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Merge branch 'master' of https://github.com/eugenp/tutorials

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Eugen Paraschiv 2018-12-18 23:50:31 +02:00
parent 8411df4e6b c042348d93
commit 53abf6733d
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core-java-8/src/test/java/com/baeldung/java8/Java8PredicateChainUnitTest.java Normal file
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package com.baeldung.java8;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.contains;
import static org.junit.Assert.assertEquals;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import org.junit.Test;
public class Java8PredicateChainUnitTest {
private List<String> names = Arrays.asList("Adam", "Alexander", "John", "Tom");
@Test
public void whenFilterList_thenSuccess() {
List<String> result = names.stream()
.filter(name -> name.startsWith("A"))
.collect(Collectors.toList());
assertEquals(2, result.size());
assertThat(result, contains("Adam", "Alexander"));
}
@Test
public void whenFilterListWithMultipleFilters_thenSuccess() {
List<String> result = names.stream()
.filter(name -> name.startsWith("A"))
.filter(name -> name.length() < 5)
.collect(Collectors.toList());
assertEquals(1, result.size());
assertThat(result, contains("Adam"));
}
@Test
public void whenFilterListWithComplexPredicate_thenSuccess() {
List<String> result = names.stream()
.filter(name -> name.startsWith("A") && name.length() < 5)
.collect(Collectors.toList());
assertEquals(1, result.size());
assertThat(result, contains("Adam"));
}
@Test
public void whenFilterListWithCombinedPredicatesInline_thenSuccess() {
List<String> result = names.stream()
.filter(((Predicate<String>) name -> name.startsWith("A")).and(name -> name.length() < 5))
.collect(Collectors.toList());
assertEquals(1, result.size());
assertThat(result, contains("Adam"));
}
@Test
public void whenFilterListWithCombinedPredicatesUsingAnd_thenSuccess() {
Predicate<String> predicate1 = str -> str.startsWith("A");
Predicate<String> predicate2 = str -> str.length() < 5;
List<String> result = names.stream()
.filter(predicate1.and(predicate2))
.collect(Collectors.toList());
assertEquals(1, result.size());
assertThat(result, contains("Adam"));
}
@Test
public void whenFilterListWithCombinedPredicatesUsingOr_thenSuccess() {
Predicate<String> predicate1 = str -> str.startsWith("J");
Predicate<String> predicate2 = str -> str.length() < 4;
List<String> result = names.stream()
.filter(predicate1.or(predicate2))
.collect(Collectors.toList());
assertEquals(2, result.size());
assertThat(result, contains("John", "Tom"));
}
@Test
public void whenFilterListWithCombinedPredicatesUsingOrAndNegate_thenSuccess() {
Predicate<String> predicate1 = str -> str.startsWith("J");
Predicate<String> predicate2 = str -> str.length() < 4;
List<String> result = names.stream()
.filter(predicate1.or(predicate2.negate()))
.collect(Collectors.toList());
assertEquals(3, result.size());
assertThat(result, contains("Adam", "Alexander", "John"));
}
@Test
public void whenFilterListWithCollectionOfPredicatesUsingAnd_thenSuccess() {
List<Predicate<String>> allPredicates = new ArrayList<Predicate<String>>();
allPredicates.add(str -> str.startsWith("A"));
allPredicates.add(str -> str.contains("d"));
allPredicates.add(str -> str.length() > 4);
List<String> result = names.stream()
.filter(allPredicates.stream()
.reduce(x -> true, Predicate::and))
.collect(Collectors.toList());
assertEquals(1, result.size());
assertThat(result, contains("Alexander"));
}
@Test
public void whenFilterListWithCollectionOfPredicatesUsingOr_thenSuccess() {
List<Predicate<String>> allPredicates = new ArrayList<Predicate<String>>();
allPredicates.add(str -> str.startsWith("A"));
allPredicates.add(str -> str.contains("d"));
allPredicates.add(str -> str.length() > 4);
List<String> result = names.stream()
.filter(allPredicates.stream()
.reduce(x -> false, Predicate::or))
.collect(Collectors.toList());
assertEquals(2, result.size());
assertThat(result, contains("Adam", "Alexander"));
}
}