pull from master

This commit is contained in:
@hangga
2023-11-12 18:23:58 +07:00
196 changed files with 2821 additions and 2009 deletions
@@ -0,0 +1,129 @@
package com.baeldung.algorithms.connect4;
import java.util.ArrayList;
import java.util.List;
public class GameBoard {
private final List<List<Piece>> columns;
private final int rows;
public GameBoard(int columns, int rows) {
this.rows = rows;
this.columns = new ArrayList<>();
for (int i = 0; i < columns; ++i) {
this.columns.add(new ArrayList<>());
}
}
public int getRows() {
return rows;
}
public int getColumns() {
return columns.size();
}
public Piece getCell(int x, int y) {
assert(x >= 0 && x < getColumns());
assert(y >= 0 && y < getRows());
List<Piece> column = columns.get(x);
if (column.size() > y) {
return column.get(y);
} else {
return null;
}
}
public boolean move(int x, Piece player) {
assert(x >= 0 && x < getColumns());
List<Piece> column = columns.get(x);
if (column.size() >= this.rows) {
throw new IllegalArgumentException("That column is full");
}
column.add(player);
return checkWin(x, column.size() - 1, player);
}
private boolean checkWin(int x, int y, Piece player) {
// Vertical line
if (checkLine(x, y, 0, -1, player)) {
return true;
}
for (int offset = 0; offset < 4; ++offset) {
// Horizontal line
if (checkLine(x - 3 + offset, y, 1, 0, player)) {
return true;
}
// Leading diagonal
if (checkLine(x - 3 + offset, y + 3 - offset, 1, -1, player)) {
return true;
}
// Trailing diagonal
if (checkLine(x - 3 + offset, y - 3 + offset, 1, 1, player)) {
return true;
}
}
return false;
}
private boolean checkLine(int x1, int y1, int xDiff, int yDiff, Piece player) {
for (int i = 0; i < 4; ++i) {
int x = x1 + (xDiff * i);
int y = y1 + (yDiff * i);
if (x < 0 || x > columns.size() - 1) {
return false;
}
if (y < 0 || y > rows - 1) {
return false;
}
if (player != getCell(x, y)) {
return false;
}
}
return true;
}
@Override
public String toString() {
StringBuilder result = new StringBuilder();
for (int y = getRows() - 1; y >= 0; --y) {
for (int x = 0; x < getColumns(); ++x) {
Piece piece = getCell(x, y);
result.append("|");
if (piece == null) {
result.append(" ");
} else if (piece == Piece.PLAYER_1) {
result.append("X");
} else if (piece == Piece.PLAYER_2) {
result.append("O");
}
}
result.append("|\n");
for (int i = 0; i < getColumns(); ++i) {
result.append("+-");
}
result.append("+\n");
}
return result.toString();
}
}
@@ -0,0 +1,40 @@
package com.baeldung.algorithms.connect4;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
public class GameUnitTest {
@Test
public void blankGame() {
GameBoard gameBoard = new GameBoard(8, 6);
System.out.println(gameBoard);
}
@Test
public void playedGame() {
GameBoard gameBoard = new GameBoard(8, 6);
assertFalse(gameBoard.move(3, Piece.PLAYER_1));
assertFalse(gameBoard.move(2, Piece.PLAYER_2));
assertFalse(gameBoard.move(4, Piece.PLAYER_1));
assertFalse(gameBoard.move(3, Piece.PLAYER_2));
assertFalse(gameBoard.move(5, Piece.PLAYER_1));
assertFalse(gameBoard.move(6, Piece.PLAYER_2));
assertFalse(gameBoard.move(5, Piece.PLAYER_1));
assertFalse(gameBoard.move(4, Piece.PLAYER_2));
assertFalse(gameBoard.move(5, Piece.PLAYER_1));
assertFalse(gameBoard.move(5, Piece.PLAYER_2));
assertFalse(gameBoard.move(6, Piece.PLAYER_1));
assertTrue(gameBoard.move(4, Piece.PLAYER_2));
System.out.println(gameBoard);
}
}
@@ -0,0 +1,6 @@
package com.baeldung.algorithms.connect4;
public enum Piece {
PLAYER_1,
PLAYER_2
}
@@ -0,0 +1,2 @@
## Relevant Articles
- [Implement Connect 4 Game with Java](https://www.baeldung.com/java-connect-4-game)
@@ -0,0 +1,113 @@
package com.baeldung.rounddate;
import java.time.DayOfWeek;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAdjusters;
import java.util.Calendar;
import java.util.Date;
import java.time.LocalDateTime;
import java.time.ZonedDateTime;
public class RoundDate {
public static Date getDate(int year, int month, int day, int hour, int minute) {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.MONTH, month);
calendar.set(Calendar.DAY_OF_MONTH, day);
calendar.set(Calendar.HOUR_OF_DAY, hour);
calendar.set(Calendar.MINUTE, minute);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
return calendar.getTime();
}
public static Date roundToDay(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
return calendar.getTime();
}
public static Date roundToNearestUnit(Date date, int unit) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
switch (unit) {
case Calendar.HOUR:
int minute = calendar.get(Calendar.MINUTE);
if (minute >= 0 && minute < 15) {
calendar.set(Calendar.MINUTE, 0);
} else if (minute >= 15 && minute < 45) {
calendar.set(Calendar.MINUTE, 30);
} else {
calendar.set(Calendar.MINUTE, 0);
calendar.add(Calendar.HOUR_OF_DAY, 1);
}
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
break;
case Calendar.DAY_OF_MONTH:
int hour = calendar.get(Calendar.HOUR_OF_DAY);
if (hour >= 12) {
calendar.add(Calendar.DAY_OF_MONTH, 1);
}
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
break;
case Calendar.MONTH:
int day = calendar.get(Calendar.DAY_OF_MONTH);
if (day >= 15) {
calendar.add(Calendar.MONTH, 1);
}
calendar.set(Calendar.DAY_OF_MONTH, 1);
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
break;
}
return calendar.getTime();
}
public static LocalDateTime roundToStartOfMonthUsingLocalDateTime(LocalDateTime dateTime) {
return dateTime.withDayOfMonth(1).withHour(0).withMinute(0).withSecond(0).withNano(0);
}
public static LocalDateTime roundToEndOfWeekUsingLocalDateTime(LocalDateTime dateTime) {
return dateTime.with(TemporalAdjusters.next(DayOfWeek.SATURDAY))
.withHour(23)
.withMinute(59)
.withSecond(59)
.withNano(999);
}
public static ZonedDateTime roundToStartOfMonthUsingZonedDateTime(ZonedDateTime dateTime) {
return dateTime.withDayOfMonth(1)
.withHour(0)
.withMinute(0)
.withSecond(0)
.with(ChronoField.MILLI_OF_SECOND, 0)
.with(ChronoField.MICRO_OF_SECOND, 0)
.with(ChronoField.NANO_OF_SECOND, 0);
}
public static ZonedDateTime roundToEndOfWeekUsingZonedDateTime(ZonedDateTime dateTime) {
return dateTime.with(TemporalAdjusters.next(DayOfWeek.SATURDAY))
.withHour(23)
.withMinute(59)
.withSecond(59)
.with(ChronoField.MILLI_OF_SECOND, 999)
.with(ChronoField.MICRO_OF_SECOND, 999)
.with(ChronoField.NANO_OF_SECOND, 999);
}
}
@@ -0,0 +1,63 @@
package com.baeldung.rounddate;
import org.junit.Test;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.Calendar;
import java.util.Date;
import static org.junit.Assert.assertEquals;
public class DateRoundingUnitTest {
@Test
public void givenDate_whenRoundToDay_thenBeginningOfDay() {
Date date = RoundDate.getDate(2023, Calendar.JANUARY, 27, 14, 30);
Date result = RoundDate.roundToDay(date);
assertEquals(RoundDate.getDate(2023, Calendar.JANUARY, 27, 0, 0), result);
}
@Test
public void givenDate_whenRoundToNearestUnit_thenNearestUnit() {
Date date = RoundDate.getDate(2023, Calendar.JANUARY, 27, 14, 12);
Date result = RoundDate.roundToNearestUnit(date, Calendar.DAY_OF_MONTH);
Date expected = RoundDate.getDate(2023, Calendar.JANUARY, 28, 0, 0);
assertEquals(expected, result);
}
@Test
public void givenLocalDateTime_whenRoundToStartOfMonth_thenStartOfMonth() {
LocalDateTime dateTime = LocalDateTime.of(2023, 1, 27, 14, 12);
LocalDateTime result = RoundDate.roundToStartOfMonthUsingLocalDateTime(dateTime);
LocalDateTime expected = LocalDateTime.of(2023, 1, 1, 0, 0, 0);
assertEquals(expected, result);
}
@Test
public void givenZonedDateTime_whenRoundToStartOfMonth_thenStartOfMonth() {
ZonedDateTime dateTime = ZonedDateTime.of(2023, 1, 27, 14, 12, 0, 0, ZoneId.systemDefault());
ZonedDateTime result = RoundDate.roundToStartOfMonthUsingZonedDateTime(dateTime);
ZonedDateTime expected = ZonedDateTime.of(2023, 1, 1, 0, 0, 0, 0, ZoneId.systemDefault());
assertEquals(expected, result);
}
@Test
public void givenLocalDateTime_whenRoundToEndOfWeek_thenEndOfWeek() {
LocalDateTime dateTime = LocalDateTime.of(2023, 1, 27, 14, 12);
LocalDateTime result = RoundDate.roundToEndOfWeekUsingLocalDateTime(dateTime);
LocalDateTime expected = LocalDateTime.of(2023, 1, 28, 23, 59, 59, 999);
assertEquals(expected, result);
}
@Test
public void givenZonedDateTime_whenRoundToEndOfWeek_thenEndOfWeek() {
ZonedDateTime dateTime = ZonedDateTime.of(2023, 1, 27, 14, 12, 0, 0, ZoneId.systemDefault());
ZonedDateTime result = RoundDate.roundToEndOfWeekUsingZonedDateTime(dateTime);
ZonedDateTime expected = ZonedDateTime.of(2023, 1, 28, 23, 59, 59, 999, ZoneId.systemDefault());
assertEquals(expected, result);
}
}
@@ -0,0 +1,48 @@
package com.baeldung.spliterator;
import java.util.List;
import java.util.Spliterator;
import java.util.function.Consumer;
public class CustomSpliterator implements Spliterator<Integer> {
private final List<Integer> elements;
private int currentIndex;
public CustomSpliterator(List<Integer> elements) {
this.elements = elements;
this.currentIndex = 0;
}
@Override
public boolean tryAdvance(Consumer<? super Integer> action) {
if (currentIndex < elements.size()) {
action.accept(elements.get(currentIndex));
currentIndex++;
return true;
}
return false;
}
@Override
public Spliterator<Integer> trySplit() {
int currentSize = elements.size() - currentIndex;
if (currentSize < 2) {
return null;
}
int splitIndex = currentIndex + currentSize / 2;
CustomSpliterator newSpliterator = new CustomSpliterator(elements.subList(currentIndex, splitIndex));
currentIndex = splitIndex;
return newSpliterator;
}
@Override
public long estimateSize() {
return elements.size() - currentIndex;
}
@Override
public int characteristics() {
return ORDERED | SIZED | SUBSIZED | NONNULL;
}
}
@@ -1,12 +0,0 @@
package com.baeldung.spliterator;
import java.util.stream.Stream;
public class Executor {
public static int countAutors(Stream<Author> stream) {
RelatedAuthorCounter wordCounter = stream.reduce(new RelatedAuthorCounter(0, true),
RelatedAuthorCounter::accumulate, RelatedAuthorCounter::combine);
return wordCounter.getCounter();
}
}
@@ -1,27 +0,0 @@
package com.baeldung.spliterator;
public class RelatedAuthorCounter {
private final int counter;
private final boolean isRelated;
public RelatedAuthorCounter(int counter, boolean isRelated) {
this.counter = counter;
this.isRelated = isRelated;
}
public RelatedAuthorCounter accumulate(Author author) {
if (author.getRelatedArticleId() == 0) {
return isRelated ? this : new RelatedAuthorCounter(counter, true);
} else {
return isRelated ? new RelatedAuthorCounter(counter + 1, false) : this;
}
}
public RelatedAuthorCounter combine(RelatedAuthorCounter RelatedAuthorCounter) {
return new RelatedAuthorCounter(counter + RelatedAuthorCounter.counter, RelatedAuthorCounter.isRelated);
}
public int getCounter() {
return counter;
}
}
@@ -1,49 +0,0 @@
package com.baeldung.spliterator;
import java.util.List;
import java.util.Spliterator;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Consumer;
public class RelatedAuthorSpliterator implements Spliterator<Author> {
private final List<Author> list;
AtomicInteger current = new AtomicInteger();
public RelatedAuthorSpliterator(List<Author> list) {
this.list = list;
}
@Override
public boolean tryAdvance(Consumer<? super Author> action) {
action.accept(list.get(current.getAndIncrement()));
return current.get() < list.size();
}
@Override
public Spliterator<Author> trySplit() {
int currentSize = list.size() - current.get();
if (currentSize < 10) {
return null;
}
for (int splitPos = currentSize / 2 + current.intValue(); splitPos < list.size(); splitPos++) {
if (list.get(splitPos).getRelatedArticleId() == 0) {
Spliterator<Author> spliterator = new RelatedAuthorSpliterator(list.subList(current.get(), splitPos));
current.set(splitPos);
return spliterator;
}
}
return null;
}
@Override
public long estimateSize() {
return list.size() - current.get();
}
@Override
public int characteristics() {
return CONCURRENT;
}
}
@@ -6,10 +6,10 @@ import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Spliterator;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import org.junit.Before;
import org.junit.Test;
@@ -18,22 +18,50 @@ import lombok.extern.slf4j.Slf4j;
@Slf4j
public class ExecutorUnitTest {
Article article;
Stream<Author> stream;
Spliterator<Author> spliterator;
@Before
public void init() {
article = new Article(Arrays.asList(new Author("Ahmad", 0), new Author("Eugen", 0), new Author("Alice", 1), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0),
new Author("Alice", 1), new Author("Mike", 0), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1),
new Author("Mike", 0), new Author("Michał", 0), new Author("Loredana", 1)), 0);
spliterator = new RelatedAuthorSpliterator(article.getListOfAuthors());
}
@Test
public void givenAstreamOfAuthors_whenProcessedInParallelWithCustomSpliterator_coubtProducessRightOutput() {
Stream<Author> stream2 = StreamSupport.stream(spliterator, true);
assertThat(Executor.countAutors(stream2.parallel())).isEqualTo(9);
public void givenAStreamOfIntegers_whenProcessedSequentialCustomSpliterator_countProducesRightOutput() {
List<Integer> numbers = new ArrayList<>();
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
numbers.add(5);
CustomSpliterator customSpliterator = new CustomSpliterator(numbers);
AtomicInteger sum = new AtomicInteger();
customSpliterator.forEachRemaining(sum::addAndGet);
assertThat(sum.get()).isEqualTo(15);
}
@Test
public void givenAStreamOfIntegers_whenProcessedInParallelWithCustomSpliterator_countProducesRightOutput() {
List<Integer> numbers = new ArrayList<>();
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
numbers.add(5);
CustomSpliterator customSpliterator = new CustomSpliterator(numbers);
// Create a ForkJoinPool for parallel processing
ForkJoinPool forkJoinPool = ForkJoinPool.commonPool();
AtomicInteger sum = new AtomicInteger(0);
// Process elements in parallel using parallelStream
forkJoinPool.submit(() -> customSpliterator.forEachRemaining(sum::addAndGet)).join();
assertThat(sum.get()).isEqualTo(15);
}
@Test
@@ -43,9 +71,7 @@ public class ExecutorUnitTest {
.collect(Collectors.toList());
Spliterator<Article> spliterator = articles.spliterator();
while (spliterator.tryAdvance(article -> article.setName(article.getName()
.concat("- published by Baeldung"))))
;
while(spliterator.tryAdvance(article -> article.setName(article.getName().concat("- published by Baeldung"))));
articles.forEach(article -> assertThat(article.getName()).isEqualTo("Java- published by Baeldung"));
}
@@ -0,0 +1,87 @@
package com.baeldung.vectors;
import static org.junit.Assert.assertEquals;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Vector;
import org.junit.Test;
public class VectorOperationsUnitTest {
private static Vector<String> getVector() {
Vector<String> vector = new Vector<String>();
vector.add("Today");
vector.add("is");
vector.add("a");
vector.add("great");
vector.add("day!");
return vector;
}
@Test
public void givenAVector_whenAddElementsUsingAddMethod_thenElementsGetAddedAtEnd() {
Vector<String> vector = getVector();
vector.add("Hello");
assertEquals(6, vector.size());
}
@Test
public void givenAVector_whenUpdateElementAtIndex_thenElementAtIndexGetsUpdated() {
Vector<String> vector = getVector();
assertEquals(5, vector.size());
assertEquals("great", vector.get(3));
vector.set(3, "good");
assertEquals("good", vector.get(3));
}
@Test
public void givenAVector_whenRemoveAnElement_thenElementGetsRemovedFromTheVector() {
Vector<String> vector = getVector();
assertEquals(5, vector.size());
// remove a specific element
vector.remove("a");
assertEquals(4, vector.size());
// remove at specific index
vector.remove(2);
assertEquals("day!", vector.get(2));
assertEquals(3, vector.size());
assertEquals(false, vector.remove("SomethingThatDoesn'tExist"));
}
@Test(expected = ArrayIndexOutOfBoundsException.class)
public void givenAVector_whenIndexIsBeyondRange_thenRemoveMethodThrowsArrayIndexOutOfBoundsException() {
Vector<String> vector = getVector();
assertEquals(5, vector.size());
vector.remove(10);
}
@Test
public void givenAVector_whenGetElementWithinARange_thenGetMethodGetsAnElementFromTheVector() {
Vector<String> vector = getVector();
String fourthElement = vector.get(3);
assertEquals("great", fourthElement);
}
@Test(expected = ArrayIndexOutOfBoundsException.class)
public void givenAVector_whenGetElementBeyondARange_thenGetMethodThrowsArrayIndexOutOfBoundsException() {
Vector<String> vector = getVector();
assertEquals(5, vector.size());
vector.get(10);
}
@Test
public void givenAVector_whenAddElementFromACollection_thenAllElementsGetAdeddToTheVector() {
Vector<String> vector = getVector();
assertEquals(5, vector.size());
ArrayList<String> words = new ArrayList<>(Arrays.asList("Baeldung", "is", "cool!"));
vector.addAll(words);
assertEquals(8, vector.size());
assertEquals("cool!", vector.get(7));
}
}
@@ -79,5 +79,18 @@
<version>1.5</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<argLine>
--add-opens java.base/java.util=ALL-UNNAMED
</argLine>
</configuration>
</plugin>
</plugins>
</build>
</project>
@@ -0,0 +1,85 @@
package com.baeldung.map.linkedhashmapfirstandlastentry;
import org.junit.jupiter.api.Test;
import java.lang.reflect.Field;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map.Entry;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
public class GetFirstAndLastEntryFromLinkedHashMapUnitTest {
private static final LinkedHashMap<String, String> THE_MAP = new LinkedHashMap<>();
static {
THE_MAP.put("key one", "a1 b1 c1");
THE_MAP.put("key two", "a2 b2 c2");
THE_MAP.put("key three", "a3 b3 c3");
THE_MAP.put("key four", "a4 b4 c4");
}
@Test
void whenIteratingEntrySet_thenGetExpectedResult() {
Entry<String, String> firstEntry = THE_MAP.entrySet().iterator().next();
assertEquals("key one", firstEntry.getKey());
assertEquals("a1 b1 c1", firstEntry.getValue());
Entry<String, String> lastEntry = null;
Iterator<Entry<String, String>> it = THE_MAP.entrySet().iterator();
while (it.hasNext()) {
lastEntry = it.next();
}
assertNotNull(lastEntry);
assertEquals("key four", lastEntry.getKey());
assertEquals("a4 b4 c4", lastEntry.getValue());
}
@Test
void whenConvertingEntriesToArray_thenGetExpectedResult() {
Entry<String, String>[] theArray = new Entry[THE_MAP.size()];
THE_MAP.entrySet().toArray(theArray);
Entry<String, String> firstEntry = theArray[0];
assertEquals("key one", firstEntry.getKey());
assertEquals("a1 b1 c1", firstEntry.getValue());
Entry<String, String> lastEntry = theArray[THE_MAP.size() - 1];
assertEquals("key four", lastEntry.getKey());
assertEquals("a4 b4 c4", lastEntry.getValue());
}
@Test
void whenUsingStreamAPI_thenGetExpectedResult() {
Entry<String, String> firstEntry = THE_MAP.entrySet().stream().findFirst().get();
assertEquals("key one", firstEntry.getKey());
assertEquals("a1 b1 c1", firstEntry.getValue());
Entry<String, String> lastEntry = THE_MAP.entrySet().stream().skip(THE_MAP.size() - 1).findFirst().get();
assertNotNull(lastEntry);
assertEquals("key four", lastEntry.getKey());
assertEquals("a4 b4 c4", lastEntry.getValue());
}
@Test
void whenUsingReflection_thenGetExpectedResult() throws NoSuchFieldException, IllegalAccessException {
Field head = THE_MAP.getClass().getDeclaredField("head");
head.setAccessible(true);
Entry<String, String> firstEntry = (Entry<String, String>) head.get(THE_MAP);
assertEquals("key one", firstEntry.getKey());
assertEquals("a1 b1 c1", firstEntry.getValue());
Field tail = THE_MAP.getClass().getDeclaredField("tail");
tail.setAccessible(true);
Entry<String, String> lastEntry = (Entry<String, String>) tail.get(THE_MAP);
assertEquals("key four", lastEntry.getKey());
assertEquals("a4 b4 c4", lastEntry.getValue());
}
}
@@ -11,4 +11,5 @@ This module contains articles about basic Java concurrency.
- [CompletableFuture and ThreadPool in Java](https://www.baeldung.com/java-completablefuture-threadpool)
- [CompletableFuture allOf().join() vs. CompletableFuture.join()](https://www.baeldung.com/java-completablefuture-allof-join)
- [Retry Logic with CompletableFuture](https://www.baeldung.com/java-completablefuture-retry-logic)
- [Convert From List of CompletableFuture to CompletableFuture List](https://www.baeldung.com/java-completablefuture-list-convert)
- [[<-- Prev]](../core-java-concurrency-basic-2)
@@ -0,0 +1,23 @@
package com.baeldung.generictype;
/**
* @param <T> The type of the first value in the {@code Pair<T,S>}.
* @param <S> The type of the second value in the {@code Pair<T,S>}.
*/
public class Pair<T, S> {
public T first;
public S second;
/**
* Constructs a new Pair object with the specified values.
*
* @param a The first value.
* @param b The second value.
*/
public Pair(T a, S b) {
first = a;
second = b;
}
}
@@ -5,5 +5,6 @@ This module contains articles about core Java input and output (IO)
### Relevant Articles:
- [Get File Extension From MIME Type in Java](https://www.baeldung.com/java-mime-type-file-extension)
- [How to Remove Line Breaks From a File in Java](https://www.baeldung.com/java-file-remove-line-breaks)
- [Difference Between ZipFile and ZipInputStream in Java](https://www.baeldung.com/java-zipfile-vs-zipinputstream)
- [[<-- Prev]](/core-java-modules/core-java-io-4)
@@ -8,3 +8,4 @@ This module contains articles about core Java input/output(IO) APIs.
- [Check if a File Is Empty in Java](https://www.baeldung.com/java-check-file-empty)
- [Converting Relative to Absolute Paths in Java](https://www.baeldung.com/java-from-relative-to-absolute-paths)
- [Detect EOF in Java](https://www.baeldung.com/java-file-detect-end-of-file)
- [PrintWriter vs. FileWriter in Java](https://www.baeldung.com/java-printwriter-filewriter-difference)
@@ -56,7 +56,7 @@
<source.version>11</source.version>
<target.version>11</target.version>
<json.version>20200518</json.version>
<opencsv.version>4.1</opencsv.version>
<opencsv.version>5.8</opencsv.version>
</properties>
</project>
@@ -0,0 +1,72 @@
package com.baeldung.jndi;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.jndi.JndiTemplate;
import org.springframework.mock.jndi.SimpleNamingContextBuilder;
import javax.naming.*;
import javax.sql.DataSource;
import java.util.Enumeration;
import static org.junit.jupiter.api.Assertions.*;
class JndiNamingUnitTest {
private static InitialContext context;
private static DriverManagerDataSource dataSource;
@BeforeAll
static void setUp() throws Exception {
SimpleNamingContextBuilder builder = new SimpleNamingContextBuilder();
dataSource = new DriverManagerDataSource("jdbc:h2:mem:mydb");
builder.activate();
JndiTemplate jndiTemplate = new JndiTemplate();
context = (InitialContext) jndiTemplate.getContext();
dataSource.setDriverClassName("org.h2.Driver");
context.bind("java:comp/env/jdbc/datasource", dataSource);
}
@Test
void givenACompositeName_whenAddingAnElement_thenNameIsAdded() throws Exception {
Name objectName = new CompositeName("java:comp/env/jdbc");
Enumeration<String> items = objectName.getAll();
while(items.hasMoreElements()) {
System.out.println(items.nextElement());
}
objectName.add("New Name");
assertEquals("env", objectName.get(1));
assertEquals("New Name", objectName.get(objectName.size() - 1));
}
@Test
void givenContext_whenLookupByName_thenReturnsValidObject() throws Exception {
DataSource ds = (DataSource) context.lookup("java:comp/env/jdbc/datasource");
assertNotNull(ds);
assertNotNull(ds.getConnection());
}
@Test
void givenSubContext_whenLookupByName_thenReturnsValidObject() throws Exception {
Context subContext = (Context) context.lookup("java:comp/env");
DataSource ds = (DataSource) subContext.lookup("jdbc/datasource");
assertNotNull(ds);
assertNotNull(ds.getConnection());
}
@AfterAll
static void tearDown() throws Exception {
context.close();
}
}
@@ -0,0 +1,122 @@
package com.baeldung.genericnumberscomparator;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;
import java.util.function.Function;
import org.junit.jupiter.api.Test;
class GenericNumbersComparatorUnitTest {
public int compareDouble(Number num1, Number num2) {
return Double.compare(num1.doubleValue(), num2.doubleValue());
}
@Test
void givenNumbers_whenUseCompareDouble_thenWillExecuteComparison() {
assertEquals(0, compareDouble(5, 5.0));
}
public int compareTo(Integer int1, Integer int2) {
return int1.compareTo(int2);
}
@Test
void givenNumbers_whenUseCompareTo_thenWillExecuteComparison() {
assertEquals(-1, compareTo(5, 7));
}
Map<Class<? extends Number>, BiFunction<Number, Number, Integer>> comparisonMap = new HashMap<>();
public int compareUsingMap(Number num1, Number num2) {
comparisonMap.put(Integer.class, (a, b) -> ((Integer) num1).compareTo((Integer) num2));
return comparisonMap.get(num1.getClass())
.apply(num1, num2);
}
@Test
void givenNumbers_whenUseCompareUsingMap_thenWillExecuteComparison() {
assertEquals(-1, compareUsingMap(5, 7));
}
public interface NumberComparator {
int compare(Number num1, Number num2);
}
@Test
void givenNumbers_whenUseProxy_thenWillExecuteComparison() {
NumberComparator proxy = (NumberComparator) Proxy.newProxyInstance(NumberComparator.class.getClassLoader(), new Class[] { NumberComparator.class },
(p, method, args) -> Double.compare(((Number) args[0]).doubleValue(), ((Number) args[1]).doubleValue()));
assertEquals(0, proxy.compare(5, 5.0));
}
public int compareUsingReflection(Number num1, Number num2) throws Exception {
Method method = num1.getClass()
.getMethod("compareTo", num1.getClass());
return (int) method.invoke(num1, num2);
}
@Test
void givenNumbers_whenUseCompareUsingReflection_thenWillExecuteComparison() throws Exception {
assertEquals(-1, compareUsingReflection(5, 7));
}
interface NumberComparatorFactory {
Comparator<Number> getComparator();
}
class IntegerComparatorFactory implements NumberComparatorFactory {
@Override
public Comparator<Number> getComparator() {
return (num1, num2) -> ((Integer) num1).compareTo((Integer) num2);
}
}
@Test
void givenNumbers_whenUseComparatorFactory_thenWillExecuteComparison() {
NumberComparatorFactory factory = new IntegerComparatorFactory();
Comparator<Number> comparator = factory.getComparator();
assertEquals(-1, comparator.compare(5, 7));
}
Function<Number, Double> toDouble = Number::doubleValue;
BiPredicate<Number, Number> isEqual = (num1, num2) -> toDouble.apply(num1)
.equals(toDouble.apply(num2));
@Test
void givenNumbers_whenUseIsEqual_thenWillExecuteComparison() {
assertEquals(true, isEqual.test(5, 5.0));
}
private Number someNumber = 5;
private Number anotherNumber = 5.0;
Optional<Number> optNum1 = Optional.ofNullable(someNumber);
Optional<Number> optNum2 = Optional.ofNullable(anotherNumber);
int comparisonResult = optNum1.flatMap(n1 -> optNum2.map(n2 -> Double.compare(n1.doubleValue(), n2.doubleValue())))
.orElse(0);
@Test
void givenNumbers_whenUseComparisonResult_thenWillExecuteComparison() {
assertEquals(0, comparisonResult);
}
private boolean someCondition = true;
Function<Number, ?> dynamicFunction = someCondition ? Number::doubleValue : Number::intValue;
Comparator<Number> dynamicComparator = (num1, num2) -> ((Comparable) dynamicFunction.apply(num1)).compareTo(dynamicFunction.apply(num2));
@Test
void givenNumbers_whenUseDynamicComparator_thenWillExecuteComparison() {
assertEquals(0, dynamicComparator.compare(5, 5.0));
}
}
@@ -0,0 +1,6 @@
package com.baeldung.optionalsasparameterrecords;
import java.util.Optional;
public record Product(String name, double price, Optional<String> description) {
}
@@ -0,0 +1,17 @@
package com.baeldung.optionalsasparameterrecords;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import java.util.Optional;
public class OptionalAsRecordParameterUnitTest {
@Test
public void givenRecordCreationWithOptional_thenCreateItProperly() {
var emptyDescriptionProduct = new Product("television", 1699.99, Optional.empty());
Assertions.assertEquals("television", emptyDescriptionProduct.name());
Assertions.assertEquals(1699.99, emptyDescriptionProduct.price());
Assertions.assertNull(emptyDescriptionProduct.description().orElse(null));
}
}
@@ -85,7 +85,7 @@ public class AlphanumericPerformanceBenchmark {
public boolean isAlphanumeric(final int codePoint) {
return (codePoint >= 65 && codePoint <= 90) ||
(codePoint >= 97 && codePoint <= 172) ||
(codePoint >= 97 && codePoint <= 122) ||
(codePoint >= 48 && codePoint <= 57);
}
}
@@ -0,0 +1,100 @@
package com.baeldung.streamtomapandmultimap;
import com.google.common.collect.LinkedHashMultimap;
import org.junit.Test;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static org.junit.Assert.assertEquals;
public class StreamToMapAndMultiMapUnitTest {
@Test
public void givenStringStream_whenConvertingToMapWithMerge_thenExpectedMapIsGenerated() {
Stream<String> stringStream = Stream.of("one", "two", "three", "two");
Map<String, String> mergedMap = stringStream.collect(
Collectors.toMap(s -> s, s -> s, (s1, s2) -> s1 + ", " + s2)
);
// Define the expected map
Map<String, String> expectedMap = Map.of(
"one", "one",
"two", "two, two",
"three", "three"
);
assertEquals(expectedMap, mergedMap);
}
@Test
public void givenStringStream_whenConvertingToMultimap_thenExpectedMultimapIsGenerated() {
Stream<String> stringStream = Stream.of("one", "two", "three", "two");
LinkedHashMultimap<Object, Object> multimap = LinkedHashMultimap.create();
stringStream.collect(Collectors.groupingBy(
s -> s,
Collectors.mapping(s -> s, Collectors.toList())
)).forEach((key, value) -> multimap.putAll(key, value));
LinkedHashMultimap<Object, Object> expectedMultimap = LinkedHashMultimap.create();
expectedMultimap.put("one", "one");
expectedMultimap.put("two", "two");
expectedMultimap.put("three", "three");
assertEquals(expectedMultimap, multimap);
}
@Test
public void givenStringStream_whenConvertingToMultimapWithStreamReduce_thenExpectedMultimapIsGenerated() {
Stream<String> stringStream = Stream.of("one", "two", "three", "two");
Map<String, List<String>> multimap = stringStream.reduce(
new HashMap<>(),
(map, element) -> {
map.computeIfAbsent(element, k -> new ArrayList<>()).add(element);
return map;
},
(map1, map2) -> {
map2.forEach((key, value) -> map1.merge(key, value, (list1, list2) -> {
list1.addAll(list2);
return list1;
}));
return map1;
}
);
Map<String, List<String>> expectedMultimap = new HashMap<>();
expectedMultimap.put("one", Collections.singletonList("one"));
expectedMultimap.put("two", Arrays.asList("two", "two"));
expectedMultimap.put("three", Collections.singletonList("three"));
assertEquals(expectedMultimap, multimap);
}
@Test
public void givenStringStream_whenConvertingToMapWithStreamReduce_thenExpectedMapIsGenerated() {
Stream<String> stringStream = Stream.of("one", "two", "three", "two");
Map<String, String> resultMap = stringStream.reduce(
new HashMap<>(),
(map, element) -> {
map.put(element, element);
return map;
},
(map1, map2) -> {
map1.putAll(map2);
return map1;
}
);
Map<String, String> expectedMap = new HashMap<>();
expectedMap.put("one", "one");
expectedMap.put("two", "two");
expectedMap.put("three", "three");
assertEquals(expectedMap, resultMap);
}
}
@@ -1,7 +1,11 @@
package com.baeldung.streams;
import org.junit.Before;
import org.junit.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import java.nio.file.Path;
import java.nio.file.Paths;
@@ -11,14 +15,12 @@ import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static org.junit.Assert.*;
class Java8StreamsUnitTest {
public class Java8StreamsUnitTest {
private static List<String> list;
private List<String> list;
@Before
public void init() {
@BeforeAll
public static void init() {
list = new ArrayList<>();
list.add("One");
list.add("OneAndOnly");
@@ -42,60 +44,73 @@ public class Java8StreamsUnitTest {
Stream<String> streamOf = Stream.of("a", "b", "c");
assertEquals(streamOf.count(), 3);
long count = list.stream().distinct().count();
long count = list.stream()
.distinct()
.count();
assertEquals(count, 9);
}
@Test
public void checkStreamCount_whenOperationFilter_thanCorrect() {
Stream<String> streamFilter = list.stream().filter(element -> element.isEmpty());
void checkStreamCount_whenOperationFilter_thanCorrect() {
Stream<String> streamFilter = list.stream()
.filter(element -> element.isEmpty());
assertEquals(streamFilter.count(), 2);
}
@Test
public void checkStreamCount_whenOperationMap_thanCorrect() {
void checkStreamCount_whenOperationMap_thanCorrect() {
List<String> uris = new ArrayList<>();
uris.add("C:\\My.txt");
Stream<Path> streamMap = uris.stream().map(uri -> Paths.get(uri));
Stream<Path> streamMap = uris.stream()
.map(uri -> Paths.get(uri));
assertEquals(streamMap.count(), 1);
List<Detail> details = new ArrayList<>();
details.add(new Detail());
details.add(new Detail());
Stream<String> streamFlatMap = details.stream().flatMap(detail -> detail.getParts().stream());
Stream<String> streamFlatMap = details.stream()
.flatMap(detail -> detail.getParts()
.stream());
assertEquals(streamFlatMap.count(), 4);
}
@Test
public void checkStreamCount_whenOperationMatch_thenCorrect() {
boolean isValid = list.stream().anyMatch(element -> element.contains("h"));
boolean isValidOne = list.stream().allMatch(element -> element.contains("h"));
boolean isValidTwo = list.stream().noneMatch(element -> element.contains("h"));
void checkStreamCount_whenOperationMatch_thenCorrect() {
boolean isValid = list.stream()
.anyMatch(element -> element.contains("h"));
boolean isValidOne = list.stream()
.allMatch(element -> element.contains("h"));
boolean isValidTwo = list.stream()
.noneMatch(element -> element.contains("h"));
assertTrue(isValid);
assertFalse(isValidOne);
assertFalse(isValidTwo);
}
@Test
public void checkStreamReducedValue_whenOperationReduce_thenCorrect() {
void checkStreamReducedValue_whenOperationReduce_thenCorrect() {
List<Integer> integers = new ArrayList<>();
integers.add(1);
integers.add(1);
integers.add(1);
Integer reduced = integers.stream().reduce(23, (a, b) -> a + b);
Integer reduced = integers.stream()
.reduce(23, (a, b) -> a + b);
assertTrue(reduced == 26);
}
@Test
public void checkStreamContains_whenOperationCollect_thenCorrect() {
List<String> resultList = list.stream().map(element -> element.toUpperCase()).collect(Collectors.toList());
void checkStreamContains_whenOperationCollect_thenCorrect() {
List<String> resultList = list.stream()
.map(element -> element.toUpperCase())
.collect(Collectors.toList());
assertEquals(resultList.size(), list.size());
assertTrue(resultList.contains(""));
}
@Test
public void checkParallelStream_whenDoWork() {
list.parallelStream().forEach(element -> doWork(element));
list.parallelStream()
.forEach(element -> doWork(element));
}
private void doWork(String string) {
@@ -0,0 +1,106 @@
package com.baeldung.nthsubstring;
import org.junit.jupiter.api.Test;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class FindNthSubstringIndexUnitTest {
// "0 8 16 24 "
private final static String INPUT = "a word, a word, a word, a word";
@Test
void whenCallingIndexOfTwice_thenGetTheSecondSubstringIndex() {
int firstIdx = INPUT.indexOf("a");
int result = INPUT.indexOf("a", firstIdx + "a".length());
assertEquals(8, result);
}
// the recursive approach
static int nthIndexOf(String input, String substring, int nth) {
if (nth == 1) {
return input.indexOf(substring);
} else {
return input.indexOf(substring, nthIndexOf(input, substring, nth - 1) + substring.length());
}
}
@Test
void whenCallingRecursiveMethod_thenGetTheExpectedResult() {
int result1 = nthIndexOf(INPUT, "a", 1);
assertEquals(0, result1);
int result2 = nthIndexOf(INPUT, "a", 2);
assertEquals(8, result2);
int result3 = nthIndexOf(INPUT, "a", 3);
assertEquals(16, result3);
int result4 = nthIndexOf(INPUT, "a", 4);
assertEquals(24, result4);
int result5 = nthIndexOf(INPUT, "a", 5);
assertEquals(-1, result5);
}
// loop-based approach
static int nthIndexOf2(String input, String substring, int nth) {
int index = -1;
while (nth > 0) {
index = input.indexOf(substring, index + substring.length());
if (index == -1) {
return -1;
}
nth--;
}
return index;
}
@Test
void whenCallingLoopBasedMethod_thenGetTheExpectedResult() {
int result1 = nthIndexOf2(INPUT, "a", 1);
assertEquals(0, result1);
int result2 = nthIndexOf2(INPUT, "a", 2);
assertEquals(8, result2);
int result3 = nthIndexOf2(INPUT, "a", 3);
assertEquals(16, result3);
int result4 = nthIndexOf2(INPUT, "a", 4);
assertEquals(24, result4);
int result5 = nthIndexOf2(INPUT, "a", 5);
assertEquals(-1, result5);
}
static int nthOccurrenceIndex(String input, String regexPattern, int nth) {
Matcher matcher = Pattern.compile(regexPattern).matcher(INPUT);
for (int i = 0; i < nth; i++) {
if (!matcher.find()) {
return -1;
}
}
return matcher.start();
}
@Test
void whenCallingRegexBasedMethod_thenGetTheExpectedResult() {
int result1 = nthOccurrenceIndex(INPUT, "a", 1);
assertEquals(0, result1);
int result2 = nthOccurrenceIndex(INPUT, "a", 2);
assertEquals(8, result2);
int result3 = nthOccurrenceIndex(INPUT, "a", 3);
assertEquals(16, result3);
int result4 = nthOccurrenceIndex(INPUT, "a", 4);
assertEquals(24, result4);
int result5 = nthOccurrenceIndex(INPUT, "a", 5);
assertEquals(-1, result5);
}
}
@@ -54,6 +54,11 @@
<artifactId>commons-codec</artifactId>
<version>${commons-codec.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring-core.version}</version>
</dependency>
</dependencies>
<build>
@@ -95,6 +100,7 @@
<javax.el-api.version>3.0.0</javax.el-api.version>
<javax.el.version>2.2.6</javax.el.version>
<commons-codec.version>1.14</commons-codec.version>
<spring-core.version>5.3.0</spring-core.version>
</properties>
</project>
@@ -3,6 +3,7 @@ package com.baeldung.emptystrings;
import com.google.common.base.Strings;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import org.springframework.util.ObjectUtils;
import javax.validation.ConstraintViolation;
import javax.validation.Validation;
@@ -109,6 +110,24 @@ public class EmptyStringsUnitTest {
assertFalse(Strings.isNullOrEmpty(blankString));
}
/*
* Spring Core ObjectUtils
*/
@Test
public void givenSomeEmptyString_thenObjectUtilsIsEmptyReturnsTrue() {
assertTrue(ObjectUtils.isEmpty(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenObjectUtilsIsEmptyReturnsFalse() {
assertFalse(ObjectUtils.isEmpty(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenObjectUtilsIsEmptyReturnsFalse() {
assertFalse(ObjectUtils.isEmpty(blankString));
}
/*
* Bean Validation
*/
@@ -58,7 +58,7 @@
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<opencsv.version>4.1</opencsv.version>
<opencsv.version>5.8</opencsv.version>
<spring-core.version>5.3.13</spring-core.version>
<apache-commons-lang3.version>3.12.0</apache-commons-lang3.version>
<apache-commons-text.version>1.10.0</apache-commons-text.version>

Some files were not shown because too many files have changed in this diff Show More