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Merge branch 'master' into JAVA-1782-main

This commit is contained in:
Krzysiek 2020-06-08 00:11:03 +02:00
parent a1742fc856 024874d9c8
commit 1ccbc4027d
7 changed files with 233 additions and 2 deletions
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40
core-java-modules/core-java-lang-syntax/src/test/java/com/baeldung/varargs/HeapPollutionUnitTest.java Normal file
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@ -0,0 +1,40 @@
package com.baeldung.varargs;
import org.junit.Test;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import static org.junit.Assert.assertEquals;
public class HeapPollutionUnitTest {
@Test(expected = ClassCastException.class)
public void givenGenericVararg_whenUsedUnsafe_shouldThrowClassCastException() {
String one = firstOfFirst(Arrays.asList("one", "two"), Collections.emptyList());
assertEquals("one", one);
}
@Test(expected = ClassCastException.class)
public void givenGenericVararg_whenRefEscapes_mayCauseSubtleBugs() {
String[] args = returnAsIs("One", "Two");
}
private static String firstOfFirst(List<String>... strings) {
List<Integer> ints = Collections.singletonList(42);
Object[] objects = strings;
objects[0] = ints;
return strings[0].get(0);
}
private static <T> T[] toArray(T... arguments) {
return arguments;
}
private static <T> T[] returnAsIs(T a, T b) {
return toArray(a, b);
}
}

4
core-java-modules/core-java-reflection/src/test/java/com/baeldung/reflection/java/reflection/ReflectionUnitTest.java
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@ -200,7 +200,7 @@ public class ReflectionUnitTest {
@Test
public void givenClassField_whenSetsAndGetsValue_thenCorrect() throws Exception {
final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
final Bird bird = (Bird) birdClass.newInstance();
final Bird bird = (Bird) birdClass.getConstructor().newInstance();
final Field field = birdClass.getDeclaredField("walks");
field.setAccessible(true);
@ -266,7 +266,7 @@ public class ReflectionUnitTest {
@Test
public void givenMethod_whenInvokes_thenCorrect() throws Exception {
final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
final Bird bird = (Bird) birdClass.newInstance();
final Bird bird = (Bird) birdClass.getConstructor().newInstance();
final Method setWalksMethod = birdClass.getDeclaredMethod("setWalks", boolean.class);
final Method walksMethod = birdClass.getDeclaredMethod("walks");
final boolean walks = (boolean) walksMethod.invoke(bird);

11
core-java-modules/core-java-string-conversions/src/test/java/com/baeldung/stringtoint/StringToIntOrIntegerUnitTest.java
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@ -26,6 +26,17 @@ public class StringToIntOrIntegerUnitTest {
assertThat(result).isEqualTo(new Integer(42));
}
@Test
public void givenString_whenCallingValueOf_shouldCacheSomeValues() {
for (int i = -128; i <= 127; i++) {
String value = i + "";
Integer first = Integer.valueOf(value);
Integer second = Integer.valueOf(value);
assertThat(first).isSameAs(second);
}
}
@Test
public void givenString_whenCallingIntegerConstructor_shouldConvertToInt() {
String givenString = "42";

7
libraries-data-2/pom.xml
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@ -157,6 +157,13 @@
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>${byte-buddy.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>${kafka.version}</version>
<classifier>test</classifier>
<scope>test</scope>
</dependency>
</dependencies>

17
libraries-data-2/src/main/java/com/baeldung/kafka/producer/EvenOddPartitioner.java Normal file
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@ -0,0 +1,17 @@
package com.baeldung.kafka.producer;
import org.apache.kafka.clients.producer.internals.DefaultPartitioner;
import org.apache.kafka.common.Cluster;
public class EvenOddPartitioner extends DefaultPartitioner {
@Override
public int partition(String topic, Object key, byte[] keyBytes, Object value, byte[] valueBytes, Cluster cluster) {
if (((String) key).length() % 2 == 0) {
return 0;
}
return 1;
}
}

40
libraries-data-2/src/main/java/com/baeldung/kafka/producer/KafkaProducer.java Normal file
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@ -0,0 +1,40 @@
package com.baeldung.kafka.producer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import java.util.concurrent.Future;
public class KafkaProducer {
private final Producer<String, String> producer;
public KafkaProducer(Producer<String, String> producer) {
this.producer = producer;
}
public Future<RecordMetadata> send(String key, String value) {
ProducerRecord record = new ProducerRecord("topic_sports_news",
key, value);
return producer.send(record);
}
public void flush() {
producer.flush();
}
public void beginTransaction() {
producer.beginTransaction();
}
public void initTransaction() {
producer.initTransactions();
}
public void commitTransaction() {
producer.commitTransaction();
}
}

116
libraries-data-2/src/test/java/com/baeldung/kafka/producer/KafkaProducerUnitTest.java Normal file
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@ -0,0 +1,116 @@
package com.baeldung.kafka.producer;
import com.baeldung.kafka.producer.EvenOddPartitioner;
import com.baeldung.kafka.producer.KafkaProducer;
import org.apache.kafka.clients.producer.MockProducer;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.Cluster;
import org.apache.kafka.common.Node;
import org.apache.kafka.common.PartitionInfo;
import org.apache.kafka.common.serialization.StringSerializer;
import org.junit.jupiter.api.Test;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import static java.util.Collections.emptySet;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
class KafkaProducerUnitTest {
private final String TOPIC_NAME = "topic_sports_news";
private KafkaProducer kafkaProducer;
private MockProducer<String, String> mockProducer;
private void buildMockProducer(boolean autoComplete) {
this.mockProducer = new MockProducer<>(autoComplete, new StringSerializer(), new StringSerializer());
}
@Test
void givenKeyValue_whenSend_thenVerifyHistory() throws ExecutionException, InterruptedException {
buildMockProducer(true);
//when
kafkaProducer = new KafkaProducer(mockProducer);
Future<RecordMetadata> recordMetadataFuture = kafkaProducer.send("data", "{\"site\" : \"baeldung\"}");
//then
assertTrue(mockProducer.history().size() == 1);
assertTrue(mockProducer.history().get(0).key().equalsIgnoreCase("data"));
assertTrue(recordMetadataFuture.get().partition() == 0);
}
@Test
void givenKeyValue_whenSend_thenSendOnlyAfterFlush() {
buildMockProducer(false);
//when
kafkaProducer = new KafkaProducer(mockProducer);
Future<RecordMetadata> record = kafkaProducer.send("data", "{\"site\" : \"baeldung\"}");
assertFalse(record.isDone());
//then
kafkaProducer.flush();
assertTrue(record.isDone());
}
@Test
void givenKeyValue_whenSend_thenReturnException() {
buildMockProducer(false);
//when
kafkaProducer = new KafkaProducer(mockProducer);
Future<RecordMetadata> record = kafkaProducer.send("site", "{\"site\" : \"baeldung\"}");
RuntimeException e = new RuntimeException();
mockProducer.errorNext(e);
//then
try {
record.get();
} catch (ExecutionException | InterruptedException ex) {
assertEquals(e, ex.getCause());
}
assertTrue(record.isDone());
}
@Test
void givenKeyValue_whenSendWithTxn_thenSendOnlyOnTxnCommit() {
buildMockProducer(true);
//when
kafkaProducer = new KafkaProducer(mockProducer);
kafkaProducer.initTransaction();
kafkaProducer.beginTransaction();
Future<RecordMetadata> record = kafkaProducer.send("data", "{\"site\" : \"baeldung\"}");
//then
assertTrue(mockProducer.history().isEmpty());
kafkaProducer.commitTransaction();
assertTrue(mockProducer.history().size() == 1);
}
@Test
void givenKeyValue_whenSendWithPartitioning_thenVerifyPartitionNumber() throws ExecutionException, InterruptedException {
PartitionInfo partitionInfo0 = new PartitionInfo(TOPIC_NAME, 0, null, null, null);
PartitionInfo partitionInfo1 = new PartitionInfo(TOPIC_NAME, 1, null, null, null);
List<PartitionInfo> list = new ArrayList<>();
list.add(partitionInfo0);
list.add(partitionInfo1);
Cluster cluster = new Cluster("kafkab", new ArrayList<Node>(), list, emptySet(), emptySet());
this.mockProducer = new MockProducer<>(cluster, true, new EvenOddPartitioner(), new StringSerializer(), new StringSerializer());
//when
kafkaProducer = new KafkaProducer(mockProducer);
Future<RecordMetadata> recordMetadataFuture = kafkaProducer.send("partition", "{\"site\" : \"baeldung\"}");
//then
assertTrue(recordMetadataFuture.get().partition() == 1);
}
}