/*
* 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.processor.StateStore;
import org.apache.kafka.streams.state.internals.CompositeReadOnlyKeyValueStore;
import org.apache.kafka.streams.state.internals.CompositeReadOnlySessionStore;
import org.apache.kafka.streams.state.internals.CompositeReadOnlyWindowStore;
import org.apache.kafka.streams.state.internals.StateStoreProvider;
/**
* Provides access to the {@link QueryableStoreType}s provided with KafkaStreams. These
* can be used with {@link org.apache.kafka.streams.KafkaStreams#store(String, QueryableStoreType)}
* To access and query the {@link StateStore}s that are part of a Topology
*/
public class QueryableStoreTypes {
/**
* A {@link QueryableStoreType} that accepts {@link ReadOnlyKeyValueStore}
* @param <K> key type of the store
* @param <V> value type of the store
* @return {@link KeyValueStoreType}
*/
public static <K, V> QueryableStoreType<ReadOnlyKeyValueStore<K, V>> keyValueStore() {
return new KeyValueStoreType<>();
}
/**
* A {@link QueryableStoreType} that accepts {@link ReadOnlyWindowStore}
* @param <K> key type of the store
* @param <V> value type of the store
* @return {@link WindowStoreType}
*/
public static <K, V> QueryableStoreType<ReadOnlyWindowStore<K, V>> windowStore() {
return new WindowStoreType<>();
}
/**
* A {@link QueryableStoreType} that accepts {@link ReadOnlySessionStore}
* @param <K> key type of the store
* @param <V> value type of the store
* @return {@link SessionStoreType}
*/
public static <K, V> QueryableStoreType<ReadOnlySessionStore<K, V>> sessionStore() {
return new SessionStoreType<>();
}
private static abstract class QueryableStoreTypeMatcher<T> implements QueryableStoreType<T> {
private final Class matchTo;
QueryableStoreTypeMatcher(Class matchTo) {
this.matchTo = matchTo;
}
@SuppressWarnings("unchecked")
@Override
public boolean accepts(final StateStore stateStore) {
return matchTo.isAssignableFrom(stateStore.getClass());
}
}
private static class KeyValueStoreType<K, V> extends
QueryableStoreTypeMatcher<ReadOnlyKeyValueStore<K, V>> {
KeyValueStoreType() {
super(ReadOnlyKeyValueStore.class);
}
@Override
public ReadOnlyKeyValueStore<K, V> create(final StateStoreProvider storeProvider,
final String storeName) {
return new CompositeReadOnlyKeyValueStore<>(storeProvider, this, storeName);
}
}
private static class WindowStoreType<K, V> extends QueryableStoreTypeMatcher<ReadOnlyWindowStore<K, V>> {
WindowStoreType() {
super(ReadOnlyWindowStore.class);
}
@Override
public ReadOnlyWindowStore<K, V> create(final StateStoreProvider storeProvider,
final String storeName) {
return new CompositeReadOnlyWindowStore<>(storeProvider, this, storeName);
}
}
private static class SessionStoreType<K, V> extends QueryableStoreTypeMatcher<ReadOnlySessionStore<K, V>> {
SessionStoreType() {
super(ReadOnlySessionStore.class);
}
@Override
public ReadOnlySessionStore<K, V> create(final StateStoreProvider storeProvider, final String storeName) {
return new CompositeReadOnlySessionStore<>(storeProvider, this, storeName);
}
}
}