Adding Try#toEither(Supplier)) and Either#filterOrElse

README.md

@@ -51,7 +51,7 @@ Then, you can add the dependency to your project.
 <dependency>
   <groupId>com.github.VassilisSoum</groupId>
   <artifactId>FunctionalUtils</artifactId>
-  <version>2.4.0</version>
+  <version>2.8.0</version>
 </dependency>
 ```
 

pom.xml

@@ -6,7 +6,7 @@
 
   <groupId>com.soumakis</groupId>
   <artifactId>FunctionalUtils</artifactId>
-  <version>2.4.0</version>
+  <version>2.8.0</version>
   <packaging>jar</packaging>
 
   <properties>

src/main/java/com/soumakis/control/Either.java

@@ -363,4 +363,12 @@ default <A, B> Either<A, B> biFlatMap(Function<? super L, ? extends Either<A, B>
     }
     return rightFn.apply(getRight());
   }
+
+  default <C> Either<C, R> filterOrElse(Function<? super R, Boolean> predicate,
+      Supplier<C> supplier) {
+    if (isRight() && predicate.apply(getRight())) {
+      return Either.right(getRight());
+    }
+    return Either.left(supplier.get());
+  }
 }

src/main/java/com/soumakis/control/Try.java

@@ -196,6 +196,10 @@ default Either<Throwable, T> toEither() {
     return fold(Either::left, Either::right);
   }
 
+  default <U> Either<U, T> toEither(Supplier<U> leftSupplier) {
+    return fold(__ -> Either.left(leftSupplier.get()), Either::right);
+  }
+
   /**
    * Applies a function to the value if this is a {@code Success}, or a different function if this
    * is a {@code Failure}.

src/test/java/com/soumakis/control/EitherTest.java

@@ -168,4 +168,12 @@ void testBiFlatMapRight() {
     assert (mapped.getRight() == 2);
   }
 
+  @Test
+  void testFilterOrElse() {
+    Either<String, Integer> right = Either.right(42);
+    Either<String, Integer> filtered = right.filterOrElse(n -> n > 42, () -> "error");
+    assert (filtered.isLeft());
+    assert (filtered.getLeft().equals("error"));
+  }
+
 }