content: /*
   * 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.StoreQueryParameters;
  import org.apache.kafka.streams.errors.InvalidStateStoreException;
  import org.apache.kafka.streams.errors.InvalidStateStorePartitionException;
  import org.apache.kafka.streams.state.QueryableStoreType;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * Provides a wrapper over multiple underlying {@link StateStoreProvider}s
   */
  @SuppressWarnings("rawtypes")
  public class WrappingStoreProvider implements StateStoreProvider {
  
      private final Collection<StreamThreadStateStoreProvider> storeProviders;
      private StoreQueryParameters storeQueryParameters;
  
      WrappingStoreProvider(final Collection<StreamThreadStateStoreProvider> storeProviders,
                            final StoreQueryParameters storeQueryParameters) {
          this.storeProviders = storeProviders;
          this.storeQueryParameters = storeQueryParameters;
      }
  
      //visible for testing
      public void setStoreQueryParameters(final StoreQueryParameters storeQueryParameters) {
          this.storeQueryParameters = storeQueryParameters;
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public <T> List<T> stores(final String storeName,
                                final QueryableStoreType<T> queryableStoreType) {
          final List<T> allStores = new ArrayList<>();
          for (final StreamThreadStateStoreProvider storeProvider : storeProviders) {
              final List<T> stores = storeProvider.stores(storeQueryParameters);
              if (!stores.isEmpty()) {
                  allStores.addAll(stores);
                  if (storeQueryParameters.partition() != null) {
                      break;
                  }
              }
          }
          if (allStores.isEmpty()) {
              if (storeQueryParameters.partition() != null) {
                  throw new InvalidStateStorePartitionException(
                          String.format("The specified partition %d for store %s does not exist.",
                                  storeQueryParameters.partition(),
                                  storeName));
              }
              throw new InvalidStateStoreException("The state store, " + storeName + ", may have migrated to another instance.");
          }
          return allStores;
      }
  }
  