @PostConstruct
    public void initializeWatching() {
        // Watch main configuration file
        Path configFile = Paths.get("application.properties");
        fileWatcher.watch(configFile, this::reloadConfiguration);
        
        // Watch configuration directory
        Path configDir = Paths.get("config");
        fileWatcher.watchDirectory(
            configDir,
            path -> path.toString().endsWith(".properties"),
            this::handleConfigurationChange
        );
        
        // Start watching
        fileWatcher.start("configuration-watcher");
    }
    
    private void reloadConfiguration() {
        try {
            log.info("Configuration file changed, reloading...");
            configService.reload();
            log.info("Configuration reloaded successfully");
        } catch (Exception e) {
            log.error("Failed to reload configuration", e);
        }
    }
    
    private void handleConfigurationChange(WatchEvent<?> event) {
        WatchEvent.Kind<?> kind = event.kind();
        Path path = (Path) event.context();
        
        log.info("Configuration change detected: {} - {}", kind.name(), path);
        
        if (kind == StandardWatchEventKinds.ENTRY_MODIFY || 
            kind == StandardWatchEventKinds.ENTRY_CREATE) {
            reloadConfiguration();
        }
    }
}

@Component
public class ServiceRegistryWatcher {
    
    private final PathWatcherService pathWatcher;
    private final ServiceRegistry serviceRegistry;
    
    @PostConstruct
    public void startWatching() {
        // Configure patterns for service files
        pathWatcher.addIncludePattern("*.json");
        pathWatcher.addIncludePattern("*.yml");
        pathWatcher.addExcludePattern(".*"); // Exclude hidden files
        
        // Watch services directory recursively
        Path servicesDir = Paths.get("services");
        pathWatcher.watchRecursively(servicesDir, this::handleServiceChange);
        
        pathWatcher.start("service-registry-watcher");
    }
    
    private void handleServiceChange(WatchEvent<?> event) {
        WatchEvent.Kind<?> kind = event.kind();
        Path path = (Path) event.context();
        
        switch (kind.name()) {
            case "ENTRY_CREATE", "ENTRY_MODIFY" -> reloadService(path);
            case "ENTRY_DELETE" -> removeService(path);
        }
    }
    
    private void reloadService(Path servicePath) {
        try {
            RegisteredService service = loadServiceFromFile(servicePath);
            serviceRegistry.save(service);
            log.info("Service reloaded: {}", service.getName());
        } catch (Exception e) {
            log.error("Failed to reload service from: {}", servicePath, e);
        }
    }
}

public class CompositeX509KeyManager implements X509KeyManager {
    
    private final List<X509KeyManager> keyManagers;
    private final KeySelectionStrategy selectionStrategy;
    
    // Constructors
    public CompositeX509KeyManager(List<X509KeyManager> keyManagers);
    public CompositeX509KeyManager(List<X509KeyManager> keyManagers, 
                                 KeySelectionStrategy strategy);
    
    // X509KeyManager implementation
    @Override
    public String[] getClientAliases(String keyType, Principal[] issuers);
    
    @Override
    public String chooseClientAlias(String[] keyType, Principal[] issuers, Socket socket);
    
    @Override
    public String[] getServerAliases(String keyType, Principal[] issuers);
    
    @Override
    public String chooseServerAlias(String keyType, Principal[] issuers, Socket socket);
    
    @Override
    public X509Certificate[] getCertificateChain(String alias);
    
    @Override
    public PrivateKey getPrivateKey(String alias);
    
    // Management methods
    public void addKeyManager(X509KeyManager keyManager);
    public void removeKeyManager(X509KeyManager keyManager);
    public List<X509KeyManager> getKeyManagers();
}

public class CompositeX509TrustManager implements X509TrustManager {
    
    private final List<X509TrustManager> trustManagers;
    private final TrustValidationStrategy validationStrategy;
    
    // Constructors
    public CompositeX509TrustManager(List<X509TrustManager> trustManagers);
    public CompositeX509TrustManager(List<X509TrustManager> trustManagers,
                                   TrustValidationStrategy strategy);
    
    // X509TrustManager implementation  
    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType) 
        throws CertificateException;
    
    @Override
    public void checkServerTrusted(X509Certificate[] chain, String authType) 
        throws CertificateException;
    
    @Override
    public X509Certificate[] getAcceptedIssuers();
    
    // Management methods
    public void addTrustManager(X509TrustManager trustManager);
    public void removeTrustManager(X509TrustManager trustManager);
    public List<X509TrustManager> getTrustManagers();
}

@UtilityClass
public class SSLUtils {
    
    // SSL context creation
    public static SSLContext createSSLContext(KeyManager[] keyManagers, 
                                            TrustManager[] trustManagers);
    
    public static SSLContext createSSLContext(KeyStore keyStore, 
                                            char[] keyStorePassword,
                                            KeyStore trustStore);
    
    // Certificate utilities
    public static KeyStore createKeyStore(String type);
    public static KeyStore loadKeyStore(InputStream inputStream, 
                                      char[] password, 
                                      String type);
    
    // Trust manager utilities
    public static X509TrustManager createTrustAllManager();
    public static X509TrustManager createDefaultTrustManager();
    
    // Hostname verification
    public static HostnameVerifier createPermissiveHostnameVerifier();
    public static HostnameVerifier createStrictHostnameVerifier();
    
    // SSL socket configuration
    public static void configureSSLSocket(SSLSocket socket, String[] protocols, String[] cipherSuites);
}

@Configuration
@EnableConfigurationProperties(SslProperties.class)
public class SslConfiguration {
    
    @Bean
    public SSLContext casSSLContext(SslProperties sslProperties) throws Exception {
        // Load multiple key stores
        List<X509KeyManager> keyManagers = new ArrayList<>();
        
        // Primary certificate
        KeyStore primaryKeyStore = SSLUtils.loadKeyStore(
            new FileInputStream(sslProperties.getPrimaryKeyStore()),
            sslProperties.getPrimaryKeyStorePassword().toCharArray(),
            "PKCS12"
        );
        KeyManagerFactory primaryKmf = KeyManagerFactory.getInstance("SunX509");
        primaryKmf.init(primaryKeyStore, sslProperties.getPrimaryKeyPassword().toCharArray());
        keyManagers.addAll(Arrays.asList((X509KeyManager[]) primaryKmf.getKeyManagers()));
        
        // Fallback certificate
        if (sslProperties.getFallbackKeyStore() != null) {
            KeyStore fallbackKeyStore = SSLUtils.loadKeyStore(
                new FileInputStream(sslProperties.getFallbackKeyStore()),
                sslProperties.getFallbackKeyStorePassword().toCharArray(),
                "PKCS12"
            );
            KeyManagerFactory fallbackKmf = KeyManagerFactory.getInstance("SunX509");
            fallbackKmf.init(fallbackKeyStore, sslProperties.getFallbackKeyPassword().toCharArray());
            keyManagers.addAll(Arrays.asList((X509KeyManager[]) fallbackKmf.getKeyManagers()));
        }
        
        // Create composite key manager
        CompositeX509KeyManager compositeKeyManager = new CompositeX509KeyManager(keyManagers);
        
        // Load trust stores
        List<X509TrustManager> trustManagers = new ArrayList<>();
        
        // System trust store
        trustManagers.add(SSLUtils.createDefaultTrustManager());
        
        // Custom trust store
        if (sslProperties.getTrustStore() != null) {
            KeyStore trustStore = SSLUtils.loadKeyStore(
                new FileInputStream(sslProperties.getTrustStore()),
                sslProperties.getTrustStorePassword().toCharArray(),
                "PKCS12"
            );
            TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");
            tmf.init(trustStore);
            trustManagers.addAll(Arrays.asList((X509TrustManager[]) tmf.getTrustManagers()));
        }
        
        // Create composite trust manager
        CompositeX509TrustManager compositeTrustManager = new CompositeX509TrustManager(trustManagers);
        
        // Create SSL context
        return SSLUtils.createSSLContext(
            new KeyManager[]{compositeKeyManager},
            new TrustManager[]{compositeTrustManager}
        );
    }
}

@Converter
public class MapToJsonAttributeConverter implements AttributeConverter<Map<String, Object>, String> {
    
    private final ObjectMapper objectMapper;
    
    public MapToJsonAttributeConverter();
    public MapToJsonAttributeConverter(ObjectMapper objectMapper);
    
    @Override
    public String convertToDatabaseColumn(Map<String, Object> attribute);
    
    @Override
    public Map<String, Object> convertToEntityAttribute(String dbData);
}

@Converter  
public class MultivaluedMapToJsonAttributeConverter 
    implements AttributeConverter<Map<String, List<Object>>, String> {
    
    @Override
    public String convertToDatabaseColumn(Map<String, List<Object>> attribute);
    
    @Override
    public Map<String, List<Object>> convertToEntityAttribute(String dbData);
}

@Entity
@Table(name = "user_profiles")
public class UserProfile {
    
    @Id
    private String userId;
    
    @Convert(converter = MapToJsonAttributeConverter.class)
    @Column(columnDefinition = "TEXT")
    private Map<String, Object> attributes;
    
    @Convert(converter = MultivaluedMapToJsonAttributeConverter.class)
    @Column(columnDefinition = "TEXT")
    private Map<String, List<Object>> preferences;
    
    // getters/setters
}

@Service
public class UserProfileService {
    
    public void updateUserAttributes(String userId, Map<String, Object> newAttributes) {
        UserProfile profile = userProfileRepository.findById(userId)
            .orElse(new UserProfile(userId));
        
        // Merge attributes
        Map<String, Object> existingAttributes = profile.getAttributes();
        if (existingAttributes == null) {
            existingAttributes = new HashMap<>();
        }
        existingAttributes.putAll(newAttributes);
        profile.setAttributes(existingAttributes);
        
        userProfileRepository.save(profile);
    }
}

public class CasReentrantLock extends ReentrantLock {
    
    private final String lockName;
    private final AtomicLong lockCount = new AtomicLong(0);
    private final AtomicLong contentionCount = new AtomicLong(0);
    
    // Constructors
    public CasReentrantLock(String lockName);
    public CasReentrantLock(String lockName, boolean fair);
    
    // Enhanced locking with monitoring
    @Override
    public void lock();
    
    @Override
    public boolean tryLock();
    
    @Override
    public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException;
    
    // Monitoring methods
    public String getLockName();
    public long getLockCount();
    public long getContentionCount();
    public LockStatistics getStatistics();
    
    // Debugging utilities
    public String getCurrentThreadInfo();
    public List<String> getQueuedThreadsInfo();
}

@Service
public class ThreadSafeTicketService {
    
    private final CasReentrantLock ticketLock = new CasReentrantLock("ticket-generation");
    private final AtomicLong ticketCounter = new AtomicLong(0);
    
    public String generateTicket(String serviceId) {
        ticketLock.lock();
        try {
            long ticketId = ticketCounter.incrementAndGet();
            String ticket = String.format("ST-%d-%s-%d", 
                ticketId, 
                serviceId, 
                System.currentTimeMillis()
            );
            
            log.debug("Generated ticket: {} (lock stats: {})", 
                ticket, ticketLock.getStatistics());
            
            return ticket;
            
        } finally {
            ticketLock.unlock();
        }
    }
    
    @EventListener
    public void onApplicationShutdown(ApplicationEvent event) {
        LockStatistics stats = ticketLock.getStatistics();
        log.info("Ticket generation lock statistics: {}", stats);
    }
}

public class VirtualThreadDelegate {
    
    // Virtual thread factory methods
    public ThreadFactory virtualThreadFactory();
    public ThreadFactory virtualThreadFactory(String threadNamePrefix);
    
    // Virtual thread creation
    public Thread newVirtualThread(String name, Runnable task);
    public Thread newVirtualThread(Runnable task);
    
    // Executor service with virtual threads
    public ExecutorService newVirtualThreadExecutor();
    public ExecutorService newVirtualThreadExecutor(String threadNamePrefix);
    
    // Utility methods
    public boolean isVirtualThreadsSupported();
    public CompletableFuture<Void> runAsync(Runnable task);
    public <T> CompletableFuture<T> supplyAsync(Supplier<T> supplier);
}

@Configuration
@ConditionalOnJavaVersion(JavaVersion.TWENTY_ONE)
public class VirtualThreadConfiguration {
    
    @Bean
    public VirtualThreadDelegate virtualThreadDelegate() {
        return new VirtualThreadDelegate();
    }
    
    @Bean
    @ConditionalOnProperty(name = "cas.virtual-threads.enabled", havingValue = "true")
    public ExecutorService virtualThreadExecutor(VirtualThreadDelegate delegate) {
        return delegate.newVirtualThreadExecutor("cas-virtual-");
    }
}

@Service
public class AsyncProcessingService {
    
    private final VirtualThreadDelegate virtualThreads;
    private final ExecutorService virtualExecutor;
    
    public CompletableFuture<ProcessingResult> processAsync(ProcessingRequest request) {
        if (virtualThreads.isVirtualThreadsSupported()) {
            return virtualThreads.supplyAsync(() -> processRequest(request));
        } else {
            return CompletableFuture.supplyAsync(() -> processRequest(request), virtualExecutor);
        }
    }
    
    public void processMultipleAsync(List<ProcessingRequest> requests) {
        List<CompletableFuture<Void>> futures = requests.stream()
            .map(request -> virtualThreads.runAsync(() -> processRequest(request)))
            .collect(Collectors.toList());
        
        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
            .thenRun(() -> log.info("All requests processed"));
    }
}

public class DefaultLogMessageSummarizer implements LogMessageSummarizer {
    
    private final Map<String, AtomicInteger> messageCounts;
    private final long summaryIntervalMs;
    
    public DefaultLogMessageSummarizer();
    public DefaultLogMessageSummarizer(long summaryIntervalMs);
    
    @Override
    public String summarize(String message);
    
    @Override
    public void reset();
    
    public Map<String, Integer> getMessageSummary();
}

public class DisabledLogMessageSummarizer implements LogMessageSummarizer {
    
    @Override
    public String summarize(String message);
    
    @Override  
    public void reset();
}

public interface ApplicationEntrypointInitializer {
    
    // Initialization methods
    void initialize();
    void initialize(String[] args);
    void initialize(ApplicationContext context);
    
    // Lifecycle methods
    default void beforeInitialization() {}
    default void afterInitialization() {}
    
    // Configuration
    int getOrder();
    boolean isEnabled();
}

@UtilityClass
public class ApplicationUtils {
    
    // Application information
    public static String getApplicationVersion();
    public static String getApplicationName();  
    public static Properties getApplicationProperties();
    
    // Runtime information
    public static RuntimeInformation getRuntimeInformation();
    public static MemoryInformation getMemoryInformation();
    public static SystemInformation getSystemInformation();
    
    // Configuration utilities
    public static boolean isProfileActive(String profile);
    public static String[] getActiveProfiles();
    public static Properties getEnvironmentProperties();
}