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The Amazon Kinesis Client Library for Java enables Java developers to easily consume and process data from Amazon Kinesis.
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/*
 *  Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 *  Licensed under the Amazon Software License (the "License").
 *  You may not use this file except in compliance with the License.
 *  A copy of the License is located at
 *
 *  http://aws.amazon.com/asl/
 *
 *  or in the "license" file accompanying this file. This file is distributed
 *  on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 *  express or implied. See the License for the specific language governing
 *  permissions and limitations under the License.
 */

package software.amazon.kinesis.leases;

import java.util.Collection;
import java.util.List;
import java.util.UUID;

import software.amazon.kinesis.leases.dynamodb.DynamoDBLeaseCoordinator;
import software.amazon.kinesis.leases.exceptions.DependencyException;
import software.amazon.kinesis.leases.exceptions.InvalidStateException;
import software.amazon.kinesis.leases.exceptions.ProvisionedThroughputException;

/**
 *
 */
public interface LeaseCoordinator {
    /**
     * Initialize the lease coordinator (create the lease table if needed).
     * @throws DependencyException
     * @throws ProvisionedThroughputException
     */
    void initialize() throws ProvisionedThroughputException, DependencyException, IllegalStateException;

    /**
     * Start background LeaseHolder and LeaseTaker threads.
     * @throws ProvisionedThroughputException If we can't talk to DynamoDB due to insufficient capacity.
     * @throws InvalidStateException If the lease table doesn't exist
     * @throws DependencyException If we encountered exception taking to DynamoDB
     */
    void start() throws DependencyException, InvalidStateException, ProvisionedThroughputException;

    /**
     * Runs a single iteration of the lease taker - used by integration tests.
     *
     * @throws InvalidStateException
     * @throws DependencyException
     */
    void runLeaseTaker() throws DependencyException, InvalidStateException;

    /**
     * Runs a single iteration of the lease renewer - used by integration tests.
     *
     * @throws InvalidStateException
     * @throws DependencyException
     */
    void runLeaseRenewer() throws DependencyException, InvalidStateException;

    /**
     * @return true if this LeaseCoordinator is running
     */
    boolean isRunning();

    /**
     * @return workerIdentifier
     */
    String workerIdentifier();

    /**
     * @return {@link LeaseRefresher}
     */
    LeaseRefresher leaseRefresher();

    /**
     * @return currently held leases
     */
    Collection getAssignments();

    /**
     * @param leaseKey lease key to fetch currently held lease for
     *
     * @return deep copy of currently held Lease for given key, or null if we don't hold the lease for that key
     */
    Lease getCurrentlyHeldLease(String leaseKey);

    /**
     * Updates application-specific lease values in DynamoDB.
     *
     * @param lease lease object containing updated values
     * @param concurrencyToken obtained by calling Lease.concurrencyToken for a currently held lease
     *
     * @return true if update succeeded, false otherwise
     *
     * @throws InvalidStateException if lease table does not exist
     * @throws ProvisionedThroughputException if DynamoDB update fails due to lack of capacity
     * @throws DependencyException if DynamoDB update fails in an unexpected way
     */
    boolean updateLease(Lease lease, UUID concurrencyToken, String operation, String shardId)
            throws DependencyException, InvalidStateException, ProvisionedThroughputException;

    /**
     * Requests the cancellation of the lease taker.
     */
    void stopLeaseTaker();

    /**
     * Requests that renewals for the given lease are stopped.
     *
     * @param lease the lease to stop renewing.
     */
    void dropLease(Lease lease);

    /**
     * Stops background threads and waits for specific amount of time for all background tasks to complete.
     * If tasks are not completed after this time, method will shutdown thread pool forcefully and return.
     */
    void stop();

    /**
     * @return Current shard/lease assignments
     */
    List getCurrentAssignments();

    /**
     * @param writeCapacity The DynamoDB table used for tracking leases will be provisioned with the specified initial
     *        write capacity
     * @return LeaseCoordinator
     */
    DynamoDBLeaseCoordinator initialLeaseTableWriteCapacity(long writeCapacity);

    /**
     * @param readCapacity The DynamoDB table used for tracking leases will be provisioned with the specified initial
     *        read capacity
     * @return LeaseCoordinator
     */
    DynamoDBLeaseCoordinator initialLeaseTableReadCapacity(long readCapacity);
}