OptionalRules

SUGGESTION

Simplification

View source code on GitHub

Suppression

Disable all rules by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$).* as compiler argument.

OptionalOfNullable

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalOfNullable") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalOfNullable).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testOptionalOfNullable() {
-    return ImmutableSet.of(
-        toString() == null ? Optional.empty() : Optional.of(toString()),
-        toString() != null ? Optional.of(toString()) : Optional.empty());
+    return ImmutableSet.of(Optional.ofNullable(toString()), Optional.ofNullable(toString()));
   }

OptionalIsEmpty

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalIsEmpty") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalIsEmpty).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Boolean> testOptionalIsEmpty() {
-    return ImmutableSet.of(!Optional.empty().isPresent(), !Optional.of("foo").isPresent());
+    return ImmutableSet.of(Optional.empty().isEmpty(), Optional.of("foo").isEmpty());
   }

OptionalIsPresent

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalIsPresent") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalIsPresent).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Boolean> testOptionalIsPresent() {
-    return ImmutableSet.of(!Optional.empty().isEmpty(), !Optional.of("foo").isEmpty());
+    return ImmutableSet.of(Optional.empty().isPresent(), Optional.of("foo").isPresent());
   }

OptionalOrElseThrow

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalOrElseThrow") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalOrElseThrow).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 String testOptionalOrElseThrow() {
-    return Optional.of("foo").get();
+    return Optional.of("foo").orElseThrow();
   }

OptionalOrElseThrowMethodReference

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalOrElseThrowMethodReference") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalOrElseThrowMethodReference).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Function<Optional<Integer>, Integer> testOptionalOrElseThrowMethodReference() {
-    return Optional::get;
+    return Optional::orElseThrow;
   }

OptionalFirstIteratorElement

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalFirstIteratorElement") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalFirstIteratorElement).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testOptionalFirstIteratorElement() {
     return ImmutableSet.of(
-        ImmutableSet.of("foo").iterator().hasNext()
-            ? Optional.of(ImmutableSet.of("foo").iterator().next())
-            : Optional.empty(),
-        !ImmutableSet.of("foo").iterator().hasNext()
-            ? Optional.empty()
-            : Optional.of(ImmutableSet.of("foo").iterator().next()));
+        stream(ImmutableSet.of("foo").iterator()).findFirst(),
+        stream(ImmutableSet.of("foo").iterator()).findFirst());
   }

TernaryOperatorOptionalPositiveFiltering

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("TernaryOperatorOptionalPositiveFiltering") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$TernaryOperatorOptionalPositiveFiltering).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<String> testTernaryOperatorOptionalPositiveFiltering() {
-    return "foo".length() > 5 ? Optional.of("foo") : Optional.empty();
+    return /* Or Optional.ofNullable (can't auto-infer). */ Optional.of("foo")
+        .filter(v -> v.length() > 5);
   }

TernaryOperatorOptionalNegativeFiltering

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("TernaryOperatorOptionalNegativeFiltering") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$TernaryOperatorOptionalNegativeFiltering).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<String> testTernaryOperatorOptionalNegativeFiltering() {
-    return "foo".length() > 5 ? Optional.empty() : Optional.of("foo");
+    return /* Or Optional.ofNullable (can't auto-infer). */ Optional.of("foo")
+        .filter(v -> v.length() <= 5);
   }

MapOptionalToBoolean

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("MapOptionalToBoolean") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$MapOptionalToBoolean).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Boolean> testMapOptionalToBoolean() {
     return ImmutableSet.of(
-        Optional.of("foo").map(String::isEmpty).orElse(false),
-        Optional.of("bar").map(s -> s.isEmpty()).orElse(Boolean.FALSE));
+        Optional.of("foo").filter(String::isEmpty).isPresent(),
+        Optional.of("bar").filter(s -> s.isEmpty()).isPresent());
   }

MapToNullable

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("MapToNullable") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$MapToNullable).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testMapToNullable() {
     return ImmutableSet.of(
-        Optional.of(1).flatMap(n -> Optional.of(String.valueOf(n))),
-        Optional.of(2).flatMap(n -> Optional.ofNullable(String.valueOf(n))));
+        Optional.of(1).map(n -> String.valueOf(n)), Optional.of(2).map(n -> String.valueOf(n)));
   }

FlatMapToOptional

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("FlatMapToOptional") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$FlatMapToOptional).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<String> testFlatMapToOptional() {
-    return Optional.of(1).map(n -> Optional.of(String.valueOf(n)).orElseThrow());
+    return Optional.of(1).flatMap(n -> Optional.of(String.valueOf(n)));
   }

OrOrElseThrow

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OrOrElseThrow") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OrOrElseThrow).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 String testOrOrElseThrow() {
-    return Optional.of("foo").orElseGet(() -> Optional.of("bar").orElseThrow());
+    return Optional.of("foo").or(() -> Optional.of("bar")).orElseThrow();
   }

StreamFlatMapOptional

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("StreamFlatMapOptional") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$StreamFlatMapOptional).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Object> testStreamFlatMapOptional() {
     return ImmutableSet.of(
-        Stream.of(Optional.empty()).filter(Optional::isPresent).map(Optional::orElseThrow),
-        Stream.of(Optional.of("foo")).flatMap(Streams::stream));
+        Stream.of(Optional.empty()).flatMap(Optional::stream),
+        Stream.of(Optional.of("foo")).flatMap(Optional::stream));
   }

StreamMapToOptionalGet

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("StreamMapToOptionalGet") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$StreamMapToOptionalGet).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Stream<String> testStreamMapToOptionalGet() {
-    return Stream.of(1).map(n -> Optional.of(String.valueOf(n)).orElseThrow());
+    return Stream.of(1).flatMap(n -> Optional.of(String.valueOf(n)).stream());
   }

FilterOuterOptionalAfterFlatMap

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("FilterOuterOptionalAfterFlatMap") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$FilterOuterOptionalAfterFlatMap).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<Integer> testFilterOuterOptionalAfterFlatMap() {
-    return Optional.of("foo").flatMap(v -> Optional.of(v.length()).filter(len -> len > 0));
+    return Optional.of("foo").flatMap(v -> Optional.of(v.length())).filter(len -> len > 0);
   }

MapOuterOptionalAfterFlatMap

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("MapOuterOptionalAfterFlatMap") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$MapOuterOptionalAfterFlatMap).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<Integer> testMapOuterOptionalAfterFlatMap() {
-    return Optional.of("foo").flatMap(v -> Optional.of(v.length()).map(len -> len * 0));
+    return Optional.of("foo").flatMap(v -> Optional.of(v.length())).map(len -> len * 0);
   }

FlatMapOuterOptionalAfterFlatMap

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("FlatMapOuterOptionalAfterFlatMap") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$FlatMapOuterOptionalAfterFlatMap).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<Integer> testFlatMapOuterOptionalAfterFlatMap() {
-    return Optional.of("foo").flatMap(v -> Optional.of(v.length()).flatMap(Optional::of));
+    return Optional.of("foo").flatMap(v -> Optional.of(v.length())).flatMap(Optional::of);
   }

OptionalOrOtherOptional

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalOrOtherOptional") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalOrOtherOptional).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testOptionalOrOtherOptional() {
     return ImmutableSet.of(
-        Optional.of("foo").map(Optional::of).orElse(Optional.of("bar")),
-        Optional.of("baz").map(Optional::of).orElseGet(() -> Optional.of("qux")),
-        Stream.of(Optional.of("quux"), Optional.of("quuz")).flatMap(Optional::stream).findFirst());
+        Optional.of("foo").or(() -> Optional.of("bar")),
+        Optional.of("baz").or(() -> Optional.of("qux")),
+        Optional.of("quux").or(() -> Optional.of("quuz")));
   }

OptionalIdentity

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalIdentity") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalIdentity).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testOptionalIdentity() {
     return ImmutableSet.of(
-        Optional.of("foo").stream().findFirst(),
-        Optional.of("bar").stream().findAny(),
-        Optional.of("baz").stream().min(String::compareTo),
-        Optional.of("qux").stream().max(String::compareTo));
+        Optional.of("foo"), Optional.of("bar"), Optional.of("baz"), Optional.of("qux"));
   }

OptionalFilter

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalFilter") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalFilter).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 ImmutableSet<Optional<String>> testOptionalFilter() {
     return ImmutableSet.of(
-        Optional.of("foo").stream().filter(String::isEmpty).findFirst(),
-        Optional.of("bar").stream().filter(String::isEmpty).findAny());
+        Optional.of("foo").filter(String::isEmpty), Optional.of("bar").filter(String::isEmpty));
   }

OptionalMap

SUGGESTION

Simplification

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalMap") to the enclosing element.

Disable this rule by adding -XepOpt:Refaster:NamePattern=^(?!OptionalRules\$OptionalMap).* as compiler argument.

Samples

Shows the difference in example code before and after the Refaster rule is applied.

 Optional<String> testOptionalMap() {
-    return Optional.of(1).stream().map(String::valueOf).findAny();
+    return Optional.of(1).map(String::valueOf);
   }