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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.internals;
  
  import org.apache.kafka.streams.KeyValue;
  import org.apache.kafka.streams.StoreQueryParameters;
  import org.apache.kafka.streams.errors.InvalidStateStoreException;
  import org.apache.kafka.streams.kstream.Windowed;
  import org.apache.kafka.streams.kstream.internals.SessionWindow;
  import org.apache.kafka.streams.state.KeyValueIterator;
  import org.apache.kafka.streams.state.QueryableStoreType;
  import org.apache.kafka.streams.state.QueryableStoreTypes;
  import org.apache.kafka.streams.state.ReadOnlySessionStore;
  import org.apache.kafka.test.ReadOnlySessionStoreStub;
  import org.apache.kafka.test.StateStoreProviderStub;
  import org.apache.kafka.test.StreamsTestUtils;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import java.util.Arrays;
  import java.util.List;
  
  import static java.util.Collections.singletonList;
  import static org.apache.kafka.test.StreamsTestUtils.toListAndCloseIterator;
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.core.IsEqual.equalTo;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.fail;
  
  public class CompositeReadOnlySessionStoreTest {
  
      private final String storeName = "session-store";
      private final StateStoreProviderStub stubProviderOne = new StateStoreProviderStub(false);
      private final StateStoreProviderStub stubProviderTwo = new StateStoreProviderStub(false);
      private final ReadOnlySessionStoreStub<String, Long> underlyingSessionStore = new ReadOnlySessionStoreStub<>();
      private final ReadOnlySessionStoreStub<String, Long> otherUnderlyingStore = new ReadOnlySessionStoreStub<>();
      private CompositeReadOnlySessionStore<String, Long> sessionStore;
  
      @BeforeEach
      public void before() {
          stubProviderOne.addStore(storeName, underlyingSessionStore);
          stubProviderOne.addStore("other-session-store", otherUnderlyingStore);
          final QueryableStoreType<ReadOnlySessionStore<Object, Object>> queryableStoreType = QueryableStoreTypes.sessionStore();
  
          sessionStore = new CompositeReadOnlySessionStore<>(
              new WrappingStoreProvider(Arrays.asList(stubProviderOne, stubProviderTwo), StoreQueryParameters.fromNameAndType(storeName, queryableStoreType)),
              QueryableStoreTypes.sessionStore(), storeName);
      }
  
      @Test
      public void shouldFetchResultsFromUnderlyingSessionStore() {
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(0, 0)), 1L);
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(10, 10)), 2L);
  
          final List<KeyValue<Windowed<String>, Long>> results = toListAndCloseIterator(sessionStore.fetch("a"));
          assertEquals(Arrays.asList(KeyValue.pair(new Windowed<>("a", new SessionWindow(0, 0)), 1L),
                                     KeyValue.pair(new Windowed<>("a", new SessionWindow(10, 10)), 2L)),
                       results);
      }
  
      @Test
      public void shouldReturnEmptyIteratorIfNoData() {
          try (final KeyValueIterator<Windowed<String>, Long> result = sessionStore.fetch("b")) {
              assertFalse(result.hasNext());
          }
      }
  
      @Test
      public void shouldFindValueForKeyWhenMultiStores() {
          final ReadOnlySessionStoreStub<String, Long> secondUnderlying = new
                  ReadOnlySessionStoreStub<>();
          stubProviderTwo.addStore(storeName, secondUnderlying);
  
          final Windowed<String> keyOne = new Windowed<>("key-one", new SessionWindow(0, 0));
          final Windowed<String> keyTwo = new Windowed<>("key-two", new SessionWindow(0, 0));
          underlyingSessionStore.put(keyOne, 0L);
          secondUnderlying.put(keyTwo, 10L);
  
          final List<KeyValue<Windowed<String>, Long>> keyOneResults = toListAndCloseIterator(sessionStore.fetch("key-one"));
          final List<KeyValue<Windowed<String>, Long>> keyTwoResults = toListAndCloseIterator(sessionStore.fetch("key-two"));
  
          assertEquals(singletonList(KeyValue.pair(keyOne, 0L)), keyOneResults);
          assertEquals(singletonList(KeyValue.pair(keyTwo, 10L)), keyTwoResults);
      }
  
      @Test
      public void shouldNotGetValueFromOtherStores() {
          final Windowed<String> expectedKey = new Windowed<>("foo", new SessionWindow(0, 0));
          otherUnderlyingStore.put(new Windowed<>("foo", new SessionWindow(10, 10)), 10L);
          underlyingSessionStore.put(expectedKey, 1L);
  
          try (final KeyValueIterator<Windowed<String>, Long> result = sessionStore.fetch("foo")) {
              assertEquals(KeyValue.pair(expectedKey, 1L), result.next());
              assertFalse(result.hasNext());
          }
      }
  
      @Test
      public void shouldThrowInvalidStateStoreExceptionOnRebalance() {
          final QueryableStoreType<ReadOnlySessionStore<Object, Object>> queryableStoreType = QueryableStoreTypes.sessionStore();
          final CompositeReadOnlySessionStore<String, String> store =
              new CompositeReadOnlySessionStore<>(
                  new WrappingStoreProvider(singletonList(new StateStoreProviderStub(true)), StoreQueryParameters.fromNameAndType("whateva", queryableStoreType)),
                  QueryableStoreTypes.sessionStore(),
                  "whateva"
              );
  
          assertThrows(InvalidStateStoreException.class, () -> store.fetch("a"));
      }
  
      @Test
      public void shouldThrowInvalidStateStoreExceptionIfSessionFetchThrows() {
          underlyingSessionStore.setOpen(false);
          try {
              sessionStore.fetch("key");
              fail("Should have thrown InvalidStateStoreException with session store");
          } catch (final InvalidStateStoreException e) { }
      }
  
      @Test
      public void shouldThrowNullPointerExceptionIfFetchingNullKey() {
          assertThrows(NullPointerException.class, () -> sessionStore.fetch(null));
      }
  
      @Test
      public void shouldFetchKeyRangeAcrossStores() {
          final ReadOnlySessionStoreStub<String, Long> secondUnderlying = new
                  ReadOnlySessionStoreStub<>();
          stubProviderTwo.addStore(storeName, secondUnderlying);
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(0, 0)), 0L);
          secondUnderlying.put(new Windowed<>("b", new SessionWindow(0, 0)), 10L);
          final List<KeyValue<Windowed<String>, Long>> results = StreamsTestUtils.toListAndCloseIterator(sessionStore.fetch("a", "b"));
          assertThat(results, equalTo(Arrays.asList(
              KeyValue.pair(new Windowed<>("a", new SessionWindow(0, 0)), 0L),
              KeyValue.pair(new Windowed<>("b", new SessionWindow(0, 0)), 10L))));
      }
  
      @Test
      public void shouldFetchKeyRangeAcrossStoresWithNullKeyFrom() {
          final ReadOnlySessionStoreStub<String, Long> secondUnderlying = new
              ReadOnlySessionStoreStub<>();
          stubProviderTwo.addStore(storeName, secondUnderlying);
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(0, 0)), 0L);
          secondUnderlying.put(new Windowed<>("b", new SessionWindow(0, 0)), 10L);
          final List<KeyValue<Windowed<String>, Long>> results = StreamsTestUtils.toListAndCloseIterator(sessionStore.fetch(null, "b"));
          assertThat(results, equalTo(Arrays.asList(
              KeyValue.pair(new Windowed<>("a", new SessionWindow(0, 0)), 0L),
              KeyValue.pair(new Windowed<>("b", new SessionWindow(0, 0)), 10L))));
      }
  
      @Test
      public void shouldFetchKeyRangeAcrossStoresWithNullKeyTo() {
          final ReadOnlySessionStoreStub<String, Long> secondUnderlying = new
              ReadOnlySessionStoreStub<>();
          stubProviderTwo.addStore(storeName, secondUnderlying);
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(0, 0)), 0L);
          secondUnderlying.put(new Windowed<>("b", new SessionWindow(0, 0)), 10L);
          final List<KeyValue<Windowed<String>, Long>> results = StreamsTestUtils.toListAndCloseIterator(sessionStore.fetch("a", null));
          assertThat(results, equalTo(Arrays.asList(
              KeyValue.pair(new Windowed<>("a", new SessionWindow(0, 0)), 0L),
              KeyValue.pair(new Windowed<>("b", new SessionWindow(0, 0)), 10L))));
      }
  
      @Test
      public void shouldFetchKeyRangeAcrossStoresWithNullKeyFromKeyTo() {
          final ReadOnlySessionStoreStub<String, Long> secondUnderlying = new
              ReadOnlySessionStoreStub<>();
          stubProviderTwo.addStore(storeName, secondUnderlying);
          underlyingSessionStore.put(new Windowed<>("a", new SessionWindow(0, 0)), 0L);
          secondUnderlying.put(new Windowed<>("b", new SessionWindow(0, 0)), 10L);
          final List<KeyValue<Windowed<String>, Long>> results = StreamsTestUtils.toListAndCloseIterator(sessionStore.fetch(null, null));
          assertThat(results, equalTo(Arrays.asList(
              KeyValue.pair(new Windowed<>("a", new SessionWindow(0, 0)), 0L),
              KeyValue.pair(new Windowed<>("b", new SessionWindow(0, 0)), 10L))));
      }
  
      @Test
      public void shouldThrowNPEIfKeyIsNull() {
          assertThrows(NullPointerException.class, () -> underlyingSessionStore.fetch(null));
      }
  }
  