Cluster Management

/**
 * Main interface for interacting with Flink clusters
 * @param <T> Type of cluster identifier
 */
public interface ClusterClient<T> extends AutoCloseable {
    /**
     * Returns the cluster identifier
     * @return Cluster ID of generic type T
     */
    T getClusterId();

    /**
     * Returns the Flink configuration for this cluster
     * @return Configuration instance
     */
    Configuration getFlinkConfiguration();

    /**
     * Shuts down the cluster
     */
    void shutDownCluster();

    /**
     * Returns the web interface URL for the cluster
     * @return URL string for web interface, may be null
     */
    String getWebInterfaceURL();

    /**
     * Lists all jobs running on the cluster
     * @return CompletableFuture containing collection of job status messages
     * @throws Exception if listing fails
     */
    CompletableFuture<Collection<JobStatusMessage>> listJobs() throws Exception;

    /**
     * Submits a job to the cluster
     * @param jobGraph JobGraph to submit
     * @return CompletableFuture containing assigned JobID
     */
    CompletableFuture<JobID> submitJob(JobGraph jobGraph);

    /**
     * Gets the status of a specific job
     * @param jobId ID of the job to check
     * @return CompletableFuture containing job status
     */
    CompletableFuture<JobStatus> getJobStatus(JobID jobId);

    /**
     * Requests the result of a job execution
     * @param jobId ID of the job
     * @return CompletableFuture containing job result
     */
    CompletableFuture<JobResult> requestJobResult(JobID jobId);

    /**
     * Gets job accumulators with default classloader
     * @param jobID ID of the job
     * @return CompletableFuture containing accumulator map
     */
    CompletableFuture<Map<String, Object>> getAccumulators(JobID jobID);

    /**
     * Gets job accumulators with specific classloader
     * @param jobID ID of the job
     * @param loader ClassLoader for deserialization
     * @return CompletableFuture containing accumulator map
     */
    CompletableFuture<Map<String, Object>> getAccumulators(JobID jobID, ClassLoader loader);

    /**
     * Cancels a running job
     * @param jobId ID of the job to cancel
     * @return CompletableFuture containing acknowledgment
     */
    CompletableFuture<Acknowledge> cancel(JobID jobId);

    /**
     * Cancels a job with savepoint
     * @param jobId ID of the job to cancel
     * @param savepointDirectory Directory to store the savepoint (nullable - uses default if null)
     * @return CompletableFuture containing savepoint path
     */
    CompletableFuture<String> cancelWithSavepoint(JobID jobId, @Nullable String savepointDirectory);

    /**
     * Stops a job with savepoint
     * @param jobId ID of the job to stop
     * @param advanceToEndOfEventTime Whether to advance to end of event time
     * @param savepointDirectory Directory to store the savepoint (nullable - uses default if null)
     * @return CompletableFuture containing savepoint path
     */
    CompletableFuture<String> stopWithSavepoint(
        JobID jobId, 
        boolean advanceToEndOfEventTime, 
        @Nullable String savepointDirectory);

    /**
     * Triggers a savepoint for a running job
     * @param jobId ID of the job
     * @param savepointDirectory Directory to store the savepoint (nullable - uses default if null)
     * @return CompletableFuture containing savepoint path
     */
    CompletableFuture<String> triggerSavepoint(JobID jobId, @Nullable String savepointDirectory);

    /**
     * Disposes a savepoint
     * @param savepointPath Path to the savepoint to dispose
     * @return CompletableFuture containing acknowledgment
     * @throws FlinkException if disposal fails
     */
    CompletableFuture<Acknowledge> disposeSavepoint(String savepointPath) throws FlinkException;

    /**
     * Sends a coordination request to an operator
     * @param jobId ID of the job containing the operator
     * @param operatorId ID of the operator
     * @param request Coordination request to send
     * @return CompletableFuture containing coordination response
     */
    CompletableFuture<CoordinationResponse> sendCoordinationRequest(
        JobID jobId, 
        OperatorID operatorId, 
        CoordinationRequest request);
}

import org.apache.flink.client.program.ClusterClient;
import org.apache.flink.client.deployment.StandaloneClusterDescriptor;
import org.apache.flink.client.deployment.StandaloneClusterId;

// Connect to standalone cluster
StandaloneClusterDescriptor descriptor = new StandaloneClusterDescriptor(config);
try (ClusterClient<StandaloneClusterId> client = 
         descriptor.retrieve(new StandaloneClusterId()).getClusterClient()) {
    
    // Submit job
    JobID jobId = client.submitJob(jobGraph).get();
    
    // Monitor job status
    JobStatus status = client.getJobStatus(jobId).get();
    System.out.println("Job status: " + status);
    
    // Trigger savepoint
    String savepointPath = client.triggerSavepoint(jobId, "/path/to/savepoints").get();
    System.out.println("Savepoint created at: " + savepointPath);
}

/**
 * Descriptor for cluster deployment and management
 * @param <T> Type of cluster identifier
 */
public interface ClusterDescriptor<T> extends AutoCloseable {
    /**
     * Returns a description of the cluster
     * @return String description of cluster capabilities
     */
    String getClusterDescription();

    /**
     * Retrieves an existing cluster
     * @param clusterId Identifier of the cluster to retrieve
     * @return ClusterClientProvider for the cluster
     * @throws ClusterRetrieveException if cluster cannot be retrieved
     */
    ClusterClientProvider<T> retrieve(T clusterId) throws ClusterRetrieveException;

    /**
     * Deploys a new session cluster
     * @param clusterSpecification Resource specification for the cluster
     * @return ClusterClientProvider for the deployed cluster
     * @throws ClusterDeploymentException if deployment fails
     */
    ClusterClientProvider<T> deploySessionCluster(ClusterSpecification clusterSpecification) 
        throws ClusterDeploymentException;

    /**
     * Deploys an application cluster
     * @param clusterSpecification Resource specification for the cluster
     * @param applicationConfiguration Application-specific configuration
     * @return ClusterClientProvider for the deployed cluster
     * @throws ClusterDeploymentException if deployment fails
     */
    ClusterClientProvider<T> deployApplicationCluster(
        ClusterSpecification clusterSpecification,
        ApplicationConfiguration applicationConfiguration) 
        throws ClusterDeploymentException;

    /**
     * Deploys a job-specific cluster
     * @param clusterSpecification Resource specification for the cluster
     * @param jobGraph Job graph to deploy
     * @param detached Whether to run in detached mode
     * @return ClusterClientProvider for the deployed cluster
     * @throws ClusterDeploymentException if deployment fails
     */
    ClusterClientProvider<T> deployJobCluster(
        ClusterSpecification clusterSpecification,
        JobGraph jobGraph,
        boolean detached) throws ClusterDeploymentException;

    /**
     * Kills an existing cluster
     * @param clusterId Identifier of the cluster to kill
     * @throws FlinkException if killing fails
     */
    void killCluster(T clusterId) throws FlinkException;
}

/**
 * Factory for creating cluster clients and descriptors
 * @param <ClusterID> Type of cluster identifier
 */
public interface ClusterClientFactory<ClusterID> {
    /**
     * Checks if this factory is compatible with the given configuration
     * @param configuration Flink configuration to check
     * @return true if compatible, false otherwise
     */
    boolean isCompatibleWith(Configuration configuration);

    /**
     * Creates a cluster descriptor for the given configuration
     * @param configuration Flink configuration
     * @return ClusterDescriptor instance
     */
    ClusterDescriptor<ClusterID> createClusterDescriptor(Configuration configuration);

    /**
     * Extracts cluster ID from configuration
     * @param configuration Flink configuration
     * @return Cluster ID instance
     */
    ClusterID getClusterId(Configuration configuration);

    /**
     * Creates cluster specification from configuration
     * @param configuration Flink configuration
     * @return ClusterSpecification instance
     */
    ClusterSpecification getClusterSpecification(Configuration configuration);
}

/**
 * Provider for cluster clients
 * @param <T> Type of cluster identifier
 */
public interface ClusterClientProvider<T> {
    /**
     * Gets the cluster client instance
     * @return ClusterClient instance for this cluster
     */
    ClusterClient<T> getClusterClient();

    /**
     * Closes the provider and releases resources
     */
    void close();
}

/**
 * Specification for cluster resources
 */
public class ClusterSpecification {
    /**
     * Gets the master/JobManager memory in MB
     * @return Memory in MB
     */
    public int getMasterMemoryMB();

    /**
     * Gets the TaskManager memory in MB
     * @return Memory in MB
     */
    public int getTaskManagerMemoryMB();

    /**
     * Gets the number of slots per TaskManager
     * @return Number of slots
     */
    public int getSlotsPerTaskManager();

    /**
     * Builder for creating ClusterSpecification instances
     */
    public static class ClusterSpecificationBuilder {
        /**
         * Sets master memory in MB
         * @param masterMemoryMB Memory in MB
         * @return This builder instance
         */
        public ClusterSpecificationBuilder setMasterMemoryMB(int masterMemoryMB);

        /**
         * Sets TaskManager memory in MB
         * @param taskManagerMemoryMB Memory in MB
         * @return This builder instance
         */
        public ClusterSpecificationBuilder setTaskManagerMemoryMB(int taskManagerMemoryMB);

        /**
         * Sets slots per TaskManager
         * @param slotsPerTaskManager Number of slots
         * @return This builder instance
         */
        public ClusterSpecificationBuilder setSlotsPerTaskManager(int slotsPerTaskManager);

        /**
         * Creates the ClusterSpecification
         * @return ClusterSpecification instance
         */
        public ClusterSpecification createClusterSpecification();
    }
}

import org.apache.flink.client.deployment.ClusterSpecification;

// Create cluster specification
ClusterSpecification spec = new ClusterSpecification.ClusterSpecificationBuilder()
    .setMasterMemoryMB(1024)
    .setTaskManagerMemoryMB(2048)
    .setSlotsPerTaskManager(4)
    .createClusterSpecification();

// Deploy session cluster
ClusterDescriptor<StandaloneClusterId> descriptor = 
    new StandaloneClusterDescriptor(config);
ClusterClientProvider<StandaloneClusterId> provider = 
    descriptor.deploySessionCluster(spec);

/**
 * Factory for standalone cluster clients
 */
public class StandaloneClientFactory implements ClusterClientFactory<StandaloneClusterId> {
    @Override
    public boolean isCompatibleWith(Configuration configuration);
    
    @Override
    public ClusterDescriptor<StandaloneClusterId> createClusterDescriptor(Configuration configuration);
    
    @Override
    public StandaloneClusterId getClusterId(Configuration configuration);
    
    @Override
    public ClusterSpecification getClusterSpecification(Configuration configuration);
}

/**
 * Descriptor for standalone clusters
 */
public class StandaloneClusterDescriptor implements ClusterDescriptor<StandaloneClusterId> {
    public StandaloneClusterDescriptor(Configuration flinkConfiguration);
    
    // Implements all ClusterDescriptor methods
}

/**
 * Identifier for standalone clusters
 */
public class StandaloneClusterId {
    public StandaloneClusterId();
}

/**
 * Client for mini clusters (testing/local development)
 */
public class MiniClusterClient implements ClusterClient<MiniClusterClient.MiniClusterId> {
    
    /**
     * Identifier for mini clusters
     */
    public static class MiniClusterId {
        // Mini cluster identifier implementation
    }
    
    // Implements all ClusterClient methods for mini cluster
}

public interface ClusterClientServiceLoader {
    Stream<ClusterClientFactory<ClusterID>> getClusterClientFactories();
}

public class DefaultClusterClientServiceLoader implements ClusterClientServiceLoader {
    @Override
    public Stream<ClusterClientFactory<ClusterID>> getClusterClientFactories();
}

public class JobStatusMessage {
    public JobID getJobId();
    public String getJobName();
    public JobStatus getJobStatus();
    public long getStartTime();
}

public interface Acknowledge {
    // Acknowledgment marker interface
}

public interface CoordinationRequest {
    // Base interface for coordination requests
}

public interface CoordinationResponse {
    // Base interface for coordination responses
}

public class OperatorID {
    public static OperatorID generate();
    public static OperatorID fromHexString(String hexString);
}

// Exception Types
public class ClusterDeploymentException extends FlinkException {
    public ClusterDeploymentException(String message);
    public ClusterDeploymentException(String message, Throwable cause);
}

public class ClusterRetrieveException extends FlinkException {
    public ClusterRetrieveException(String message);
    public ClusterRetrieveException(String message, Throwable cause);
}

public abstract class AbstractContainerizedClusterClientFactory<ClusterID> 
    implements ClusterClientFactory<ClusterID> {
    // Base class for containerized cluster client factories
}

public class ClusterClientJobClientAdapter<ClusterID> implements JobClient {
    public ClusterClientJobClientAdapter(
        ClusterClientProvider<ClusterID> clusterClientProvider,
        JobID jobId,
        ClassLoader userCodeClassloader);
    
    // Implements JobClient interface by adapting ClusterClient calls
}