vvcephei commented on a change in pull request #11582:
URL: https://github.com/apache/kafka/pull/11582#discussion_r771520958
##########
File path:
streams/src/main/java/org/apache/kafka/streams/state/internals/StoreQueryUtils.java
##########
@@ -16,18 +16,78 @@
*/
package org.apache.kafka.streams.state.internals;
+import org.apache.kafka.common.utils.Bytes;
import org.apache.kafka.streams.processor.StateStore;
import org.apache.kafka.streams.processor.StateStoreContext;
import org.apache.kafka.streams.processor.api.RecordMetadata;
+import org.apache.kafka.streams.query.FailureReason;
+import org.apache.kafka.streams.query.KeyQuery;
import org.apache.kafka.streams.query.Position;
import org.apache.kafka.streams.query.PositionBound;
import org.apache.kafka.streams.query.Query;
import org.apache.kafka.streams.query.QueryResult;
+import org.apache.kafka.streams.state.KeyValueStore;
+import java.io.PrintWriter;
+import java.io.StringWriter;
import java.util.Map;
+import static org.apache.kafka.common.utils.Utils.mkEntry;
+import static org.apache.kafka.common.utils.Utils.mkMap;
+
public final class StoreQueryUtils {
+ /**
+ * a utility interface to facilitate stores' query dispatch logic,
+ * allowing them to generically store query execution logic as the values
+ * in a map.
+ */
+ @FunctionalInterface
+ public interface QueryHandler {
+ QueryResult<?> apply(
+ final Query<?> query,
+ final PositionBound positionBound,
+ final boolean collectExecutionInfo,
+ final StateStore store
+ );
+ }
+
+
+ @SuppressWarnings("unchecked")
+ private static final Map<Class<?>, QueryHandler> QUERY_HANDLER_MAP =
+ mkMap(
+ mkEntry(
+ PingQuery.class,
+ (query, positionBound, collectExecutionInfo, store) ->
QueryResult.forResult(true)
+ ),
+ mkEntry(KeyQuery.class,
+ (query, positionBound, collectExecutionInfo, store) -> {
+ if (store instanceof KeyValueStore) {
+ final KeyQuery<Bytes, byte[]> rawKeyQuery =
(KeyQuery<Bytes, byte[]>) query;
+ final KeyValueStore<Bytes, byte[]> keyValueStore =
+ (KeyValueStore<Bytes, byte[]>) store;
+ try {
+ final byte[] bytes =
keyValueStore.get(rawKeyQuery.getKey());
+ return QueryResult.forResult(bytes);
+ } catch (final Throwable t) {
Review comment:
Good point. It's fine to catch Throwables, but it's not fine to swallow
Errors, as I'm doing here.
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