Update example to use Closure

Signed-off-by: Gopal S Akshintala <gopala.akshintala@salesforce.com>

Author: overfullstack

README.adoc

@@ -125,17 +125,27 @@ ifdef::env-github[]
 [source,java,indent=0,options="nowrap"]
 .link:{testdir}/com/salesforce/vador/execution/VadorTest.java[VadorTest.java, tag=withValidators]
 ----
-final Validator<Bean, ValidationFailure> validator1 = bean -> NONE;
-final Validator<Bean, ValidationFailure> validator2 = bean -> NONE;
-final Validator<Bean, ValidationFailure> validator3 = bean -> UNKNOWN_EXCEPTION;
-final List<Validator<Bean, ValidationFailure>> validatorChain =
-    List.of(validator1, validator2, validator3);
-final var validationConfig =
-    ValidationConfig.<Bean, ValidationFailure>toValidate()
-        .withValidators(Tuple.of(validatorChain, NONE))
-        .prepare();
-final var result = Vador.validateAndFailFast(VALIDATABLE, validationConfig);
-assertThat(result).contains(UNKNOWN_EXCEPTION);
+@Test
+void failFastWithFirstFailureWithValidator() {
+  // tag::withValidators[]
+  final List<Validator<Bean, ValidationFailure>> validatorChain =
+      List.of(validator(1, 9), validator(3, 7), validator(5, 5));
+  final var validationConfig =
+      ValidationConfig.<Bean, ValidationFailure>toValidate()
+          .withValidators(Tuple.of(validatorChain, NONE))
+          .prepare();
+  // end::withValidators[]
+  final var result = Vador.validateAndFailFast(new Bean(0), validationConfig);
+  assertThat(result).contains(OUT_OF_BOUND);
+}
+
+/**
+ * You can pass any number of arguments (like lowerLimit, upperLimit),
+ * to write your validator closure
+ */
+Validator<Bean, ValidationFailure> validator(int lowerLimit, int upperLimit) {
+  return bean -> bean.value >= lowerLimit && bean.value <= upperLimit ? NONE :  OUT_OF_BOUND;
+}
 ----
 
 endif::[]

vador/src/test/java/com/salesforce/vador/execution/VadorTest.java

@@ -10,6 +10,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static sample.consumer.failure.ValidationFailure.NONE;
 import static sample.consumer.failure.ValidationFailure.NOTHING_TO_VALIDATE;
+import static sample.consumer.failure.ValidationFailure.OUT_OF_BOUND;
 import static sample.consumer.failure.ValidationFailure.UNKNOWN_EXCEPTION;
 import static sample.consumer.failure.ValidationFailure.VALIDATION_FAILURE_1;
 import static sample.consumer.failure.ValidationFailure.VALIDATION_FAILURE_2;
@@ -34,18 +35,23 @@ class VadorTest {
   @Test
   void failFastWithFirstFailureWithValidator() {
     // tag::withValidators[]
-    final Validator<Bean, ValidationFailure> validator1 = bean -> NONE;
-    final Validator<Bean, ValidationFailure> validator2 = bean -> NONE;
-    final Validator<Bean, ValidationFailure> validator3 = bean -> UNKNOWN_EXCEPTION;
     final List<Validator<Bean, ValidationFailure>> validatorChain =
-        List.of(validator1, validator2, validator3);
+        List.of(validator(1, 9), validator(3, 7), validator(5, 5));
     final var validationConfig =
         ValidationConfig.<Bean, ValidationFailure>toValidate()
             .withValidators(Tuple.of(validatorChain, NONE))
             .prepare();
     // end::withValidators[]
-    final var result = Vador.validateAndFailFast(VALIDATABLE, validationConfig);
-    assertThat(result).contains(UNKNOWN_EXCEPTION);
+    final var result = Vador.validateAndFailFast(new Bean(0), validationConfig);
+    assertThat(result).contains(OUT_OF_BOUND);
+  }
+
+  /**
+   * You can pass any number of arguments (like lowerLimit, upperLimit), to write your validator
+   * closure
+   */
+  Validator<Bean, ValidationFailure> validator(int lowerLimit, int upperLimit) {
+    return bean -> bean.value >= lowerLimit && bean.value <= upperLimit ? NONE : OUT_OF_BOUND;
   }
 
   // end::failFastDemo[]
@@ -146,7 +152,7 @@ void throwableMapperTest() {
 
   @Value
   private static class Bean {
-    int id;
+    int value;
   }
 
   @Value

vador/src/test/java/sample/consumer/failure/ValidationFailure.java

@@ -57,6 +57,8 @@ public class ValidationFailure {
       new ValidationFailure(ValidationFailureMessage.INVALID_UDD_ID_3);
   public static final ValidationFailure INVALID_MEMBER =
       new ValidationFailure(ValidationFailureMessage.INVALID_CHILD);
+  public static final ValidationFailure OUT_OF_BOUND =
+      new ValidationFailure(ValidationFailureMessage.UNKNOWN_EXCEPTION);
   public static final ValidationFailure UNKNOWN_EXCEPTION =
       new ValidationFailure(ValidationFailureMessage.UNKNOWN_EXCEPTION);
   public static final ValidationFailure VALIDATION_FAILURE_1 =

vador/src/test/java/sample/consumer/failure/ValidationFailureMessage.java

@@ -45,6 +45,7 @@ public enum ValidationFailureMessage {
   INVALID_CHILD(Section.COMMON_VALIDATION_FAILURE, "InvalidChild"),
   INVALID_MEMBER(Section.COMMON_VALIDATION_FAILURE, "InvalidMember"),
   UNKNOWN_EXCEPTION("", ""),
+  OUT_OF_BOUND("", ""),
   VALIDATION_FAILURE_1("", ""),
   VALIDATION_FAILURE_2("", ""),
   VALIDATION_FAILURE_3("", ""),