Introduce {Mono,Flux}OfType Refaster rules (#810)

PicnicSupermarket · Oct 9, 2023 · 583e51c · 583e51c
1 parent 9ada078
commit 583e51c
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diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java
@@ -1053,6 +1053,32 @@ Flux<S> after(Flux<T> flux) {
     }
   }
 
+  /** Prefer {@link Mono#ofType(Class)} over more contrived alternatives. */
+  static final class MonoOfType<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono, Class<S> clazz) {
+      return mono.filter(clazz::isInstance).cast(clazz);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Mono<T> mono, Class<S> clazz) {
+      return mono.ofType(clazz);
+    }
+  }
+
+  /** Prefer {@link Flux#ofType(Class)} over more contrived alternatives. */
+  static final class FluxOfType<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux, Class<S> clazz) {
+      return flux.filter(clazz::isInstance).cast(clazz);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux, Class<S> clazz) {
+      return flux.ofType(clazz);
+    }
+  }
+
   /** Prefer {@link Mono#flatMap(Function)} over more contrived alternatives. */
   static final class MonoFlatMap<S, T> {
     @BeforeTemplate

diff --git a/...ontrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestInput.java b/...ontrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestInput.java
@@ -364,6 +364,14 @@ Flux<Number> testFluxCast() {
     return Flux.just(1).map(Number.class::cast);
   }
 
+  Mono<Number> testMonoOfType() {
+    return Mono.just(1).filter(Number.class::isInstance).cast(Number.class);
+  }
+
+  Flux<Number> testFluxOfType() {
+    return Flux.just(1).filter(Number.class::isInstance).cast(Number.class);
+  }
+
   Mono<String> testMonoFlatMap() {
     return Mono.just("foo").map(Mono::just).flatMap(identity());
   }

diff --git a/...ntrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestOutput.java b/...ntrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestOutput.java
@@ -357,6 +357,14 @@ Flux<Number> testFluxCast() {
     return Flux.just(1).cast(Number.class);
   }
 
+  Mono<Number> testMonoOfType() {
+    return Mono.just(1).ofType(Number.class);
+  }
+
+  Flux<Number> testFluxOfType() {
+    return Flux.just(1).ofType(Number.class);
+  }
+
   Mono<String> testMonoFlatMap() {
     return Mono.just("foo").flatMap(Mono::just);
   }