Add method Result.isSuccessfulNonEmpty() to verify that result is successful and non empty.

Author: amatkivskiy

result/src/main/java/com/amatkivskiy/result/Result.java

@@ -23,6 +23,13 @@ public abstract class Result<V, E> {
    */
   public abstract boolean isEmpty();
 
+  /**
+   * @return true if successful non empty @{@link Result}, false otherwise.
+   */
+  public boolean isSuccessfulNonEmpty() {
+    return isSuccess() && !isEmpty();
+  }
+
   // Syntactic sugar
 
   /**

result/src/test/java/com/amatkivskiy/result/ResultTests.java

@@ -235,6 +235,16 @@ public class ResultTests {
     assertThat(Result.<String, String>failure(OOOH_NOOO).or(OOOH_YEAH), is(OOOH_YEAH));
   }
 
+  @Test public void testIsSuccessfulAndEmptyCorrect() throws Exception {
+    assertThat(Result.success(null).isSuccessfulNonEmpty(), is(false));
+
+    assertThat(Result.success(1).isSuccessfulNonEmpty(), is(true));
+
+    assertThat(Result.failure(1).isSuccessfulNonEmpty(), is(false));
+
+    assertThat(Result.failure(null).isSuccessfulNonEmpty(), is(false));
+  }
+
   static class DefaultThrowerImpl<T> implements Function<T> {
     @Override public T call() {
       return null;