Make interfaces Serializable

javaslang/src/main/java/javaslang/collection/Map.java

@@ -11,6 +11,7 @@
 import javaslang.Tuple3;
 import javaslang.control.Option;
 
+import java.io.Serializable;
 import java.util.*;
 import java.util.function.*;
 
@@ -82,7 +83,7 @@
  * @author Daniel Dietrich, Ruslan Sennov
  * @since 2.0.0
  */
-public interface Map<K, V> extends Traversable<Tuple2<K, V>>, Function1<K, V> {
+public interface Map<K, V> extends Traversable<Tuple2<K, V>>, Function1<K, V>, Serializable {
 
     long serialVersionUID = 1L;
 

javaslang/src/main/java/javaslang/collection/Multimap.java

@@ -8,6 +8,7 @@
 import javaslang.*;
 import javaslang.control.Option;
 
+import java.io.Serializable;
 import java.util.*;
 import java.util.function.*;
 
@@ -73,7 +74,7 @@
  * @author Ruslan Sennov
  * @since 2.1.0
  */
-public interface Multimap<K, V> extends Traversable<Tuple2<K, V>>, Function1<K, Traversable<V>>, Kind2<Multimap<?, ?>, K, V> {
+public interface Multimap<K, V> extends Traversable<Tuple2<K, V>>, Function1<K, Traversable<V>>, Kind2<Multimap<?, ?>, K, V>, Serializable {
 
     long serialVersionUID = 1L;
 

javaslang/src/main/java/javaslang/collection/Seq.java

@@ -11,6 +11,7 @@
 import javaslang.Tuple3;
 import javaslang.control.Option;
 
+import java.io.Serializable;
 import java.util.Comparator;
 import java.util.Objects;
 import java.util.function.*;
@@ -87,7 +88,7 @@
  * @author Daniel Dietrich
  * @since 1.1.0
  */
-public interface Seq<T> extends Traversable<T>, Function1<Integer, T> {
+public interface Seq<T> extends Traversable<T>, Function1<Integer, T>, Serializable {
 
     long serialVersionUID = 1L;
 

javaslang/src/main/java/javaslang/collection/Set.java

@@ -10,6 +10,7 @@
 import javaslang.Tuple3;
 import javaslang.control.Option;
 
+import java.io.Serializable;
 import java.util.Comparator;
 import java.util.Spliterator;
 import java.util.Spliterators;
@@ -69,7 +70,7 @@
  * @author Daniel Dietrich, Ruslan Sennov
  * @since 2.0.0
  */
-public interface Set<T> extends Traversable<T>, Function1<T, Boolean> {
+public interface Set<T> extends Traversable<T>, Function1<T, Boolean>, Serializable {
 
     long serialVersionUID = 1L;
 

javaslang/src/main/java/javaslang/collection/Traversable.java

@@ -10,6 +10,7 @@
 import javaslang.Value;
 import javaslang.control.Option;
 
+import java.io.Serializable;
 import java.math.BigInteger;
 import java.util.Comparator;
 import java.util.NoSuchElementException;

javaslang/src/main/java/javaslang/collection/Tree.java

@@ -27,7 +27,9 @@
  * @author Daniel Dietrich, Grzegorz Piwowarek
  * @since 1.1.0
  */
-public interface Tree<T> extends Traversable<T> {
+public interface Tree<T> extends Traversable<T>, Serializable {
+
+    long serialVersionUID = 1L;
 
     /**
      * Returns a {@link java.util.stream.Collector} which may be used in conjunction with

javaslang/src/main/java/javaslang/control/Either.java

@@ -42,7 +42,9 @@
  * @author Daniel Dietrich
  * @since 1.0.0
  */
-public interface Either<L, R> extends Value<R> {
+public interface Either<L, R> extends Value<R>, Serializable {
+
+    long serialVersionUID = 1L;
 
     /**
      * Constructs a {@link Right}

javaslang/src/main/java/javaslang/control/Option.java

@@ -34,7 +34,9 @@
  * @author Daniel Dietrich
  * @since 1.0.0
  */
-public interface Option<T> extends Value<T> {
+public interface Option<T> extends Value<T>, Serializable {
+
+    long serialVersionUID = 1L;
 
     /**
      * Creates a new {@code Option} of a given value.

javaslang/src/main/java/javaslang/control/Try.java

@@ -28,7 +28,9 @@
  * @author Daniel Dietrich
  * @since 1.0.0
  */
-public interface Try<T> extends Value<T> {
+public interface Try<T> extends Value<T>, Serializable {
+
+    long serialVersionUID = 1L;
 
     /**
      * Creates a Try of a CheckedSupplier.

javaslang/src/main/java/javaslang/control/Validation.java

@@ -61,7 +61,9 @@
  * @see <a href="https://github.com/scalaz/scalaz/blob/series/7.3.x/core/src/main/scala/scalaz/Validation.scala">Validation</a>
  * @since 2.0.0
  */
-public interface Validation<E, T> extends Value<T> {
+public interface Validation<E, T> extends Value<T>, Serializable {
+
+    long serialVersionUID = 1L;
 
     /**
      * Creates a {@link Valid} that contains the given {@code value}.

javaslang/src/test/java/javaslang/AbstractValueTest.java

@@ -98,7 +98,7 @@ protected StringAssert assertThat(String actual) {
     @SuppressWarnings("unchecked")
     abstract protected <T> Value<T> of(T... elements);
 
-    // TODO: Eliminate this method. Switching the behavior of unit tests is evil. Tests should not contain additional logic.
+    // TODO: Eliminate this method. Switching the behavior of unit tests is evil. Tests should not contain additional logic. Also it seems currently to be used in different sematic contexts.
     abstract protected boolean useIsEqualToInsteadOfIsSameAs();
 
     // returns the peek result of the specific Traversable implementation
@@ -981,14 +981,14 @@ private boolean isSerializable() {
                         instanceOf(Either.LeftProjection.class),
                         instanceOf(Either.RightProjection.class),
                         instanceOf(Future.class),
-                        instanceOf(Iterator.class),
-                        instanceOf(Validation.class)
+                        instanceOf(Iterator.class)
                 ), false),
                 Case(anyOf(
                         instanceOf(Either.class),
                         instanceOf(Option.class),
                         instanceOf(Try.class),
-                        instanceOf(Traversable.class)
+                        instanceOf(Traversable.class),
+                        instanceOf(Validation.class)
                 ), true)
         );
         assertThat(actual).isEqualTo(expected);

javaslang/src/test/java/javaslang/control/ValidationTest.java

@@ -40,7 +40,7 @@ protected final <T> Value<T> of(T... elements) {
 
     @Override
     protected boolean useIsEqualToInsteadOfIsSameAs() {
-        return false;
+        return true;
     }
 
     @Override