added support to consumers and mappers

src/main/java/com/johnnywey/flipside/failable/Failable.java

@@ -2,6 +2,11 @@
 
 import com.johnnywey.flipside.marker.DidItWork;
 
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
 /**
  * This is a simple wrapper for communicating failure data. It is loosely based on a Scala Option but provides
  * a common interface for failure cases that can be easily mapped to things like HTTP codes, etc.
@@ -12,4 +17,27 @@ public interface Failable<T> {
     Fail getReason();
     String getDetail();
     DidItWork toDidItWork();
+    default void ifSuccess(Consumer<? super T> consumer) {
+        if (isSuccess() && get() != null) {
+            consumer.accept(get());
+        } else {
+            throw new FailableException(this);
+        }
+    }
+    default void ifFailed(Consumer<Fail> consumer) {
+        if (!isSuccess()) {
+            consumer.accept(getReason());
+        }
+    }
+    Failable<T> filter(Predicate<? super T> predicate);
+    <U> Failable<U> map(Function<? super T, ? extends U> mapper);
+    <U> Failable<U> flatMap(Function<? super T, Failable<U>> mapper);
+    default T orElse(T other) {
+        return get() != null ? get() : other;
+    }
+    default T orElseGet(Supplier<? extends T> other) {
+        return get() != null ? get() : other.get();
+    }
+
+
 }

src/main/java/com/johnnywey/flipside/failable/Failed.java

@@ -2,11 +2,14 @@
 
 import com.johnnywey.flipside.marker.DidNotWork;
 import com.johnnywey.flipside.marker.DidItWork;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
 
 /**
  * Something failed.
  */
-public class Failed<T> implements Failable<T> {
+public final class Failed<T> implements Failable<T> {
 
     private final Fail reason;
     private final String detail;
@@ -16,6 +19,10 @@ public Failed(final Fail reason, final String detail) {
         this.detail = detail;
     }
 
+    public static <T> Failed<T> of(final Fail reason, final String detail) {
+        return new Failed<>(reason, detail);
+    }
+
     @Override
     public T get() {
         throw new FailableException(this);
@@ -45,4 +52,29 @@ public String toString() {
     public DidItWork toDidItWork() {
         return new DidNotWork(this.reason, this.detail);
     }
+
+    @Override
+    public Failable<T> filter(Predicate<? super T> predicate) {
+        return this;
+    }
+
+    @Override
+    public <U> Failable<U> map(Function<? super T, ? extends U> mapper) {
+        throw new FailableException(this);
+    }
+
+    @Override
+    public <U> Failable<U> flatMap(Function<? super T, Failable<U>> mapper) {
+        throw new FailableException(this);
+    }
+
+    @Override
+    public T orElse(T other) {
+        throw new FailableException(this);
+    }
+
+    @Override
+    public T orElseGet(Supplier<? extends T> other) {
+        throw new FailableException(this);
+    }
 }

src/main/java/com/johnnywey/flipside/failable/Success.java

@@ -3,11 +3,16 @@
 import com.johnnywey.flipside.marker.Worked;
 import com.johnnywey.flipside.marker.DidItWork;
 
+import java.util.Objects;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
 /**
  * Something succeeded.
  */
 public class Success<T> implements Failable<T> {
     private final T result;
+    private static final Success<?> EMPTY = new Success<>(null);
 
     public Success(final T result) {
         this.result = result;
@@ -18,6 +23,16 @@ public T get() {
         return result;
     }
 
+    public static <T> Success<T> of(final T result) {
+        return new Success<>(result);
+    }
+
+    public static<T> Success<T> empty() {
+        @SuppressWarnings("unchecked")
+        Success<T> t = (Success<T>) EMPTY;
+        return t;
+    }
+
     @Override
     public Boolean isSuccess() {
         return true;
@@ -37,4 +52,34 @@ public String getDetail() {
     public DidItWork toDidItWork() {
         return new Worked();
     }
+
+    @Override
+    public Failable<T> filter(Predicate<? super T> predicate) {
+        Objects.requireNonNull(predicate);
+        if (!isSuccess()) {
+            return this;
+        } else {
+            return predicate.test(get()) ? this : empty();
+        }
+    }
+
+    @Override
+    public <U> Failable<U> map(Function<? super T, ? extends U> mapper) {
+        Objects.requireNonNull(mapper);
+        if (!isSuccess())
+            return empty();
+        else {
+            return Success.of(mapper.apply(get()));
+        }
+    }
+
+    @Override
+    public <U> Failable<U> flatMap(Function<? super T, Failable<U>> mapper)  {
+        Objects.requireNonNull(mapper);
+        if (!isSuccess())
+            return empty();
+        else {
+            return Objects.requireNonNull(mapper.apply(get()));
+        }
+    }
 }

src/test/groovy/com/johnnywey/flipside/FailedSpec.groovy

@@ -0,0 +1,38 @@
+package com.johnnywey.flipside
+
+import com.johnnywey.flipside.failable.Fail
+import com.johnnywey.flipside.failable.FailableException
+import com.johnnywey.flipside.failable.Failed
+import spock.lang.Specification
+
+class FailedSpec extends Specification {
+
+    def "test failed"() {
+        setup:
+        def errMsg = "This is a test failed"
+        def unit = Failed.of(Fail.BAD_REQUEST, errMsg)
+
+        expect:
+        !unit.isSuccess()
+        unit.detail.matches(errMsg)
+        unit.reason.equals(Fail.BAD_REQUEST)
+        unit.toString().equals(Failed.of(Fail.BAD_REQUEST, errMsg).toString())
+        unit.reason.httpResponseCode.equals(Fail.BAD_REQUEST.httpResponseCode)
+
+        unit.toDidItWork().detail.matches(errMsg)
+        unit.toDidItWork().reason.equals(Fail.BAD_REQUEST)
+    }
+
+    def "test exception"() {
+        setup:
+        def errMsg = "This is a test failed"
+        def unit = Failed.of(Fail.BAD_REQUEST, errMsg)
+
+        when:
+        unit.get()
+
+        then:
+        thrown(FailableException)
+    }
+
+}

src/test/groovy/com/johnnywey/flipside/SuccessSpec.groovy

@@ -0,0 +1,40 @@
+package com.johnnywey.flipside
+
+import com.johnnywey.flipside.failable.Fail
+import com.johnnywey.flipside.failable.Success
+import spock.lang.Specification
+
+class SuccessSpec extends Specification {
+
+    def "test success"() {
+        setup:
+        def successMsg = "mySuccess"
+        def unit = Success.of(successMsg)
+
+        expect:
+        unit.isSuccess()
+        unit.reason.equals(Fail.SUCCESS)
+        unit.detail.equals(Fail.SUCCESS.name())
+        unit.get().equals(successMsg)
+        unit.toDidItWork().isSuccess()
+    }
+
+    def "test success with consumer"() {
+        setup:
+        def successMsg = "mySuccess"
+        def result = "not set"
+        Success.of(successMsg).ifSuccess({ m -> result = successMsg })
+
+        expect:
+        result == successMsg
+    }
+
+    def "test success with mapping"() {
+        setup:
+        def successMsg = "mySuccess"
+        Double result = Success.of(successMsg).map({s -> 23d}).orElse(24d);
+
+        expect:
+        result == 23d
+    }
+}