Interactive queries in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a Kafka Streams application.

Kafka

KafkaStreams streams = new KafkaStreams(builder, [1]);

Drag options to blanks, or click blank then click option'

Aproperties

Bconfig

CstreamsConfig

Dsettings

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable name for configuration properties.

Passing an incorrect object type instead of Properties.

The KafkaStreams constructor requires a Properties object named config that contains the configuration settings.

2fill in blank

medium

Complete the code to query the local state store named "counts-store".

Kafka

ReadOnlyKeyValueStore<String, Long> store = streams.store(StoreQueryParameters.fromNameAndType("counts-store", [1]));

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AQueryableStoreTypes.timestampedKeyValueStore()

BQueryableStoreTypes.windowStore()

CQueryableStoreTypes.sessionStore()

DQueryableStoreTypes.keyValueStore()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong store type for querying.

Confusing window stores with key-value stores.

The keyValueStore() type is used to query a key-value store in Kafka Streams.

3fill in blank

hard

Fix the error in the code to get a value from the store by key.

Kafka

Long count = store.[1]("myKey");

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Aget

Bfetch

Cretrieve

DgetValue

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like fetch or retrieve.

Confusing with other API methods.

The correct method to get a value by key from a ReadOnlyKeyValueStore is get().

4fill in blank

hard

Fill both blanks to create a queryable store parameter for a window store named "window-store".

Kafka

StoreQueryParameters<String, Long> params = StoreQueryParameters.fromNameAndType("window-store", [1]); // store type

QueryableStoreType<WindowStore<String, Long>> storeType = [2];

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AQueryableStoreTypes.windowStore()

BQueryableStoreTypes.keyValueStore()

CQueryableStoreTypes.sessionStore()

DQueryableStoreTypes.timestampedKeyValueStore()

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing store types between key-value and window stores.

Using incorrect store type constants.

Both blanks require the window store type, which is QueryableStoreTypes.windowStore().

5fill in blank

hard

Fill all three blanks to create a map of key-value pairs from a store with a condition.

Kafka

Map<String, Long> result = new HashMap<>();
KeyValueIterator<String, Long> iter = store.all();
while (iter.hasNext()) {
    String key = iter.[1]().getKey();
    Long value = store.get(key);
    if (value [2] 10) {
        result.put(key, [3]);
    }
}
iter.close();

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Aiterator

B>

Cvalue

Dnext

Attempts:

3 left

💡 Hint

Common Mistakes

Using iterator() instead of next() on the iterator.

Using wrong comparison operators.

Putting the wrong variable into the map.

The all() method returns an iterator, so we use next() to get keys. The condition checks if the value is greater than 10, and then puts the value into the result map.