public abstract class SourceTask implements Task {
    ...
    /**
     * Determine the topic-specific settings for a new topic to which the {@link SourceRecord} {@link #poll() produced by this task}
     * are to be written. This method is called whenever Connect sees a topic in the {@link SourceRecord}s for the first time and when
     * verifies that the topic does not already exist.
     * <p>
     * By default this method simply returns the supplied initial settings. Implementations can override this method
     * to set the topic-specific settings that should be used when creating the new topic. The broker's own
     * topic-specific configuration settings will be used as defaults for any settings not set via the resulting object.
     * </p>
     *
     * @param settings the initial settings; never null
     * @param currentClusterSize the current number of brokers in the cluster, which can be used as an upper limit on the replication factor; always positive
     * @return the topic-specific settings; may be null if Connect should not attempt to create the topic (and potentially rely upon the broker auto-creating the topic)
     */
    public TopicSettings settingsForNewTopic(TopicSettings settings, int currentClusterSize) {
        return settings;
    }
}

/**
 * Topic-specific settings for a new topic.
 */
public interface TopicSettings {
    /**
     * The log cleanup policy for segments beyond the retention window
     */
    enum CleanupPolicy {
        /**
         * Ensures that Kafka will always retain at least the last known value for each message key within the log of
         * data for a single topic partition.
         */
        COMPACT,
        /**
         * Discard old log data after a fixed period of time or when the log reaches some predetermined size.
         */
        DELETE,
        /**
         * {@link #COMPACT Compact} to retain at least the last known value for each message key <i>and</i>
         * {@link #DELETE delete} messages after a period of time.
         */
        COMPACT_AND_DELETE
    }

    /**
     * Get the name of the topic.
     * @return the name of the topic
     */
    String name();

    /**
     * Get the number of partitions.
     * @return the number of partitions; always positive
     */
    int partitions();

    /**
     * Get the replication factor.
     * @return the replication factor; always positive
     */
    short replicationFactor();

    /**
     * Get the cleanup policy.
     * @return the cleanup policy; may be null if the broker's default setting for new topics is to be used
     */
    CleanupPolicy cleanupPolicy();

    /**
     * Get the maximum time the broker will retain a log before discarding old log segments to free up space.
     * This only applies when {@link #cleanupPolicy()} is set to {@link CleanupPolicy#DELETE}.
     *
     * @param unit the time unit in which the retention is defined; may not be null
     * @return the retention time, or -1 if there is no time limit; may be null if the broker's default setting is to be used
     */
    Long retentionTime(TimeUnit unit);

    /**
     * Get the maximum size a partition (which consists of log segments) can grow to before the broker discards old log segments
     * to free up space. This only applies when {@link #cleanupPolicy()} is set to {@link CleanupPolicy#DELETE}.
     *
     * @return the number of bytes, or -1 if there is no size limit; may be null if the broker's default setting is to be used
     */
    Long retentionBytes();

    /**
     * Get the minimum number of in-sync replicas that must exist for the topic to remain available.
     * @return the minimum number of in-sync replicas; may be null if the broker's default setting for new topics is to be used
     */
    Short minInSyncReplicas();

    /**
     * Get whether the broker is allowed to elect an unclean leader for the topic.
     * @return true if unclean leader election is allowed (potentially leading to data loss), or false otherwise;
     * may be null if the broker's default setting for new topics is to be used
     */
    Boolean uncleanLeaderElection();

    /**
     * Get the value for the named topic-specific configuration.
     * @param name the name of the topic-specific configuration
     * @return the configuration value, or null if the specified configuration has not been set
     */
    String config(String name);

    /**
     * Get the values for the set topic-specific configuration.
     * @return the map of configuration values keyed by configuration name; never null
     */
    Map<String, String> configs();

    /**
     * Specify the desired number of partitions for the topic.
     *
     * @param numPartitions the desired number of partitions; must be positive
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings partitions(int numPartitions);

    /**
     * Specify the desired replication factor for the topic.
     *
     * @param replicationFactor the desired replication factor; must be positive
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings replicationFactor(short replicationFactor);

    /**
     * Specify the desired cleanup policy for the topic.
     * @param policy the cleanup policy; may not be null
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings cleanupPolicy(CleanupPolicy policy);

    /**
     * Specify the maximum time the broker will retain a log before discarding old log segments to free up space.
     * This only applies when {@link #cleanupPolicy()} is set to {@link CleanupPolicy#DELETE}.
     *
     * @param time the retention time, or -1 if there is no time limit
     * @param unit the time unit; may not be null
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings retentionTime(long time, TimeUnit unit);

    /**
     * Specify the maximum size a partition (which consists of log segments) can grow to before the broker discards old log segments
     * to free up space. This only applies when {@link #cleanupPolicy()} is set to {@link CleanupPolicy#DELETE}.
     *
     * @param bytes the number of bytes, or -1 if there is no size limit
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings retentionBytes(long bytes);

    /**
     * Specify the minimum number of in-sync replicas required for this topic.
     *
     * @param minInSyncReplicas the minimum number of in-sync replicas allowed for the topic; must be positive
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings minInSyncReplicas(short minInSyncReplicas);

    /**
     * Specify whether the broker is allowed to elect a leader that was not an in-sync replica when no ISRs
     * are available.
     *
     * @param allow true if unclean leaders can be elected, or false if they are not allowed
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings uncleanLeaderElection(boolean allow);

    /**
     * Specify the name and value of the topic-specific setting for the topic, overwriting any corresponding property that was
     * previously set.
     *
     * @param configName the name of the topic-specific configuration property
     *                  @param configValue the value for the topic-specific configuration property
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings with(String configName, String configValue);

    /**
     * Specify the name and value of one or more topic-specific settings for the topic, overwriting any corresponding property that was
     * previously set.
     *
     * @param configs the desired topic configuration properties, or null if all existing properties should be cleared
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings with(Map<String, String> configs);

    /**
     * Clear all topic-specific settings from this definition. Unless other topic-specific settings are defined after this method is
     * called, the broker's default topic settings will be used when the topic is created.
     *
     * @return this settings object to allow methods to be chained; never null
     */
    TopicSettings clear();
}