Transaction Management

public interface TransactionExecutorFactory extends org.apache.tephra.TransactionExecutorFactory {
    /**
     * Creates a new transaction executor with dynamic transaction context creation.
     * This allows for use of the factory with a DynamicDatasetCache.
     * 
     * @param txContextFactory the TransactionContextFactory for creating new TransactionContext
     * @return a new instance of TransactionExecutor
     */
    TransactionExecutor createExecutor(TransactionContextFactory txContextFactory);
}

public interface TransactionContextFactory {
    // Creates transaction contexts for dynamic dataset operations
    TransactionContext create();
}

// Standard Tephra transaction system client (from org.apache.tephra)
public interface TransactionSystemClient {
    Transaction startShort();
    Transaction startLong();
    boolean canCommit(Transaction tx, Collection<byte[]> changeIds);
    boolean commit(Transaction tx);
    void abort(Transaction tx);
    // ... other standard Tephra operations
}

// Transaction-aware interface for participating in transactions
public interface TransactionAware {
    void startTx(Transaction tx);
    Collection<byte[]> getTxChanges();
    boolean commitTx() throws Exception;
    void postTxCommit();
    boolean rollbackTx() throws Exception;
}

// Stream consumer with transaction support
public interface StreamConsumer extends Closeable, TransactionAware {
    // Transaction-aware stream consumption
    DequeInputDatum poll(long timeout, TimeUnit unit) throws InterruptedException;
    void consume(int maxEvents, StreamConsumerCallback callback) throws InterruptedException;
    
    // Consumer positioning and state
    void seek(StreamEventOffset offset);
    StreamEventOffset getPosition();
    
    // Transaction-aware state management
    @Override
    void startTx(Transaction tx);
    @Override
    Collection<byte[]> getTxChanges();
    @Override
    boolean commitTx() throws Exception;
    @Override
    void postTxCommit();
    @Override
    boolean rollbackTx() throws Exception;
}

// Stream consumer factory with transaction integration
public interface StreamConsumerFactory {
    StreamConsumer create(StreamId streamId, String namespace, ConsumerConfig config);
    StreamConsumer create(StreamId streamId, String namespace, ConsumerConfig config, 
                         StreamConsumerState startState);
}

// Consumer state management for transaction coordination
public interface ConsumerState<T> {
    T getState();
    void setState(T state);
    long getTimestamp();
}

// Consumer state store with transaction support
public interface ConsumerStateStore<S, T> extends TransactionAware {
    void configureState(S state, T initialState);
    ConsumerState<T> getState(S state);
    void saveState(S state, T stateValue, long timestamp);
    void removeState(S state);
}

public interface StreamAdmin {
    // Stream lifecycle management
    void create(StreamId streamId) throws Exception;
    void create(StreamId streamId, Map<String, String> properties) throws Exception;
    void drop(StreamId streamId) throws Exception;
    void truncate(StreamId streamId) throws Exception;
    
    // Stream configuration
    void updateConfig(StreamId streamId, StreamProperties properties) throws Exception;
    StreamProperties getConfig(StreamId streamId) throws Exception;
    
    // Stream metadata and statistics
    StreamSpecification getSpecification(StreamId streamId) throws Exception;
    List<StreamSpecification> listStreams(NamespaceId namespaceId) throws Exception;
    
    // Transaction coordination
    void upgrade() throws Exception;
    boolean exists(StreamId streamId) throws Exception;
}

// Access transaction system client (typically injected)
TransactionSystemClient txClient = // ... obtain instance

// Start a short transaction
Transaction tx = txClient.startShort();
try {
    // Perform transactional operations
    performDatasetOperations(tx);
    
    // Check if transaction can be committed
    Collection<byte[]> changeIds = getChangeIds();
    if (txClient.canCommit(tx, changeIds)) {
        // Commit the transaction
        boolean committed = txClient.commit(tx);
        if (committed) {
            System.out.println("Transaction committed successfully: " + tx.getTransactionId());
        }
    }
} catch (Exception e) {
    // Abort transaction on error
    txClient.abort(tx);
    System.out.println("Transaction aborted: " + tx.getTransactionId() + ", error: " + e.getMessage());
}

// Start a long transaction with timeout
Transaction longTx = txClient.startLong();
try {
    performLongRunningOperation(longTx);
    txClient.commitOrThrow(longTx);
} catch (TransactionFailureException e) {
    System.out.println("Long transaction failed: " + e.getMessage());
    txClient.abort(longTx);
}

// Create transaction executor with dataset instances
public void executeTransactionalOperation(TransactionExecutorFactory txFactory, 
                                        KeyValueTable dataset1, 
                                        KeyValueTable dataset2) {
    
    // Create executor with transaction-aware datasets
    TransactionExecutor executor = txFactory.createExecutor(Arrays.asList(dataset1, dataset2));
    
    // Execute transactional operation
    executor.execute(new TransactionExecutor.Subroutine() {
        @Override
        public void apply() throws Exception {
            // All operations within this block are transactional
            byte[] key = Bytes.toBytes("user123");
            
            // Read from first dataset
            byte[] userData = dataset1.read(key);
            
            if (userData != null) {
                // Process data and write to second dataset
                byte[] processedData = processUserData(userData);
                dataset2.write(key, processedData);
                
                // Update original dataset
                dataset1.write(key, updatedUserData(userData));
            }
            
            System.out.println("Transactional operation completed for key: " + Bytes.toString(key));
        }
    });
}

// Execute with custom transaction configuration
TransactionExecutor.Configuration config = TransactionExecutor.Configuration.builder()
    .setTimeout(30, TimeUnit.SECONDS)
    .setMaxRetries(3)
    .build();

TransactionExecutor customExecutor = txFactory.createExecutor(datasets, config);
customExecutor.execute(() -> {
    // Custom transaction logic with specific timeout and retry settings
});

// Create retrying transaction client for robust operations
RetryingLongTransactionSystemClient retryingClient = 
    RetryingLongTransactionSystemClient.builder()
        .setDelegate(originalTxClient)
        .setMaxRetries(5)
        .setRetryDelay(1000) // 1 second
        .setRetryStrategy(RetryStrategy.EXPONENTIAL_BACKOFF)
        .build();

// Use retrying client for critical operations
public void performCriticalTransactionalOperation() {
    Transaction tx = retryingClient.startLong();
    
    try {
        // Critical data operations that must succeed
        performCriticalDataMigration(tx);
        performCriticalIndexUpdate(tx);
        
        // The retrying client will automatically retry on transient failures
        retryingClient.commitOrThrow(tx);
        System.out.println("Critical operation completed successfully");
        
    } catch (TransactionFailureException e) {
        // Even with retries, the operation failed
        System.err.println("Critical operation failed after retries: " + e.getMessage());
        retryingClient.abort(tx);
        throw new RuntimeException("Critical operation could not be completed", e);
    }
}

// Transaction-aware stream consumer
public class TransactionalStreamProcessor {
    private final StreamConsumer streamConsumer;
    private final TransactionExecutorFactory txFactory;
    private final KeyValueTable outputDataset;
    
    public TransactionalStreamProcessor(StreamConsumer consumer, 
                                      TransactionExecutorFactory txFactory,
                                      KeyValueTable outputDataset) {
        this.streamConsumer = consumer;
        this.txFactory = txFactory;
        this.outputDataset = outputDataset;
    }
    
    public void processStreamTransactionally() {
        // Create executor with both stream consumer and output dataset
        TransactionExecutor executor = txFactory.createExecutor(
            Arrays.asList(streamConsumer, outputDataset));
        
        executor.execute(new TransactionExecutor.Subroutine() {
            @Override
            public void apply() throws Exception {
                // Consume events from stream within transaction
                streamConsumer.consume(100, new StreamConsumerCallback() {
                    @Override
                    public void onEvent(DequeInputDatum event, DequeInputDatum eventMetadata) throws Exception {
                        // Process stream event
                        byte[] processedData = processStreamEvent(event);
                        
                        // Write processed data to dataset within same transaction
                        String key = extractKey(event);
                        outputDataset.write(Bytes.toBytes(key), processedData);
                    }
                    
                    @Override
                    public void onFinish() throws Exception {
                        System.out.println("Batch processing completed");
                    }
                    
                    @Override
                    public void onError(Exception error) throws Exception {
                        System.err.println("Error processing stream events: " + error.getMessage());
                        throw error; // This will cause transaction rollback
                    }
                });
            }
        });
    }
}

// Stream consumer state management
public void manageStreamConsumerState(ConsumerStateStore<String, StreamEventOffset> stateStore,
                                     TransactionExecutorFactory txFactory) {
    
    String consumerId = "analytics-processor";
    StreamEventOffset initialOffset = new StreamEventOffset(0, 0);
    
    // Configure initial state
    TransactionExecutor executor = txFactory.createExecutor(Arrays.asList(stateStore));
    executor.execute(() -> {
        stateStore.configureState(consumerId, initialOffset);
    });
    
    // Process with state updates
    executor.execute(() -> {
        ConsumerState<StreamEventOffset> currentState = stateStore.getState(consumerId);
        StreamEventOffset currentOffset = currentState.getState();
        
        // Process events and update state
        StreamEventOffset newOffset = processEventsFromOffset(currentOffset);
        stateStore.saveState(consumerId, newOffset, System.currentTimeMillis());
        
        System.out.println("Updated consumer state from " + currentOffset + " to " + newOffset);
    });
}

// Nested transaction pattern for complex operations
public class NestedTransactionManager {
    private final TransactionExecutorFactory txFactory;
    
    public NestedTransactionManager(TransactionExecutorFactory txFactory) {
        this.txFactory = txFactory;
    }
    
    public void performNestedTransactionalOperations(List<KeyValueTable> datasets) {
        // Outer transaction for overall consistency
        TransactionExecutor outerExecutor = txFactory.createExecutor(datasets);
        
        outerExecutor.execute(() -> {
            // Perform outer transaction operations
            performOuterTransactionLogic(datasets);
            
            // Inner operations that might need their own transaction semantics
            for (KeyValueTable dataset : datasets) {
                performDatasetSpecificOperations(dataset);
            }
            
            // Final consistency check
            validateTransactionalConsistency(datasets);
        });
    }
    
    private void performDatasetSpecificOperations(KeyValueTable dataset) {
        // Dataset-specific operations within the outer transaction
        try {
            // Batch operations on single dataset
            performBatchOperations(dataset);
        } catch (Exception e) {
            System.err.println("Dataset operation failed: " + e.getMessage());
            throw new RuntimeException("Dataset operation failed", e);
        }
    }
}

// Transaction checkpoint pattern for long-running operations
public void performLongRunningTransactionalOperation(TransactionSystemClient txClient) {
    Transaction tx = txClient.startLong();
    
    try {
        // Phase 1
        performOperationPhase1(tx);
        
        // Checkpoint the transaction
        Transaction checkpointTx = txClient.checkpoint(tx);
        System.out.println("Transaction checkpointed: " + checkpointTx.getTransactionId());
        
        // Phase 2 using checkpointed transaction
        performOperationPhase2(checkpointTx);
        
        // Phase 3
        performOperationPhase3(checkpointTx);
        
        // Final commit
        txClient.commitOrThrow(checkpointTx);
        System.out.println("Long-running transaction completed successfully");
        
    } catch (Exception e) {
        txClient.abort(tx);
        System.err.println("Long-running transaction failed: " + e.getMessage());
        throw new RuntimeException("Long-running operation failed", e);
    }
}

// Transaction monitoring utility
public class TransactionMonitor {
    private final TransactionSystemClient txClient;
    
    public TransactionMonitor(TransactionSystemClient txClient) {
        this.txClient = txClient;
    }
    
    public void monitorTransactionSystem() {
        // Get transaction system status
        String status = txClient.getStatus();
        System.out.println("Transaction System Status: " + status);
        
        // Monitor transaction metrics
        printTransactionMetrics();
    }
    
    public void handleTransactionSystemRecovery() {
        try {
            // Reset transaction system state if needed
            System.out.println("Resetting transaction system state...");
            txClient.resetState();
            System.out.println("Transaction system state reset completed");
            
        } catch (Exception e) {
            System.err.println("Failed to reset transaction system: " + e.getMessage());
        }
    }
    
    public void createTransactionSnapshot() {
        try {
            InputStream snapshotStream = txClient.getSnapshotInputStream();
            
            // Save snapshot for backup/recovery
            saveSnapshotToFile(snapshotStream, "tx-snapshot-" + System.currentTimeMillis());
            System.out.println("Transaction snapshot created successfully");
            
        } catch (TransactionCouldNotTakeSnapshotException e) {
            System.err.println("Could not create transaction snapshot: " + e.getMessage());
        }
    }
}

// Core transaction types from Apache Tephra extended for CDAP
public interface Transaction extends org.apache.tephra.Transaction {
    // Transaction identification and state
    long getTransactionId();
    long getVisibilityUpperBound();
    Set<Long> getInvalids();
    Set<Long> getInProgress();
    
    // Transaction type and timeouts
    TransactionType getType();
    long getTimeout();
}

// Transaction executor configuration
public static class Configuration {
    public static Builder builder();
    
    public int getMaxRetries();
    public long getTimeoutMillis();
    public TimeUnit getTimeoutUnit();
    
    public static class Builder {
        public Builder setTimeout(long timeout, TimeUnit unit);
        public Builder setMaxRetries(int maxRetries);
        public Configuration build();
    }
}

// Transaction-aware interface for CDAP components
public interface TransactionAware extends org.apache.tephra.TransactionAware {
    @Override
    void startTx(Transaction tx);
    
    @Override
    Collection<byte[]> getTxChanges();
    
    @Override
    boolean commitTx() throws Exception;
    
    @Override
    void postTxCommit();
    
    @Override
    boolean rollbackTx() throws Exception;
    
    @Override
    String getTransactionAwareName();
}

// Stream event and consumer types
public interface DequeInputDatum {
    byte[] getData();
    Map<String, String> getHeaders();
    long getTimestamp();
}

public interface StreamConsumerCallback {
    void onEvent(DequeInputDatum event, DequeInputDatum eventMetadata) throws Exception;
    void onFinish() throws Exception;
    void onError(Exception error) throws Exception;
}

public final class StreamEventOffset {
    public long getGeneration();
    public long getOffset();
    
    public StreamEventOffset(long generation, long offset);
}

// Consumer configuration
public final class ConsumerConfig {
    public static Builder builder();
    
    public int getDequeueTimeout();
    public int getMaxDequeueSize();
    
    public static class Builder {
        public Builder setDequeueTimeout(int timeout);
        public Builder setMaxDequeueSize(int size);
        public ConsumerConfig build();
    }
}

// Retry strategy enumeration
public enum RetryStrategy {
    FIXED_DELAY,
    LINEAR_BACKOFF,
    EXPONENTIAL_BACKOFF,
    CUSTOM
}

// Exception types
public class TransactionFailureException extends Exception {
    public TransactionFailureException(String message);
    public TransactionFailureException(String message, Throwable cause);
}

public class TransactionNotInProgressException extends TransactionFailureException {
    public TransactionNotInProgressException(String message);
}

public class TransactionCouldNotTakeSnapshotException extends Exception {
    public TransactionCouldNotTakeSnapshotException(String message);
    public TransactionCouldNotTakeSnapshotException(String message, Throwable cause);
}