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Merge pull request #6153 from cror/stream-count 

BAEL-2546: Stream.count
This commit is contained in:
Loredana Crusoveanu 2019-01-18 23:20:22 +02:00 committed by GitHub
parent af9a60bddf 735b0a10b2
commit 8a4c326357
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3 changed files with 76 additions and 3 deletions
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2
java-streams/src/main/java/com/baeldung/stream/filter/Customer.java
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@ -32,7 +32,7 @@ public class Customer {
return this.points > points;
}
public boolean hasOverThousandPoints() {
public boolean hasOverHundredPoints() {
return this.points > 100;
}

72
java-streams/src/test/java/com/baeldung/stream/filter/StreamCountUnitTest.java Normal file
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@ -0,0 +1,72 @@
package com.baeldung.stream.filter;
import org.junit.Test;
import org.junit.Before;
import java.util.Arrays;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;
public class StreamCountUnitTest {
private List<Customer> customers;
@Before
public void setUp() {
Customer john = new Customer("John P.", 15, "https://images.unsplash.com/photo-1543320485-d0d5a49c2b2e");
Customer sarah = new Customer("Sarah M.", 200);
Customer charles = new Customer("Charles B.", 150);
Customer mary = new Customer("Mary T.", 1, "https://images.unsplash.com/photo-1543297057-25167dfc180e");
customers = Arrays.asList(john, sarah, charles, mary);
}
@Test
public void givenListOfCustomers_whenCount_thenGetListSize() {
long count = customers
.stream()
.count();
assertThat(count).isEqualTo(4L);
}
@Test
public void givenListOfCustomers_whenFilterByPointsOver100AndCount_thenGetTwo() {
long countBigCustomers = customers
.stream()
.filter(c -> c.getPoints() > 100)
.count();
assertThat(countBigCustomers).isEqualTo(2L);
}
@Test
public void givenListOfCustomers_whenFilterByPointsAndNameAndCount_thenGetOne() {
long count = customers
.stream()
.filter(c -> c.getPoints() > 10 && c.getName().startsWith("Charles"))
.count();
assertThat(count).isEqualTo(1L);
}
@Test
public void givenListOfCustomers_whenNoneMatchesFilterAndCount_thenGetZero() {
long count = customers
.stream()
.filter(c -> c.getPoints() > 500)
.count();
assertThat(count).isEqualTo(0L);
}
@Test
public void givenListOfCustomers_whenUsingMethodOverHundredPointsAndCount_thenGetTwo() {
long count = customers
.stream()
.filter(Customer::hasOverHundredPoints)
.count();
assertThat(count).isEqualTo(2L);
}
}

5
java-streams/src/test/java/com/baeldung/stream/filter/StreamFilterUnitTest.java
View File

@ -62,7 +62,7 @@ public class StreamFilterUnitTest {
List<Customer> customersWithMoreThan100Points = customers
.stream()
.filter(Customer::hasOverThousandPoints)
.filter(Customer::hasOverHundredPoints)
.collect(Collectors.toList());
assertThat(customersWithMoreThan100Points).hasSize(2);
@ -81,7 +81,7 @@ public class StreamFilterUnitTest {
.flatMap(c -> c
.map(Stream::of)
.orElseGet(Stream::empty))
.filter(Customer::hasOverThousandPoints)
.filter(Customer::hasOverHundredPoints)
.collect(Collectors.toList());
assertThat(customersWithMoreThan100Points).hasSize(2);
@ -156,4 +156,5 @@ public class StreamFilterUnitTest {
})
.collect(Collectors.toList())).isInstanceOf(RuntimeException.class);
}
}