Optionals.nonEmpty(String)

Author: fluentfuture

mug/src/main/java/com/google/mu/util/Optionals.java

@@ -105,6 +105,16 @@ public static <C extends Collection<?>> Optional<C> nonEmpty(C collection) {
     return collection.isEmpty() ? Optional.empty() : Optional.of(collection);
   }
 
+  /**
+   * Returns {@code Optional.empty()} if {@code s} is null or empty;
+   * otherwise wraps it with {@link Optional#of}.
+   *
+   * @since 9.9.3
+   */
+  public static <S extends CharSequence> Optional<S> nonEmpty(S s) {
+    return optional(s != null && s.length() > 0, s);
+  }
+
   /**
    * If {@code a} and {@code b} are present, returns a {@code BiOptional} instance containing them;
    * otherwise returns an empty {@code BiOptional}.

mug/src/test/java/com/google/mu/util/OptionalsTest.java

@@ -82,6 +82,18 @@ public class OptionalsTest {
     assertThat(Optionals.nonEmpty(asList(1))).hasValue(asList(1));
   }
 
+  @Test public void nonEmpty_nullString() {
+    assertThat(Optionals.nonEmpty("")).isEmpty();
+  }
+
+  @Test public void nonEmpty_emptyString() {
+    assertThat(Optionals.nonEmpty("")).isEmpty();
+  }
+
+  @Test public void nonEmpty_nonEmptyString() {
+    assertThat(Optionals.nonEmpty("foo")).hasValue("foo");
+  }
+
   @Test public void ifPresent_or_firstIsAbsent_secondSupplierIsPresent() {
     ifPresent(Optional.empty(), consumer::accept)
         .or(() -> ifPresent(Optional.of("left"), Optional.of("right"), action::run))
@@ -256,12 +268,14 @@ public void inOrder_bothStepsArePresent() {
         .setDefault(BiOptional.class, BiOptional.of(1, "one"))
         .ignore(Optionals.class.getMethod("optional", boolean.class, Object.class))
         .ignore(Optionals.class.getMethod("both", Optional.class, Optional.class))
+        .ignore(Optionals.class.getMethod("nonEmpty", CharSequence.class))
         .testAllPublicStaticMethods(Optionals.class);
     new NullPointerTester()
         .setDefault(Optional.class, Optional.of("foo"))
         .setDefault(OptionalInt.class, OptionalInt.of(123))
         .setDefault(OptionalLong.class, OptionalLong.of(123))
         .setDefault(OptionalDouble.class, OptionalDouble.of(123))
+        .ignore(Optionals.class.getMethod("nonEmpty", CharSequence.class))
         .setDefault(BiOptional.class, BiOptional.of(1, "one"))
         .ignore(Optionals.class.getMethod("optional", boolean.class, Object.class))
         .testAllPublicStaticMethods(Optionals.class);