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.processor.StateStore;
  import org.apache.kafka.streams.processor.TaskId;
  import org.apache.kafka.streams.processor.internals.StreamThread;
  import org.apache.kafka.streams.processor.internals.Task;
  import org.apache.kafka.streams.processor.internals.namedtopology.NamedTopologyStoreQueryParameters;
  import org.apache.kafka.streams.state.QueryableStoreType;
  import org.apache.kafka.streams.state.QueryableStoreTypes;
  import org.apache.kafka.streams.state.TimestampedKeyValueStore;
  import org.apache.kafka.streams.state.TimestampedWindowStore;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  
  public class StreamThreadStateStoreProvider {
  
      private final StreamThread streamThread;
  
      public StreamThreadStateStoreProvider(final StreamThread streamThread) {
          this.streamThread = streamThread;
      }
  
      @SuppressWarnings({"deprecation", "unchecked", "rawtypes"})
      public <T> List<T> stores(final StoreQueryParameters storeQueryParams) {
          final StreamThread.State state = streamThread.state();
          if (state == StreamThread.State.DEAD) {
              return Collections.emptyList();
          }
  
          final String storeName = storeQueryParams.storeName();
          final QueryableStoreType<T> queryableStoreType = storeQueryParams.queryableStoreType();
          final String topologyName = storeQueryParams instanceof NamedTopologyStoreQueryParameters ?
              ((NamedTopologyStoreQueryParameters) storeQueryParams).topologyName() :
              null;
  
          if (storeQueryParams.staleStoresEnabled() ? state.isAlive() : state == StreamThread.State.RUNNING) {
              final Collection<Task> tasks = storeQueryParams.staleStoresEnabled() ?
                      streamThread.readyOnlyAllTasks() : streamThread.readOnlyActiveTasks();
  
              if (storeQueryParams.partition() != null) {
                  for (final Task task : tasks) {
                      if (task.id().partition() == storeQueryParams.partition() &&
                          (topologyName == null || topologyName.equals(task.id().topologyName())) &&
                          task.store(storeName) != null &&
                          storeName.equals(task.store(storeName).name())) {
                          final T typedStore = validateAndCastStores(task.store(storeName), queryableStoreType, storeName, task.id());
                          return Collections.singletonList(typedStore);
                      }
                  }
                  return Collections.emptyList();
              } else {
                  final List<T> list = new ArrayList<>();
                  for (final Task task : tasks) {
                      final StateStore store = task.store(storeName);
                      if (store == null) {
                          // then this task doesn't have that store
                      } else {
                          final T typedStore = validateAndCastStores(store, queryableStoreType, storeName, task.id());
                          list.add(typedStore);
                      }
                  }
                  return list;
              }
          } else {
              throw new InvalidStateStoreException("Cannot get state store " + storeName + " because the stream thread is " +
                                                      state + ", not RUNNING" +
                                                      (storeQueryParams.staleStoresEnabled() ? " or REBALANCING" : ""));
          }
      }
  
      @SuppressWarnings("unchecked")
      private static <T> T validateAndCastStores(final StateStore store,
                                                 final QueryableStoreType<T> queryableStoreType,
                                                 final String storeName,
                                                 final TaskId taskId) {
          if (store == null) {
              throw new NullPointerException("Expected store not to be null at this point.");
          } else if (queryableStoreType.accepts(store)) {
              if (!store.isOpen()) {
                  throw new InvalidStateStoreException(
                          "Cannot get state store " + storeName + " for task " + taskId +
                              " because the store is not open. " +
                              "The state store may have migrated to another instance.");
              }
              if (store instanceof TimestampedKeyValueStore && queryableStoreType instanceof QueryableStoreTypes.KeyValueStoreType) {
                  return (T) new ReadOnlyKeyValueStoreFacade<>((TimestampedKeyValueStore<Object, Object>) store);
              } else if (store instanceof TimestampedWindowStore && queryableStoreType instanceof QueryableStoreTypes.WindowStoreType) {
                  return (T) new ReadOnlyWindowStoreFacade<>((TimestampedWindowStore<Object, Object>) store);
              } else {
                  return (T) store;
              }
          } else {
              throw new InvalidStateStoreException(
                  "Cannot get state store " + storeName +
                      " because the queryable store type [" + queryableStoreType.getClass() +
                      "] does not accept the actual store type [" + store.getClass() + "]."
              );
          }
      }
  }
  