org.apache.kafka.streams.processor.api

Class Record<K,V>

java.lang.Object

org.apache.kafka.streams.processor.api.Record<K,V>

Type Parameters:

K - The type of the key

V - The type of the value

public class Record<K,V>
extends Object

A data class representing an incoming record for processing in a Processor or a record to forward to downstream processors via ProcessorContext. This class encapsulates all the data attributes of a record: the key and value, but also the timestamp of the record and any record headers. This class is immutable, though the objects referenced in the attributes of this class may themselves be mutable.

Constructor Summary

Constructors

Constructor and Description
Record(K key, V value, long timestamp) Convenience constructor in case you do not wish to specify any headers.
Record(K key, V value, long timestamp, Headers headers) The full constructor, specifying all the attributes of the record.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
int	hashCode()
Headers	headers() The headers of the record.
K	key() The key of the record.
long	timestamp() The timestamp of the record.
String	toString()
V	value() The value of the record.
Record<K,V>	withHeaders(Headers headers) A convenient way to produce a new record if you only need to change the headers.
<NewK> Record<NewK,V>	withKey(NewK key) A convenient way to produce a new record if you only need to change the key.
Record<K,V>	withTimestamp(long timestamp) A convenient way to produce a new record if you only need to change the timestamp.
<NewV> Record<K,NewV>	withValue(NewV value) A convenient way to produce a new record if you only need to change the value.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Record

public Record(K key,
              V value,
              long timestamp,
              Headers headers)

The full constructor, specifying all the attributes of the record. Note: this constructor makes a copy of the headers argument. See ProcessorContext.forward(Record) for considerations around mutability of keys, values, and headers.

Parameters:

key - The key of the record. May be null.

value - The value of the record. May be null.

timestamp - The timestamp of the record. May not be negative.

headers - The headers of the record. May be null, which will cause subsequent calls to headers() to return a non-null, empty, Headers collection.

Throws:

IllegalArgumentException - if the timestamp is negative.

See Also:

ProcessorContext.forward(Record)

Record

public Record(K key,
              V value,
              long timestamp)

Convenience constructor in case you do not wish to specify any headers. Subsequent calls to headers() will return a non-null, empty, Headers collection.

Parameters:

key - The key of the record. May be null.

value - The value of the record. May be null.

timestamp - The timestamp of the record. May not be negative.

Throws:

IllegalArgumentException - if the timestamp is negative.

Method Detail

key

public K key()

The key of the record. May be null.

value

public V value()

The value of the record. May be null.

timestamp

public long timestamp()

The timestamp of the record. Will never be negative.

headers

public Headers headers()

The headers of the record. Never null.

withKey

public <NewK> Record<NewK,V> withKey(NewK key)

A convenient way to produce a new record if you only need to change the key. Copies the attributes of this record with the key replaced.

Type Parameters:

NewK - The type of the new record's key.

Parameters:

key - The key of the result record. May be null.

Returns:

A new Record instance with all the same attributes (except that the key is replaced).

withValue

public <NewV> Record<K,NewV> withValue(NewV value)

A convenient way to produce a new record if you only need to change the value. Copies the attributes of this record with the value replaced.

Type Parameters:

NewV - The type of the new record's value.

Parameters:

value - The value of the result record.

Returns:

A new Record instance with all the same attributes (except that the value is replaced).

withTimestamp

public Record<K,V> withTimestamp(long timestamp)

A convenient way to produce a new record if you only need to change the timestamp. Copies the attributes of this record with the timestamp replaced.

Parameters:

timestamp - The timestamp of the result record.

Returns:

A new Record instance with all the same attributes (except that the timestamp is replaced).

withHeaders

public Record<K,V> withHeaders(Headers headers)

A convenient way to produce a new record if you only need to change the headers. Copies the attributes of this record with the headers replaced. Also makes a copy of the provided headers. See ProcessorContext.forward(Record) for considerations around mutability of keys, values, and headers.

Parameters:

headers - The headers of the result record.

Returns:

A new Record instance with all the same attributes (except that the headers are replaced).

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object