Merge pull request #16310 from sk1418/improvement-init-Long-list

[improvement-init-Long-list] add long list init
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Liam Williams 2024-04-08 23:56:18 +01:00 committed by GitHub
commit e6c33f07c4
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2 changed files with 91 additions and 59 deletions

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package com.baeldung.java.listInitialization;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import lombok.extern.java.Log;
import org.junit.Assert;
import org.junit.Test;
@Log
public class ListInitializationUnitTest {
@Test
public void givenAnonymousInnerClass_thenInitialiseList() {
List<String> cities = new ArrayList() {
{
add("New York");
add("Rio");
add("Tokyo");
}
};
Assert.assertTrue(cities.contains("New York"));
}
@Test
public void givenArraysAsList_thenInitialiseList() {
List<String> list = Arrays.asList("foo", "bar");
Assert.assertTrue(list.contains("foo"));
}
@Test(expected = UnsupportedOperationException.class)
public void givenArraysAsList_whenAdd_thenUnsupportedException() {
List<String> list = Arrays.asList("foo", "bar");
list.add("baz");
}
@Test
public void givenArraysAsList_whenCreated_thenShareReference() {
String[] array = { "foo", "bar" };
List<String> list = Arrays.asList(array);
array[0] = "baz";
Assert.assertEquals("baz", list.get(0));
}
@Test
public void givenStream_thenInitializeList() {
List<String> list = Stream.of("foo", "bar")
.collect(Collectors.toList());
Assert.assertTrue(list.contains("foo"));
}
}

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package com.baeldung.java.listinitialization;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.junit.Test;
import lombok.extern.java.Log;
@Log
public class ListInitializationUnitTest {
@Test
public void givenAnonymousInnerClass_thenInitialiseList() {
List<String> cities = new ArrayList() {
{
add("New York");
add("Rio");
add("Tokyo");
}
};
assertTrue(cities.contains("New York"));
}
@Test
public void givenArraysAsList_thenInitialiseList() {
List<String> list = Arrays.asList("foo", "bar");
assertTrue(list.contains("foo"));
}
@Test(expected = UnsupportedOperationException.class)
public void givenArraysAsList_whenAdd_thenUnsupportedException() {
List<String> list = Arrays.asList("foo", "bar");
list.add("baz");
}
@Test
public void givenArraysAsList_whenUsingArrayListConstructor_thenWeCanAddOrRemove() {
List<String> list = new ArrayList<>(Arrays.asList("foo", "bar"));
list.add("baz");
assertEquals(List.of("foo", "bar","baz"), list);
list.remove("baz");
assertEquals(List.of("foo", "bar"), list);
}
@Test
public void givenArraysAsList_whenCreated_thenShareReference() {
String[] array = { "foo", "bar" };
List<String> list = Arrays.asList(array);
array[0] = "baz";
assertEquals("baz", list.get(0));
}
@Test
public void givenIntNumbers_whenRequiredLong_thenCastAutomatically() {
int intNum = 42;
long longNum = intNum;
assertEquals(42L, longNum);
}
@Test
public void givenArrayAsList_whenRequiredLongList_thenGetExpectedResult() {
List<Long> listOfLongFixedSize = Arrays.asList(1L, 2L, 3L);
List<Long> listOfLong = new ArrayList<>(Arrays.asList(1L, 2L, 3L));
List<Long> expected = List.of(1L, 2L, 3L);
assertEquals(expected, listOfLongFixedSize);
assertEquals(expected, listOfLong);
}
@Test
public void givenStream_thenInitializeList() {
List<String> list = Stream.of("foo", "bar")
.collect(Collectors.toList());
assertTrue(list.contains("foo"));
}
}