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.kstream.internals;
  
  import org.apache.kafka.common.metrics.Sensor;
  import org.apache.kafka.streams.kstream.ValueJoiner;
  import org.apache.kafka.streams.processor.api.ContextualProcessor;
  import org.apache.kafka.streams.processor.api.Processor;
  import org.apache.kafka.streams.processor.api.ProcessorContext;
  import org.apache.kafka.streams.processor.api.Record;
  import org.apache.kafka.streams.processor.api.RecordMetadata;
  import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
  import org.apache.kafka.streams.state.ValueAndTimestamp;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static org.apache.kafka.streams.processor.internals.RecordQueue.UNKNOWN;
  import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
  import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;
  
  class KTableKTableLeftJoin<K, V1, V2, VOut> extends KTableKTableAbstractJoin<K, V1, V2, VOut> {
      private static final Logger LOG = LoggerFactory.getLogger(KTableKTableLeftJoin.class);
  
      KTableKTableLeftJoin(final KTableImpl<K, ?, V1> table1,
                           final KTableImpl<K, ?, V2> table2,
                           final ValueJoiner<? super V1, ? super V2, ? extends VOut> joiner) {
          super(table1, table2, joiner);
      }
  
      @Override
      public Processor<K, Change<V1>, K, Change<VOut>> get() {
          return new KTableKTableLeftJoinProcessor(valueGetterSupplier2.get());
      }
  
      @Override
      public KTableValueGetterSupplier<K, VOut> view() {
          return new KTableKTableLeftJoinValueGetterSupplier(valueGetterSupplier1, valueGetterSupplier2);
      }
  
      private class KTableKTableLeftJoinValueGetterSupplier extends KTableKTableAbstractJoinValueGetterSupplier<K, VOut, V1, V2> {
  
          KTableKTableLeftJoinValueGetterSupplier(final KTableValueGetterSupplier<K, V1> valueGetterSupplier1,
                                                  final KTableValueGetterSupplier<K, V2> valueGetterSupplier2) {
              super(valueGetterSupplier1, valueGetterSupplier2);
          }
  
          public KTableValueGetter<K, VOut> get() {
              return new KTableKTableLeftJoinValueGetter(valueGetterSupplier1.get(), valueGetterSupplier2.get());
          }
      }
  
  
      private class KTableKTableLeftJoinProcessor extends ContextualProcessor<K, Change<V1>, K, Change<VOut>> {
  
          private final KTableValueGetter<K, V2> valueGetter;
          private Sensor droppedRecordsSensor;
  
          KTableKTableLeftJoinProcessor(final KTableValueGetter<K, V2> valueGetter) {
              this.valueGetter = valueGetter;
          }
  
          @Override
          public void init(final ProcessorContext<K, Change<VOut>> context) {
              super.init(context);
              droppedRecordsSensor = droppedRecordsSensor(
                  Thread.currentThread().getName(),
                  context.taskId().toString(),
                  (StreamsMetricsImpl) context.metrics()
              );
              valueGetter.init(context);
          }
  
          @Override
          public void process(final Record<K, Change<V1>> record) {
              // we do join iff keys are equal, thus, if key is null we cannot join and just ignore the record
              if (record.key() == null) {
                  if (context().recordMetadata().isPresent()) {
                      final RecordMetadata recordMetadata = context().recordMetadata().get();
                      LOG.warn(
                          "Skipping record due to null key. "
                              + "topic=[{}] partition=[{}] offset=[{}]",
                          recordMetadata.topic(), recordMetadata.partition(), recordMetadata.offset()
                      );
                  } else {
                      LOG.warn(
                          "Skipping record due to null key. Topic, partition, and offset not known."
                      );
                  }
                  droppedRecordsSensor.record();
                  return;
              }
  
              // drop out-of-order records from versioned tables (cf. KIP-914)
              if (useVersionedSemantics && !record.value().isLatest) {
                  LOG.info("Skipping out-of-order record from versioned table while performing table-table join.");
                  droppedRecordsSensor.record();
                  return;
              }
  
              VOut newValue = null;
              final long resultTimestamp;
              VOut oldValue = null;
  
              final ValueAndTimestamp<V2> valueAndTimestampRight = valueGetter.get(record.key());
              final V2 value2 = getValueOrNull(valueAndTimestampRight);
              final long timestampRight;
  
              if (value2 == null) {
                  if (record.value().newValue == null && record.value().oldValue == null) {
                      return;
                  }
                  timestampRight = UNKNOWN;
              } else {
                  timestampRight = valueAndTimestampRight.timestamp();
              }
  
              resultTimestamp = Math.max(record.timestamp(), timestampRight);
  
              if (record.value().newValue != null) {
                  newValue = joiner.apply(record.value().newValue, value2);
              }
  
              if (sendOldValues && record.value().oldValue != null) {
                  oldValue = joiner.apply(record.value().oldValue, value2);
              }
  
              context().forward(record.withValue(new Change<>(newValue, oldValue, record.value().isLatest)).withTimestamp(resultTimestamp));
          }
  
          @Override
          public void close() {
              valueGetter.close();
          }
      }
  
      private class KTableKTableLeftJoinValueGetter implements KTableValueGetter<K, VOut> {
  
          private final KTableValueGetter<K, V1> valueGetter1;
          private final KTableValueGetter<K, V2> valueGetter2;
  
          KTableKTableLeftJoinValueGetter(final KTableValueGetter<K, V1> valueGetter1,
                                          final KTableValueGetter<K, V2> valueGetter2) {
              this.valueGetter1 = valueGetter1;
              this.valueGetter2 = valueGetter2;
          }
  
          @Override
          public void init(final ProcessorContext<?, ?> context) {
              valueGetter1.init(context);
              valueGetter2.init(context);
          }
  
          @Override
          public ValueAndTimestamp<VOut> get(final K key) {
              final ValueAndTimestamp<V1> valueAndTimestamp1 = valueGetter1.get(key);
              final V1 value1 = getValueOrNull(valueAndTimestamp1);
  
              if (value1 != null) {
                  final ValueAndTimestamp<V2> valueAndTimestamp2 = valueGetter2.get(key);
                  final V2 value2 = getValueOrNull(valueAndTimestamp2);
                  final long resultTimestamp;
                  if (valueAndTimestamp2 == null) {
                      resultTimestamp = valueAndTimestamp1.timestamp();
                  } else {
                      resultTimestamp = Math.max(valueAndTimestamp1.timestamp(), valueAndTimestamp2.timestamp());
                  }
                  return ValueAndTimestamp.make(joiner.apply(value1, value2), resultTimestamp);
              } else {
                  return null;
              }
          }
  
          @Override
          public boolean isVersioned() {
              // even though we can derive a proper versioned result (assuming both parent value
              // getters are versioned), we choose not to since the output of a join of two
              // versioned tables today is not considered versioned (cf KIP-914)
              return false;
          }
  
          @Override
          public void close() {
              valueGetter1.close();
              valueGetter2.close();
          }
      }
  
  }
  