org.apache.kafka.streams.state.WindowStore Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License 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 org.apache.kafka.streams.state;
import org.apache.kafka.streams.errors.InvalidStateStoreException;
import org.apache.kafka.streams.internals.ApiUtils;
import org.apache.kafka.streams.kstream.Windowed;
import org.apache.kafka.streams.processor.StateStore;
import java.time.Instant;
import static org.apache.kafka.streams.internals.ApiUtils.prepareMillisCheckFailMsgPrefix;
/**
* Interface for storing the aggregated values of fixed-size time windows.
*
* Note, that the stores' physical key type is {@link Windowed Windowed<K>}.
*
* @param Type of keys
* @param Type of values
*/
public interface WindowStore extends StateStore, ReadOnlyWindowStore {
/**
* 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.
*
* @param key The key to associate the value to
* @param value The value; can be null
* @param windowStartTimestamp The timestamp of the beginning of the window to put the key/value into
* @throws InvalidStateStoreException if the store is not initialized
* @throws NullPointerException if the given key is {@code null}
*/
void put(K key, V value, long windowStartTimestamp);
/**
* 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 {@code 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.
*
* @param key the key to fetch
* @param timeFrom time range start (inclusive)
* @param timeTo time range end (inclusive)
* @return an iterator over key-value pairs {@code }
* @throws InvalidStateStoreException if the store is not initialized
* @throws NullPointerException if the given key is {@code null}
*/
// WindowStore keeps a long-based implementation of ReadOnlyWindowStore#fetch Instant-based
// if super#fetch is removed, keep this implementation as it serves PAPI Stores.
WindowStoreIterator fetch(K key, long timeFrom, long timeTo);
@Override
default WindowStoreIterator fetch(final K key,
final Instant timeFrom,
final Instant timeTo) throws IllegalArgumentException {
return fetch(
key,
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "timeTo")));
}
default WindowStoreIterator backwardFetch(final K key,
final long timeFrom,
final long timeTo) {
throw new UnsupportedOperationException();
}
@Override
default WindowStoreIterator backwardFetch(final K key,
final Instant timeFrom,
final Instant timeTo) throws IllegalArgumentException {
return backwardFetch(
key,
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "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.
*
* @param keyFrom the first key in the range
* A null value indicates a starting position from the first element in the store.
* @param keyTo the last key in the range
* A null value indicates that the range ends with the last element in the store.
* @param timeFrom time range start (inclusive)
* @param timeTo time range end (inclusive)
* @return an iterator over windowed key-value pairs {@code , value>}
* @throws InvalidStateStoreException if the store is not initialized
*/
// WindowStore keeps a long-based implementation of ReadOnlyWindowStore#fetch Instant-based
// if super#fetch is removed, keep this implementation as it serves PAPI Stores.
KeyValueIterator, V> fetch(K keyFrom, K keyTo, long timeFrom, long timeTo);
@Override
default KeyValueIterator, V> fetch(final K keyFrom,
final K keyTo,
final Instant timeFrom,
final Instant timeTo) throws IllegalArgumentException {
return fetch(
keyFrom,
keyTo,
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "timeTo")));
}
default KeyValueIterator, V> backwardFetch(final K keyFrom,
final K keyTo,
final long timeFrom,
final long timeTo) {
throw new UnsupportedOperationException();
}
@Override
default KeyValueIterator, V> backwardFetch(final K keyFrom,
final K keyTo,
final Instant timeFrom,
final Instant timeTo) throws IllegalArgumentException {
return backwardFetch(
keyFrom,
keyTo,
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "timeTo")));
}
/**
* Gets all the key-value pairs that belong to the windows within in the given time range.
*
* @param timeFrom the beginning of the time slot from which to search (inclusive)
* @param timeTo the end of the time slot from which to search (inclusive)
* @return an iterator over windowed key-value pairs {@code , value>}
* @throws InvalidStateStoreException if the store is not initialized
*/
// WindowStore keeps a long-based implementation of ReadOnlyWindowStore#fetch Instant-based
// if super#fetch is removed, keep this implementation as it serves PAPI Stores.
KeyValueIterator, V> fetchAll(long timeFrom, long timeTo);
@Override
default KeyValueIterator, V> fetchAll(final Instant timeFrom, final Instant timeTo) throws IllegalArgumentException {
return fetchAll(
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "timeTo")));
}
default KeyValueIterator, V> backwardFetchAll(final long timeFrom, final long timeTo) {
throw new UnsupportedOperationException();
}
@Override
default KeyValueIterator, V> backwardFetchAll(final Instant timeFrom, final Instant timeTo) throws IllegalArgumentException {
return backwardFetchAll(
ApiUtils.validateMillisecondInstant(timeFrom, prepareMillisCheckFailMsgPrefix(timeFrom, "timeFrom")),
ApiUtils.validateMillisecondInstant(timeTo, prepareMillisCheckFailMsgPrefix(timeTo, "timeTo")));
}
}