Move failure handling Predicates to AbstractPolicy

src/main/java/net/jodah/failsafe/AbstractPolicy.java

@@ -6,6 +6,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.BiPredicate;
 
 /**
@@ -64,7 +65,7 @@ public R handle(List<Class<? extends Throwable>> failures) {
     Assert.notNull(failures, "failures");
     Assert.isTrue(!failures.isEmpty(), "failures cannot be empty");
     failuresChecked = true;
-    failureConditions.add(Predicates.failurePredicateFor(failures));
+    failureConditions.add(failurePredicateFor(failures));
     return (R) this;
   }
 
@@ -76,7 +77,7 @@ public R handle(List<Class<? extends Throwable>> failures) {
   public R handleIf(Predicate<? extends Throwable> failurePredicate) {
     Assert.notNull(failurePredicate, "failurePredicate");
     failuresChecked = true;
-    failureConditions.add(Predicates.failurePredicateFor(failurePredicate));
+    failureConditions.add(failurePredicateFor(failurePredicate));
     return (R) this;
   }
 
@@ -97,7 +98,7 @@ public <T> R handleIf(BiPredicate<T, ? extends Throwable> resultPredicate) {
    * Specifies that a failure has occurred if the {@code result} matches the execution result.
    */
   public R handleResult(Object result) {
-    failureConditions.add(Predicates.resultPredicateFor(result));
+    failureConditions.add(resultPredicateFor(result));
     return (R) this;
   }
 
@@ -108,7 +109,7 @@ public R handleResult(Object result) {
    */
   public <T> R handleResultIf(Predicate<T> resultPredicate) {
     Assert.notNull(resultPredicate, "resultPredicate");
-    failureConditions.add(Predicates.resultPredicateFor(resultPredicate));
+    failureConditions.add(resultPredicateFor(resultPredicate));
     return (R) this;
   }
 
@@ -150,4 +151,53 @@ public boolean isFailure(Object result, Throwable failure) {
     // Fail by default if a failure is not checked by a condition
     return failure != null && !failuresChecked;
   }
+
+  /**
+   * Returns a predicate that evaluates whether the {@code result} equals an execution result.
+   */
+  static BiPredicate<Object, Throwable> resultPredicateFor(final Object result) {
+    return (t, u) -> Objects.equals(result, t);
+  }
+
+  /**
+   * Returns a predicate that evaluates the {@code failurePredicate} against a failure.
+   */
+  @SuppressWarnings("unchecked")
+  static BiPredicate<Object, Throwable> failurePredicateFor(final Predicate<? extends Throwable> failurePredicate) {
+    return (t, u) -> u != null && ((Predicate<Throwable>) failurePredicate).test(u);
+  }
+
+  /**
+   * Returns a predicate that evaluates the {@code resultPredicate} against a result, when present.
+   *
+   * Short-circuts to false without invoking {@code resultPredicate},
+   * when result is not present (i.e. BiPredicate.test(null, Throwable)).
+   */
+  @SuppressWarnings("unchecked")
+  static <T> BiPredicate<Object, Throwable> resultPredicateFor(final Predicate<T> resultPredicate) {
+    return (t, u) -> {
+      if (u == null) {
+        return ((Predicate<Object>) resultPredicate).test(t);
+      } else {
+        // resultPredicate is only defined over the success type.
+        // It doesn't know how to handle a failure of type Throwable,
+        // so we return false here.
+        return false;
+      }
+    };
+  }
+
+  /**
+   * Returns a predicate that returns whether any of the {@code failures} are assignable from an execution failure.
+   */
+  static BiPredicate<Object, Throwable> failurePredicateFor(final List<Class<? extends Throwable>> failures) {
+    return (t, u) -> {
+      if (u == null)
+        return false;
+      for (Class<? extends Throwable> failureType : failures)
+        if (failureType.isAssignableFrom(u.getClass()))
+          return true;
+      return false;
+    };
+  }
 }

src/main/java/net/jodah/failsafe/RetryPolicy.java

@@ -141,7 +141,7 @@ public <T> RetryPolicy abortIf(BiPredicate<T, ? extends Throwable> completionPre
    */
   public <T> RetryPolicy abortIf(Predicate<T> resultPredicate) {
     Assert.notNull(resultPredicate, "resultPredicate");
-    abortConditions.add(Predicates.resultPredicateFor(resultPredicate));
+    abortConditions.add(resultPredicateFor(resultPredicate));
     return this;
   }
 
@@ -181,7 +181,7 @@ public RetryPolicy abortOn(Class<? extends Throwable>... failures) {
   public RetryPolicy abortOn(List<Class<? extends Throwable>> failures) {
     Assert.notNull(failures, "failures");
     Assert.isTrue(!failures.isEmpty(), "failures cannot be empty");
-    abortConditions.add(Predicates.failurePredicateFor(failures));
+    abortConditions.add(failurePredicateFor(failures));
     return this;
   }
 
@@ -192,15 +192,15 @@ public RetryPolicy abortOn(List<Class<? extends Throwable>> failures) {
    */
   public RetryPolicy abortOn(Predicate<? extends Throwable> failurePredicate) {
     Assert.notNull(failurePredicate, "failurePredicate");
-    abortConditions.add(Predicates.failurePredicateFor(failurePredicate));
+    abortConditions.add(failurePredicateFor(failurePredicate));
     return this;
   }
 
   /**
    * Specifies that retries should be aborted if the execution result matches the {@code result}.
    */
   public RetryPolicy abortWhen(Object result) {
-    abortConditions.add(Predicates.resultPredicateFor(result));
+    abortConditions.add(resultPredicateFor(result));
     return this;
   }
 

src/test/java/net/jodah/failsafe/PredicatesTest.java → src/test/java/net/jodah/failsafe/AbstractPolicyTest.java

@@ -21,9 +21,9 @@
 import java.util.function.BiPredicate;
 
 @Test
-public class PredicatesTest {
+public class AbstractPolicyTest {
   public void testResultPredicateOnlyHandlesResults() {
-    BiPredicate<Object, Throwable> resultPredicate = Predicates.resultPredicateFor(result -> true);
+    BiPredicate<Object, Throwable> resultPredicate = AbstractPolicy.resultPredicateFor(result -> true);
     Assert.assertTrue(resultPredicate.test("result", null));
     Assert.assertFalse(resultPredicate.test(null, new RuntimeException()));
   }