Page History

package org.apache.kafka.streams;


/**
 * Represents all the query options that a user can provide to state what kind of stores it is expecting. The options would be whether a user would want to enable/disable stale stores* or whether it knows the list of partitions that it specifically wants to fetch. If this information is not provided the default behavior is to fetch the stores for all the partitions available on that instance* for that particular store name.
 * It contains a partition, which for a point queries can be populated from the  KeyQueryMetadata.
 */
public class StoreQueryParams<T> {

    private Integer partition;
    private boolean includeStaleStoresstaleStores;
    private final String storeName;
    private final QueryableStoreType<T> queryableStoreType;

    private StoreQueryParams(final String storeName, final QueryableStoreType<T>  queryableStoreType) {
        this.storeName = storeName;
        this.queryableStoreType = queryableStoreType;
    }

    public static <T> StoreQueryParams<T> fromNameAndType(final String storeName, final QueryableStoreType<T>  queryableStoreType) {
        return new <T> StoreQueryParams<T>(storeName, queryableStoreType);
    }

    /**
     * Get the {@link StoreQueryParams} with stale(standby, restoring) stores added via fetching the stores.
     *
     * @param partition   The specific integer partition to be fetched from the stores list by using {@link StoreQueryParams}.
     *
     * @return String storeName
     */
    public StoreQueryParams<T> withPartition(final Integer partition) {
        this.partition = partition;
        return this;
    }

    /**
     * Get the {@link StoreQueryParams} with stale(standby, restoring) stores added via fetching the stores.
     *
     * @return String storeName
     */
    public StoreQueryParams<T> withIncludeStaleStoresenableStaleStores() {
        this.includeStaleStoresstaleStores = true;
        return this;
    }

    /**
     * Get the partition to be used to fetch list of Queryable store from QueryableStoreProvider.
     * If the function returns null, it would mean that no specific partition has been requested so all the local partitions
     * for the store will be returned.
     *
     * @return Integer partition
     */
    public Integer partition() {
        return partition;
    }

    /**
     * Get the flag includeStaleStoresstaleStores. If true, include standbys and recovering stores along with running stores.
     *
     * @return boolean includeStaleStoresstaleStores
     */
    public boolean includeStaleStoresstaleStoresEnabled() {
        return includeStaleStoresstaleStores;
    }

    /**
     * Get the store name for which key is queried by the user.
     *
     * @return String storeName
     */
    public String storeName() {
        return storeName;
    }

    /**
     * Get the queryable store type for which key is queried by the user.
     *
     * @return QueryableStoreType queryableStoreType
     */
    public QueryableStoreType<T> queryableStoreType() {
        return queryableStoreType;
    }
}

   @Deprecated
 	public <T> T store(final String storeName, final QueryableStoreType<T> queryableStoreType) {
    }     

    /**
     * Get a facade wrapping the local {@link StateStore} instances with the provided {@link StoreQueryParams}.
     * StoreQueryParams need required parameters to be set, which are {@code storeName} and if
     * type is accepted by the provided {@link QueryableStoreType#accepts(StateStore) queryableStoreType}.
     * The optional parameters to the StoreQueryParams include {@code partition} and {@code includeStaleStoresstaleStores}.
     * The returned object can be used to query the {@link StateStore} instances.
     *
     * @param storeQueryParams    If StoreQueryParams.fromNameAndType(storeName, queryableStoreType).withPartition(int partition) is used, it allow queries on the specific partition irrespective if it is a standby
     *                            or a restoring replicas in addition to active ones.
     *                            If StoreQueryParams.fromNameAndType(storeName, queryableStoreType).withIncludeStaleStoresenableStaleStores() is used, it allow queries on standbys and restoring replicas in addition to active ones for all the local partitions on the instance.
     *                            If StoreQueryParams.fromNameAndType(storeName, queryableStoreType).withIncludeStaleStoresenableStaleStores().withPartition(int partition), it allow queries on the specific partition irrespective if it is a standby
     *                            or a restoring replicas in addition to active ones..
     *                            By default, if just storeQueryParams is used, it returns all the local partitions for the store which are in running state.
     * @param <T>                 return type
     * @return A facade wrapping the local {@link StateStore} instances
     * @throws InvalidStateStoreException if Kafka Streams is (re-)initializing or a store with {@code storeName} and
     * {@code queryableStoreType} doesn't exist
     */
    public <T> T store(final StoreQueryParams<T> storeQueryParams) {
    }