/*
* 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.internals;
import org.apache.kafka.streams.errors.InvalidStateStoreException;
import org.apache.kafka.streams.processor.StateStore;
import org.apache.kafka.streams.state.QueryableStoreType;
import java.util.ArrayList;
import java.util.List;
/**
* Provides a wrapper over multiple underlying {@link StateStoreProvider}s
*/
public class WrappingStoreProvider implements StateStoreProvider {
private final List<StateStoreProvider> storeProviders;
public WrappingStoreProvider(final List<StateStoreProvider> storeProviders) {
this.storeProviders = storeProviders;
}
/**
* Provides access to {@link org.apache.kafka.streams.processor.StateStore}s accepted
* by {@link QueryableStoreType#accepts(StateStore)}
* @param storeName name of the store
* @param type The {@link QueryableStoreType}
* @param <T> The type of the Store, for example, {@link org.apache.kafka.streams.state.ReadOnlyKeyValueStore}
* @return a List of all the stores with the storeName and are accepted by {@link QueryableStoreType#accepts(StateStore)}
*/
public <T> List<T> stores(final String storeName, QueryableStoreType<T> type) {
final List<T> allStores = new ArrayList<>();
for (StateStoreProvider provider : storeProviders) {
final List<T> stores =
provider.stores(storeName, type);
allStores.addAll(stores);
}
if (allStores.isEmpty()) {
throw new InvalidStateStoreException("the state store, " + storeName + ", may have migrated to another instance.");
}
return allStores;
}
}