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.common.metrics.Sensor;
  import org.apache.kafka.common.serialization.Serde;
  import org.apache.kafka.common.utils.Bytes;
  import org.apache.kafka.common.utils.Time;
  import org.apache.kafka.streams.KeyValue;
  import org.apache.kafka.streams.errors.ProcessorStateException;
  import org.apache.kafka.streams.processor.internals.SerdeGetter;
  import org.apache.kafka.streams.query.KeyQuery;
  import org.apache.kafka.streams.query.PositionBound;
  import org.apache.kafka.streams.query.Query;
  import org.apache.kafka.streams.query.QueryConfig;
  import org.apache.kafka.streams.query.QueryResult;
  import org.apache.kafka.streams.query.RangeQuery;
  import org.apache.kafka.streams.query.ResultOrder;
  import org.apache.kafka.streams.query.TimestampedKeyQuery;
  import org.apache.kafka.streams.query.TimestampedRangeQuery;
  import org.apache.kafka.streams.query.internals.InternalQueryResultUtil;
  import org.apache.kafka.streams.state.KeyValueIterator;
  import org.apache.kafka.streams.state.KeyValueStore;
  import org.apache.kafka.streams.state.TimestampedKeyValueStore;
  import org.apache.kafka.streams.state.ValueAndTimestamp;
  
  import java.util.Map;
  import java.util.function.Function;
  
  import static org.apache.kafka.common.utils.Utils.mkEntry;
  import static org.apache.kafka.common.utils.Utils.mkMap;
  import static org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl.maybeMeasureLatency;
  
  /**
   * A Metered {@link TimestampedKeyValueStore} wrapper that is used for recording operation metrics, and hence its
   * inner KeyValueStore implementation do not need to provide its own metrics collecting functionality.
   * The inner {@link KeyValueStore} of this class is of type &lt;Bytes,byte[]&gt;, hence we use {@link Serde}s
   * to convert from &lt;K,ValueAndTimestamp&lt;V&gt&gt; to &lt;Bytes,byte[]&gt;
   * @param <K>
   * @param <V>
   */
  public class MeteredTimestampedKeyValueStore<K, V>
      extends MeteredKeyValueStore<K, ValueAndTimestamp<V>> 
      implements TimestampedKeyValueStore<K, V> {
  
      MeteredTimestampedKeyValueStore(final KeyValueStore<Bytes, byte[]> inner,
                                      final String metricScope,
                                      final Time time,
                                      final Serde<K> keySerde,
                                      final Serde<ValueAndTimestamp<V>> valueSerde) {
          super(inner, metricScope, time, keySerde, valueSerde);
      }
  
      @SuppressWarnings("rawtypes")
      private final Map<Class, StoreQueryUtils.QueryHandler> queryHandlers =
              mkMap(
                      mkEntry(
                              RangeQuery.class,
                              (query, positionBound, config, store) -> runRangeQuery(query, positionBound, config)
                      ),
                      mkEntry(
                              TimestampedRangeQuery.class,
                              (query, positionBound, config, store) -> runTimestampedRangeQuery(query, positionBound, config)
                      ),
                      mkEntry(
                              KeyQuery.class,
                              (query, positionBound, config, store) -> runKeyQuery(query, positionBound, config)
                      ),
                      mkEntry(
                              TimestampedKeyQuery.class,
                              (query, positionBound, config, store) -> runTimestampedKeyQuery(query, positionBound, config)
                      )
              );
  
      @SuppressWarnings("unchecked")
      @Override
      protected Serde<ValueAndTimestamp<V>> prepareValueSerdeForStore(final Serde<ValueAndTimestamp<V>> valueSerde, final SerdeGetter getter) {
          if (valueSerde == null) {
              return new ValueAndTimestampSerde<>((Serde<V>) getter.valueSerde());
          } else {
              return super.prepareValueSerdeForStore(valueSerde, getter);
          }
      }
  
      public RawAndDeserializedValue<V> getWithBinary(final K key) {
          try {
              return maybeMeasureLatency(() -> { 
                  final byte[] serializedValue = wrapped().get(keyBytes(key));
                  return new RawAndDeserializedValue<>(serializedValue, outerValue(serializedValue));
              }, time, getSensor);
          } catch (final ProcessorStateException e) {
              final String message = String.format(e.getMessage(), key);
              throw new ProcessorStateException(message, e);
          }
      }
  
      public boolean putIfDifferentValues(final K key,
                                          final ValueAndTimestamp<V> newValue,
                                          final byte[] oldSerializedValue) {
          try {
              return maybeMeasureLatency(
                  () -> {
                      final byte[] newSerializedValue = serdes.rawValue(newValue);
                      if (ValueAndTimestampSerializer.valuesAreSameAndTimeIsIncreasing(oldSerializedValue, newSerializedValue)) {
                          return false;
                      } else {
                          wrapped().put(keyBytes(key), newSerializedValue);
                          return true;
                      }
                  },
                  time,
                  putSensor
              );
          } catch (final ProcessorStateException e) {
              final String message = String.format(e.getMessage(), key, newValue);
              throw new ProcessorStateException(message, e);
          }
      }
  
      static class RawAndDeserializedValue<ValueType> {
          final byte[] serializedValue;
          final ValueAndTimestamp<ValueType> value;
          RawAndDeserializedValue(final byte[] serializedValue, final ValueAndTimestamp<ValueType> value) {
              this.serializedValue = serializedValue;
              this.value = value;
          }
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public <R> QueryResult<R> query(final Query<R> query,
                                      final PositionBound positionBound,
                                      final QueryConfig config) {
  
          final long start = time.nanoseconds();
          final QueryResult<R> result;
  
          final StoreQueryUtils.QueryHandler handler = queryHandlers.get(query.getClass());
          if (handler == null) {
              result = wrapped().query(query, positionBound, config);
              if (config.isCollectExecutionInfo()) {
                  result.addExecutionInfo(
                          "Handled in " + getClass() + " in " + (time.nanoseconds() - start) + "ns");
              }
          } else {
              result = (QueryResult<R>) handler.apply(
                      query,
                      positionBound,
                      config,
                      this
              );
              if (config.isCollectExecutionInfo()) {
                  result.addExecutionInfo(
                          "Handled in " + getClass() + " with serdes "
                                  + serdes + " in " + (time.nanoseconds() - start) + "ns");
              }
          }
          return result;
      }
  
  
  
      @SuppressWarnings("unchecked")
      private <R> QueryResult<R> runTimestampedKeyQuery(final Query<R> query,
                                                        final PositionBound positionBound,
                                                        final QueryConfig config) {
          final QueryResult<R> result;
          final TimestampedKeyQuery<K, V> typedKeyQuery = (TimestampedKeyQuery<K, V>) query;
          final KeyQuery<Bytes, byte[]> rawKeyQuery =
                  KeyQuery.withKey(keyBytes(typedKeyQuery.key()));
          final QueryResult<byte[]> rawResult =
                  wrapped().query(rawKeyQuery, positionBound, config);
          if (rawResult.isSuccess()) {
              final Function<byte[], ValueAndTimestamp<V>> deserializer = StoreQueryUtils.deserializeValue(serdes, wrapped());
              final ValueAndTimestamp<V> valueAndTimestamp = deserializer.apply(rawResult.getResult());
              final QueryResult<ValueAndTimestamp<V>> typedQueryResult =
                      InternalQueryResultUtil.copyAndSubstituteDeserializedResult(rawResult, valueAndTimestamp);
              result = (QueryResult<R>) typedQueryResult;
          } else {
              // the generic type doesn't matter, since failed queries have no result set.
              result = (QueryResult<R>) rawResult;
          }
          return result;
      }
  
      @SuppressWarnings("unchecked")
      private <R> QueryResult<R> runTimestampedRangeQuery(final Query<R> query,
                                                          final PositionBound positionBound,
                                                          final QueryConfig config) {
  
          final QueryResult<R> result;
          final TimestampedRangeQuery<K, V> typedQuery = (TimestampedRangeQuery<K, V>) query;
          RangeQuery<Bytes, byte[]> rawRangeQuery;
          final ResultOrder order = typedQuery.resultOrder();
          rawRangeQuery = RangeQuery.withRange(
                  keyBytes(typedQuery.lowerBound().orElse(null)),
                  keyBytes(typedQuery.upperBound().orElse(null))
          );
          if (order.equals(ResultOrder.DESCENDING)) {
              rawRangeQuery = rawRangeQuery.withDescendingKeys();
          }
          if (order.equals(ResultOrder.ASCENDING)) {
              rawRangeQuery = rawRangeQuery.withAscendingKeys();
          }
          final QueryResult<KeyValueIterator<Bytes, byte[]>> rawResult =
                  wrapped().query(rawRangeQuery, positionBound, config);
          if (rawResult.isSuccess()) {
              final KeyValueIterator<Bytes, byte[]> iterator = rawResult.getResult();
              final KeyValueIterator<K, ValueAndTimestamp<V>> resultIterator = (KeyValueIterator<K, ValueAndTimestamp<V>>) new MeteredTimestampedKeyValueStoreIterator(
                      iterator,
                      getSensor,
                      StoreQueryUtils.deserializeValue(serdes, wrapped()),
                      false
              );
              final QueryResult<KeyValueIterator<K, ValueAndTimestamp<V>>> typedQueryResult =
                      InternalQueryResultUtil.copyAndSubstituteDeserializedResult(
                              rawResult,
                              resultIterator
                      );
              result = (QueryResult<R>) typedQueryResult;
          } else {
              // the generic type doesn't matter, since failed queries have no result set.
              result = (QueryResult<R>) rawResult;
          }
          return result;
      }
  
      @SuppressWarnings("unchecked")
      private <R> QueryResult<R> runKeyQuery(final Query<R> query,
                                               final PositionBound positionBound,
                                               final QueryConfig config) {
          final QueryResult<R> result;
          final KeyQuery<K, V> typedKeyQuery = (KeyQuery<K, V>) query;
          final KeyQuery<Bytes, byte[]> rawKeyQuery =
                  KeyQuery.withKey(keyBytes(typedKeyQuery.getKey()));
          final QueryResult<byte[]> rawResult =
                  wrapped().query(rawKeyQuery, positionBound, config);
          if (rawResult.isSuccess()) {
              final Function<byte[], ValueAndTimestamp<V>> deserializer = StoreQueryUtils.deserializeValue(serdes, wrapped());
              final ValueAndTimestamp<V> valueAndTimestamp = deserializer.apply(rawResult.getResult());
              final V plainValue = valueAndTimestamp == null ? null : valueAndTimestamp.value();
              final QueryResult<V> typedQueryResult =
                      InternalQueryResultUtil.copyAndSubstituteDeserializedResult(rawResult, plainValue);
              result = (QueryResult<R>) typedQueryResult;
          } else {
              // the generic type doesn't matter, since failed queries have no result set.
              result = (QueryResult<R>) rawResult;
          }
          return result;
      }
  
      @SuppressWarnings("unchecked")
      private  <R> QueryResult<R> runRangeQuery(final Query<R> query,
                                                 final PositionBound positionBound,
                                                 final QueryConfig config) {
  
          final QueryResult<R> result;
          final RangeQuery<K, V> typedQuery = (RangeQuery<K, V>) query;
          RangeQuery<Bytes, byte[]> rawRangeQuery;
          final ResultOrder order = typedQuery.resultOrder();
          rawRangeQuery = RangeQuery.withRange(
                  keyBytes(typedQuery.getLowerBound().orElse(null)),
                  keyBytes(typedQuery.getUpperBound().orElse(null))
          );
          if (order.equals(ResultOrder.DESCENDING)) {
              rawRangeQuery = rawRangeQuery.withDescendingKeys();
          }
          if (order.equals(ResultOrder.ASCENDING)) {
              rawRangeQuery = rawRangeQuery.withAscendingKeys();
          }
          final QueryResult<KeyValueIterator<Bytes, byte[]>> rawResult =
                  wrapped().query(rawRangeQuery, positionBound, config);
          if (rawResult.isSuccess()) {
              final KeyValueIterator<Bytes, byte[]> iterator = rawResult.getResult();
              final KeyValueIterator<K, V> resultIterator = new MeteredTimestampedKeyValueStoreIterator(
                  iterator,
                  getSensor,
                  StoreQueryUtils.deserializeValue(serdes, wrapped()),
                  true
              );
              final QueryResult<KeyValueIterator<K, V>> typedQueryResult =
                      InternalQueryResultUtil.copyAndSubstituteDeserializedResult(
                              rawResult,
                              resultIterator
                      );
              result = (QueryResult<R>) typedQueryResult;
          } else {
              // the generic type doesn't matter, since failed queries have no result set.
              result = (QueryResult<R>) rawResult;
          }
          return result;
      }
  
      @SuppressWarnings("unchecked")
      private class MeteredTimestampedKeyValueStoreIterator implements KeyValueIterator<K, V>, MeteredIterator {
  
          private final KeyValueIterator<Bytes, byte[]> iter;
          private final Sensor sensor;
          private final long startNs;
          private final long startTimestampMs;
          private final Function<byte[], ValueAndTimestamp<V>> valueAndTimestampDeserializer;
  
          private final boolean returnPlainValue;
  
          private MeteredTimestampedKeyValueStoreIterator(final KeyValueIterator<Bytes, byte[]> iter,
                                                          final Sensor sensor,
                                                          final Function<byte[], ValueAndTimestamp<V>> valueAndTimestampDeserializer,
                                                          final boolean returnPlainValue) {
              this.iter = iter;
              this.sensor = sensor;
              this.valueAndTimestampDeserializer = valueAndTimestampDeserializer;
              this.startNs = time.nanoseconds();
              this.startTimestampMs = time.milliseconds();
              this.returnPlainValue = returnPlainValue;
              numOpenIterators.increment();
              openIterators.add(this);
          }
  
          @Override
          public long startTimestamp() {
              return startTimestampMs;
          }
  
          @Override
          public boolean hasNext() {
              return iter.hasNext();
          }
  
          @Override
          public KeyValue<K, V> next() {
              final KeyValue<Bytes, byte[]> keyValue = iter.next();
              if (returnPlainValue) {
                  final V plainValue = valueAndTimestampDeserializer.apply(keyValue.value).value();
                  return KeyValue.pair(
                          serdes.keyFrom(keyValue.key.get()), plainValue);
              }
              return (KeyValue<K, V>) KeyValue.pair(
                      serdes.keyFrom(keyValue.key.get()),
                      valueAndTimestampDeserializer.apply(keyValue.value));
          }
          @Override
          public void close() {
              try {
                  iter.close();
              } finally {
                  final long duration = time.nanoseconds() - startNs;
                  sensor.record(duration);
                  iteratorDurationSensor.record(duration);
                  numOpenIterators.decrement();
                  openIterators.remove(this);
              }
          }
  
          @Override
          public K peekNextKey() {
              return serdes.keyFrom(iter.peekNextKey().get());
          }
      }
  }
  