org.apache.kafka.streams

Class TestOutputTopic<K,V>

java.lang.Object

org.apache.kafka.streams.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 Summary

Modifier and Type	Method and Description
long	getQueueSize() Get size of unread record in the topic queue.
boolean	isEmpty() Verify if the topic queue is empty.
KeyValue<K,V>	readKeyValue() Read one record from the output topic and return its key and value as pair.
List<KeyValue<K,V>>	readKeyValuesToList() Read all KeyValues from topic to List.
Map<K,V>	readKeyValuesToMap() Read output to map.
TestRecord<K,V>	readRecord() Read one Record from output topic.
List<TestRecord<K,V>>	readRecordsToList() Read output to List.
V	readValue() Read one record from the output topic and return record's value.
List<V>	readValuesToList() Read all values from topic to List.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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.

toString

public String toString()

Overrides:

toString in class Object