adding new article BAEL-7497 source codes

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hajk1 2024-04-03 01:32:44 +03:30
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commit 4bdfd9699f
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## Core Java Collections Cookbooks and Examples
### Relevant Articles:
- More articles: [[<-- prev]](/core-java-modules/core-java-collections-5)

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package com.baeldung.iteratorvsforeach;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertIterableEquals;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Stream;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
class IteratorVsForeachUnitTest {
private static Stream<Arguments> listProvider() {
return Stream.of(
Arguments.of(
List.of("String1", "String2", "unwanted"),
List.of("String1", "String2"))
);
}
@Test
public void givenEmptyCollection_whenUsingForEach_thenNoElementsAreIterated() {
List<String> names = Collections.emptyList();
StringBuilder stringBuilder = new StringBuilder();
names.forEach(stringBuilder::append);
assertEquals("", stringBuilder.toString());
}
@ParameterizedTest
@MethodSource("listProvider")
public void givenCollectionWithElements_whenRemovingElementDuringForEachIteration_thenElementIsRemoved(
List<String> input, List<String> expected) {
List<String> mutableList = new ArrayList<>(input);
// Separate collection for items to be removed
List<String> toRemove = new ArrayList<>();
// Using forEach to identify items to remove
input.forEach(item -> {
if (item.equals("unwanted")) {
toRemove.add(item);
}
});
// Removing the identified items from the original list
mutableList.removeAll(toRemove);
assertIterableEquals(expected, mutableList);
}
@ParameterizedTest
@MethodSource("listProvider")
public void givenCollectionWithElements_whenRemovingElementDuringIteratorIteration_thenElementIsRemoved(
List<String> input, List<String> expected) {
List<String> mutableList = new ArrayList<>(input);
Iterator<String> it = mutableList.iterator();
while (it.hasNext()) {
String item = it.next();
if (item.equals("unwanted")) {
it.remove(); // Safely remove item
}
}
assertIterableEquals(expected, mutableList);
}
}