Package org.apache.kafka.streams

Class TestOutputTopic<K,​V>

  • Type Parameters:
    K - the type of the record key
    V - the type of the record value
    public class TestOutputTopic<K,​V>
extends Object
    TestOutputTopic is used to read records from a topic in TopologyTestDriver. To use TestOutputTopic create a new instance via TopologyTestDriver.createOutputTopic(String, Deserializer, Deserializer). In actual test code, you can read record values, keys, KeyValue or TestRecord If you have multiple source topics, you need to create a TestOutputTopic for each.

    If you need to test key, value and headers, use readRecord() methods. Using readKeyValue() you get a KeyValue pair, and thus, don't get access to the record's timestamp or headers. Similarly using readValue() you only get the value of a record.

    Processing records

    
     private TestOutputTopic<String, Long> outputTopic;
      ...
     outputTopic = testDriver.createOutputTopic(OUTPUT_TOPIC, stringDeserializer, longDeserializer);
     ...
     assertThat(outputTopic.readValue()).isEqual(1);
    See Also:
    TopologyTestDriver

    • Method Detail

      • readValue

        public V readValue()
        Read one record from the output topic and return record's value.
        Returns:
        Next value for output topic.

      • readKeyValue

        public KeyValue<K,​V> readKeyValue()
        Read one record from the output topic and return its key and value as pair.
        Returns:
        Next output as KeyValue.

      • readRecord

        public TestRecord<K,​V> readRecord()
        Read one Record from output topic.
        Returns:
        Next output as TestRecord.

      • readRecordsToList

        public List<TestRecord<K,​V>> readRecordsToList()
        Read output to List. This method can be used if the result is considered a stream. If the result is considered a table, the list will contain all updated, ie, a key might be contained multiple times. If you are only interested in the last table update (ie, the final table state), you can use readKeyValuesToMap() instead.
        Returns:
        List of output.

      • readKeyValuesToMap

        public Map<K,​V> readKeyValuesToMap()
        Read output to map. This method can be used if the result is considered a table, when you are only interested in the last table update (ie, the final table state). If the result is considered a stream, you can use readRecordsToList() instead. The list will contain all updated, ie, a key might be contained multiple times. If the last update to a key is a delete/tombstone, the key will still be in the map (with null-value).
        Returns:
        Map of output by key.

      • readKeyValuesToList

        public List<KeyValue<K,​V>> readKeyValuesToList()
        Read all KeyValues from topic to List.
        Returns:
        List of output KeyValues.

      • readValuesToList

        public List<V> readValuesToList()
        Read all values from topic to List.
        Returns:
        List of output values.

      • getQueueSize

        public final long getQueueSize()
        Get size of unread record in the topic queue.
        Returns:
        size of topic queue.

      • isEmpty

        public final boolean isEmpty()
        Verify if the topic queue is empty.
        Returns:
        true if no more record in the topic queue.