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Optional example(Sidorenko_EV) #32

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Optional example(Sidorenko_EV) #32

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206bda2
Opltional done
MYIIIKET Jun 24, 2017
ddee315
Complete
MYIIIKET Jun 25, 2017
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49 changes: 47 additions & 2 deletions src/test/java/option/OptionalExample.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2,9 +2,12 @@

import org.junit.Test;

import java.io.FileNotFoundException;
import java.util.Optional;
import java.util.concurrent.ThreadLocalRandom;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;

import static org.junit.Assert.assertEquals;

Expand Down Expand Up @@ -50,9 +53,51 @@ public void map() {
assertEquals(expected, actual);
}

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Implement zipMap

@Test
public void filter() {
Optional<String> optional = getOptional();
Predicate<String> predicate = String::isEmpty;
Optional<String> actual =
(optional.isPresent() && predicate.test(optional.get())) ? optional : Optional.empty();
Optional<String> expected = optional.filter(predicate);

assertEquals(expected, actual);
}

@Test
public void flatMap() {
Optional<String> optional = getOptional();
Function<String, Optional<String>> function = s -> Optional.of(s.toUpperCase());
Optional<String> actual = (optional.isPresent()) ? function.apply(optional.get()) : Optional.empty();
Optional<String> expected = optional.flatMap(function);

assertEquals(expected, actual);
}

@Test
public void orElse() {
Optional<String> optional = Optional.empty();
String other = null;
String actual = optional.isPresent() ? optional.get() : other;
String expected = optional.orElse(other);

assertEquals(expected, actual);
}

@Test
public void orElseGet() {
Optional<String> optional = Optional.empty();
String toReturn = null;
Supplier<String> stringSupplier = () -> toReturn;
String actual = optional.isPresent() ? optional.get() : stringSupplier.get();
String expected = optional.orElseGet(stringSupplier);

assertEquals(expected, actual);
}

private Optional<String> getOptional() {
return ThreadLocalRandom.current().nextBoolean()
? Optional.empty()
: Optional.of("abc");
? Optional.empty()
: Optional.of("abc");
}
}