Add helper methods for Optionals.

diff --git a/src/main/java/net/pterodactylus/sone/utils/Optionals.java b/src/main/java/net/pterodactylus/sone/utils/Optionals.java
new file mode 100644 (file)
index 0000000..67132aa
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/utils/Optionals.java
@@ -0,0 +1,32 @@
+package net.pterodactylus.sone.utils;
+
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+import com.google.common.base.Predicate;
+
+/**
+ * Helper methods for dealing with {@link Optional}s.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class Optionals {
+
+       public static Predicate<Optional<?>> isPresent() {
+               return new Predicate<Optional<?>>() {
+                       @Override
+                       public boolean apply(Optional<?> input) {
+                               return input.isPresent();
+                       }
+               };
+       }
+
+       public static <T> Function<Optional<T>, T> get() {
+               return new Function<Optional<T>, T>() {
+                       @Override
+                       public T apply(Optional<T> input) {
+                               return input.get();
+                       }
+               };
+       }
+
+}

diff --git a/src/test/java/net/pterodactylus/sone/utils/OptionalsTest.java b/src/test/java/net/pterodactylus/sone/utils/OptionalsTest.java
new file mode 100644 (file)
index 0000000..0f7dee3
--- /dev/null
+++ b/src/test/java/net/pterodactylus/sone/utils/OptionalsTest.java
@@ -0,0 +1,52 @@
+package net.pterodactylus.sone.utils;
+
+import java.util.Arrays;
+import java.util.List;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.FluentIterable;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Unit test for {@link Optionals}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class OptionalsTest {
+
+       private final Object object1 = new Object();
+       private final Object object2 = new Object();
+       private final Object object3 = new Object();
+
+       @Test
+       public void canCreateOptionals() {
+               new Optionals();
+       }
+
+       @Test
+       public void isPresentFiltersCorrectOptionals() {
+               List<Optional<Object>> optionals = Arrays.asList(
+                               Optional.of(object1), Optional.absent(),
+                               Optional.of(object2), Optional.absent(),
+                               Optional.of(object3), Optional.absent()
+               );
+               List<Optional<Object>> filteredOptionals =
+                               FluentIterable.from(optionals).filter(Optionals.isPresent()).toList();
+               MatcherAssert.assertThat(filteredOptionals, Matchers.contains(
+                               Optional.of(object1), Optional.of(object2), Optional.of(object3)));
+       }
+
+       @Test
+       public void getReturnsCorrectValues() {
+               List<Optional<Object>> optionals = Arrays.asList(
+                               Optional.of(object1),
+                               Optional.of(object2),
+                               Optional.of(object3)
+               );
+               List<Object> objects = FluentIterable.from(optionals).transform(Optionals.get()).toList();
+               MatcherAssert.assertThat(objects, Matchers.contains(object1, object2, object3));
+       }
+
+}