Package org.apache.kafka.streams.state

Interface WindowStore<K,V>

Type Parameters:
K - Type of keys
V - Type of values
All Superinterfaces:
ReadOnlyWindowStore<K,V>, StateStore
All Known Subinterfaces:
TimestampedWindowStore<K,V>
public interface WindowStore<K,V> extends StateStore, ReadOnlyWindowStore<K,V>
Interface for storing the aggregated values of fixed-size time windows.

Note, that the stores' physical key type is Windowed<K>.

  • Method Details

    • put

      void put(K key, V value, long windowStartTimestamp)
      Put a key-value pair into the window with given window start timestamp

      If serialized value bytes are null it is interpreted as delete. Note that deletes will be ignored in the case of an underlying store that retains duplicates.

      Parameters:
      key - The key to associate the value to
      value - The value; can be null
      windowStartTimestamp - The timestamp of the beginning of the window to put the key/value into
      Throws:
      NullPointerException - if the given key is null

    • fetch

      WindowStoreIterator<V> fetch(K key, long timeFrom, long timeTo)
      Get all the key-value pairs with the given key and the time range from all the existing windows.

      This iterator must be closed after use.

      The time range is inclusive and applies to the starting timestamp of the window. For example, if we have the following windows: 

       +-------------------------------+
 |  key  | start time | end time |
 +-------+------------+----------+
 |   A   |     10     |    20    |
 +-------+------------+----------+
 |   A   |     15     |    25    |
 +-------+------------+----------+
 |   A   |     20     |    30    |
 +-------+------------+----------+
 |   A   |     25     |    35    |
 +--------------------------------
      And we call store.fetch("A", 10, 20) then the results will contain the first three windows from the table above, i.e., all those where 10 <= start time <= 20.

      For each key, the iterator guarantees ordering of windows, starting from the oldest/earliest available window to the newest/latest window.

      Parameters:
      key - the key to fetch
      timeFrom - time range start (inclusive)
      timeTo - time range end (inclusive)
      Returns:
      an iterator over key-value pairs <timestamp, value>
      Throws:
      InvalidStateStoreException - if the store is not initialized
      NullPointerException - if the given key is null

    • fetch

      default WindowStoreIterator<V> fetch(K key, Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Get all the key-value pairs with the given key and the time range from all the existing windows.

      This iterator must be closed after use.

      The time range is inclusive and applies to the starting timestamp of the window. For example, if we have the following windows: 

       +-------------------------------+
 |  key  | start time | end time |
 +-------+------------+----------+
 |   A   |     10     |    20    |
 +-------+------------+----------+
 |   A   |     15     |    25    |
 +-------+------------+----------+
 |   A   |     20     |    30    |
 +-------+------------+----------+
 |   A   |     25     |    35    |
 +--------------------------------
      And we call store.fetch("A", Instant.ofEpochMilli(10), Instant.ofEpochMilli(20)) then the results will contain the first three windows from the table above, i.e., all those where 10 <= start time <= 20.

      For each key, the iterator guarantees ordering of windows, starting from the oldest/earliest available window to the newest/latest window.

      Specified by:
      fetch in interface ReadOnlyWindowStore<K,V>
      Parameters:
      key - the key to fetch
      timeFrom - time range start (inclusive), where iteration starts.
      timeTo - time range end (inclusive), where iteration ends.
      Returns:
      an iterator over key-value pairs <timestamp, value>, from beginning to end of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds

    • backwardFetch

      default WindowStoreIterator<V> backwardFetch(K key, long timeFrom, long timeTo)

    • backwardFetch

      default WindowStoreIterator<V> backwardFetch(K key, Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Get all the key-value pairs with the given key and the time range from all the existing windows in backward order with respect to time (from end to beginning of time).

      This iterator must be closed after use.

      The time range is inclusive and applies to the starting timestamp of the window. For example, if we have the following windows: 

       +-------------------------------+
 |  key  | start time | end time |
 +-------+------------+----------+
 |   A   |     10     |    20    |
 +-------+------------+----------+
 |   A   |     15     |    25    |
 +-------+------------+----------+
 |   A   |     20     |    30    |
 +-------+------------+----------+
 |   A   |     25     |    35    |
 +--------------------------------
      And we call store.backwardFetch("A", Instant.ofEpochMilli(10), Instant.ofEpochMilli(20)) then the results will contain the first three windows from the table above in backward order, i.e., all those where 10 <= start time <= 20.

      For each key, the iterator guarantees ordering of windows, starting from the newest/latest available window to the oldest/earliest window.

      Specified by:
      backwardFetch in interface ReadOnlyWindowStore<K,V>
      Parameters:
      key - the key to fetch
      timeFrom - time range start (inclusive), where iteration ends.
      timeTo - time range end (inclusive), where iteration starts.
      Returns:
      an iterator over key-value pairs <timestamp, value>, from end to beginning of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds

    • fetch

      KeyValueIterator<Windowed<K>,V> fetch(K keyFrom, K keyTo, long timeFrom, long timeTo)
      Get all the key-value pairs in the given key range and time range from all the existing windows.

      This iterator must be closed after use.

      Parameters:
      keyFrom - the first key in the range A null value indicates a starting position from the first element in the store.
      keyTo - the last key in the range A null value indicates that the range ends with the last element in the store.
      timeFrom - time range start (inclusive)
      timeTo - time range end (inclusive)
      Returns:
      an iterator over windowed key-value pairs <Windowed<K>, value>
      Throws:
      InvalidStateStoreException - if the store is not initialized

    • fetch

      default KeyValueIterator<Windowed<K>,V> fetch(K keyFrom, K keyTo, Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Get all the key-value pairs in the given key range and time range from all the existing windows.

      This iterator must be closed after use.

      Specified by:
      fetch in interface ReadOnlyWindowStore<K,V>
      Parameters:
      keyFrom - the first key in the range A null value indicates a starting position from the first element in the store.
      keyTo - the last key in the range A null value indicates that the range ends with the last element in the store.
      timeFrom - time range start (inclusive), where iteration starts.
      timeTo - time range end (inclusive), where iteration ends.
      Returns:
      an iterator over windowed key-value pairs <Windowed<K>, value>, from beginning to end of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds

    • backwardFetch

      default KeyValueIterator<Windowed<K>,V> backwardFetch(K keyFrom, K keyTo, long timeFrom, long timeTo)

    • backwardFetch

      default KeyValueIterator<Windowed<K>,V> backwardFetch(K keyFrom, K keyTo, Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Get all the key-value pairs in the given key range and time range from all the existing windows in backward order with respect to time (from end to beginning of time).

      This iterator must be closed after use.

      Specified by:
      backwardFetch in interface ReadOnlyWindowStore<K,V>
      Parameters:
      keyFrom - the first key in the range A null value indicates a starting position from the first element in the store.
      keyTo - the last key in the range A null value indicates that the range ends with the last element in the store.
      timeFrom - time range start (inclusive), where iteration ends.
      timeTo - time range end (inclusive), where iteration starts.
      Returns:
      an iterator over windowed key-value pairs <Windowed<K>, value>, from end to beginning of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds

    • fetchAll

      KeyValueIterator<Windowed<K>,V> fetchAll(long timeFrom, long timeTo)
      Gets all the key-value pairs that belong to the windows within in the given time range.
      Parameters:
      timeFrom - the beginning of the time slot from which to search (inclusive)
      timeTo - the end of the time slot from which to search (inclusive)
      Returns:
      an iterator over windowed key-value pairs <Windowed<K>, value>
      Throws:
      InvalidStateStoreException - if the store is not initialized

    • fetchAll

      default KeyValueIterator<Windowed<K>,V> fetchAll(Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Gets all the key-value pairs that belong to the windows within in the given time range.
      Specified by:
      fetchAll in interface ReadOnlyWindowStore<K,V>
      Parameters:
      timeFrom - the beginning of the time slot from which to search (inclusive), where iteration starts.
      timeTo - the end of the time slot from which to search (inclusive), where iteration ends.
      Returns:
      an iterator over windowed key-value pairs <Windowed<K>, value>, from beginning to end of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds

    • backwardFetchAll

      default KeyValueIterator<Windowed<K>,V> backwardFetchAll(long timeFrom, long timeTo)

    • backwardFetchAll

      default KeyValueIterator<Windowed<K>,V> backwardFetchAll(Instant timeFrom, Instant timeTo) throws IllegalArgumentException
      Description copied from interface: ReadOnlyWindowStore
      Gets all the key-value pairs that belong to the windows within in the given time range in backward order with respect to time (from end to beginning of time).
      Specified by:
      backwardFetchAll in interface ReadOnlyWindowStore<K,V>
      Parameters:
      timeFrom - the beginning of the time slot from which to search (inclusive), where iteration ends.
      timeTo - the end of the time slot from which to search (inclusive), where iteration starts.
      Returns:
      an backward iterator over windowed key-value pairs <Windowed<K>, value>, from end to beginning of time.
      Throws:
      IllegalArgumentException - if duration is negative or can't be represented as long milliseconds