A KeyExtractor can extract the Pub/Sub Lite 'key' field used for message routing from a
PubsubMessage. It will by default use the ordering_key field directly for this if it exists.
An empty ByteString implies that the message should have no ordering key.
Static Fields
DEFAULT
publicstaticfinalKeyExtractorDEFAULT
An extractor that gets the routing key from the ordering key field.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[],[],null,["# Interface KeyExtractor (1.15.13)\n\nVersion latestkeyboard_arrow_down\n\n- [1.15.13 (latest)](/java/docs/reference/google-cloud-pubsublite/latest/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.15.12](/java/docs/reference/google-cloud-pubsublite/1.15.12/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.14.8](/java/docs/reference/google-cloud-pubsublite/1.14.8/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.13.8](/java/docs/reference/google-cloud-pubsublite/1.13.8/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.12.22](/java/docs/reference/google-cloud-pubsublite/1.12.22/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.11.2](/java/docs/reference/google-cloud-pubsublite/1.11.2/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.10.0](/java/docs/reference/google-cloud-pubsublite/1.10.0/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.9.4](/java/docs/reference/google-cloud-pubsublite/1.9.4/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.8.0](/java/docs/reference/google-cloud-pubsublite/1.8.0/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.7.1](/java/docs/reference/google-cloud-pubsublite/1.7.1/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.6.3](/java/docs/reference/google-cloud-pubsublite/1.6.3/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.5.5](/java/docs/reference/google-cloud-pubsublite/1.5.5/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor)\n- [1.4.12](/java/docs/reference/google-cloud-pubsublite/1.4.12/com.google.cloud.pubsublite.cloudpubsub.KeyExtractor) \n\n public interface KeyExtractor\n\nA KeyExtractor can extract the Pub/Sub Lite 'key' field used for message routing from a\nPubsubMessage. It will by default use the ordering_key field directly for this if it exists.\n\nAn empty ByteString implies that the message should have no ordering key.\n\nStatic Fields\n-------------\n\n### DEFAULT\n\n public static final KeyExtractor DEFAULT\n\nAn extractor that gets the routing key from the ordering key field.\n\nMethods\n-------\n\n### extractKey(PubsubMessage message)\n\n public abstract ByteString extractKey(PubsubMessage message)\n\nExtract the ByteString routing key from a PubsubMessage."]]
