Examples with Transformer org.apache.kafka.streams.kstream.Transformer used on opensource projects

Example 1 with Transformer

use of org.apache.kafka.streams.kstream.Transformer in project kafka by apache.

the class KStreamTransformTest method testTransform.

@Test
public void testTransform() {
    KStreamBuilder builder = new KStreamBuilder();
    TransformerSupplier<Number, Number, KeyValue<Integer, Integer>> transformerSupplier = new TransformerSupplier<Number, Number, KeyValue<Integer, Integer>>() {

        public Transformer<Number, Number, KeyValue<Integer, Integer>> get() {
            return new Transformer<Number, Number, KeyValue<Integer, Integer>>() {

                private int total = 0;

                @Override
                public void init(ProcessorContext context) {
                }

                @Override
                public KeyValue<Integer, Integer> transform(Number key, Number value) {
                    total += value.intValue();
                    return KeyValue.pair(key.intValue() * 2, total);
                }

                @Override
                public KeyValue<Integer, Integer> punctuate(long timestamp) {
                    return KeyValue.pair(-1, (int) timestamp);
                }

                @Override
                public void close() {
                }
            };
        }
    };
    final int[] expectedKeys = { 1, 10, 100, 1000 };
    MockProcessorSupplier<Integer, Integer> processor = new MockProcessorSupplier<>();
    KStream<Integer, Integer> stream = builder.stream(intSerde, intSerde, topicName);
    stream.transform(transformerSupplier).process(processor);
    driver = new KStreamTestDriver(builder);
    for (int expectedKey : expectedKeys) {
        driver.process(topicName, expectedKey, expectedKey * 10);
    }
    driver.punctuate(2);
    driver.punctuate(3);
    assertEquals(6, processor.processed.size());
    String[] expected = { "2:10", "20:110", "200:1110", "2000:11110", "-1:2", "-1:3" };
    for (int i = 0; i < expected.length; i++) {
        assertEquals(expected[i], processor.processed.get(i));
    }
}