NIFI-1785 added NON_BLANK_VALIDATOR

NIFI-1785 addressed PR comment

NIFI-1785 fixed white spaces

This closes #365.

Signed-off-by: Bryan Bende <bbende@apache.org>

nifi-commons/nifi-processor-utilities/src/main/java/org/apache/nifi/processor/util/StandardValidators.java

@@ -127,6 +127,9 @@ public class StandardValidators {
 
     public static final Validator PORT_VALIDATOR = createLongValidator(1, 65535, true);
 
+    /**
+     * {@link Validator} that ensures that value's length > 0
+     */
     public static final Validator NON_EMPTY_VALIDATOR = new Validator() {
         @Override
         public ValidationResult validate(final String subject, final String value, final ValidationContext context) {
@@ -134,6 +137,20 @@ public class StandardValidators {
         }
     };
 
+    /**
+     * {@link Validator} that ensures that value has 1+ non-whitespace
+     * characters
+     */
+    public static final Validator NON_BLANK_VALIDATOR = new Validator() {
+        @Override
+        public ValidationResult validate(final String subject, final String value, final ValidationContext context) {
+            return new ValidationResult.Builder().subject(subject).input(value)
+                    .valid(value != null && !value.trim().isEmpty())
+                    .explanation(subject
+                    + " must contain at least one character that is not white space").build();
+        }
+    };
+
     public static final Validator BOOLEAN_VALIDATOR = new Validator() {
         @Override
         public ValidationResult validate(final String subject, final String value, final ValidationContext context) {

nifi-commons/nifi-processor-utilities/src/test/java/org/apache/nifi/processor/util/TestStandardValidators.java

@@ -18,6 +18,7 @@ package org.apache.nifi.processor.util;
 
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
 
 import java.util.concurrent.TimeUnit;
 
@@ -29,6 +30,20 @@ import org.mockito.Mockito;
 
 public class TestStandardValidators {
 
+    @Test
+    public void testNonBlankValidator() {
+        Validator val = StandardValidators.NON_BLANK_VALIDATOR;
+        ValidationContext vc = mock(ValidationContext.class);
+        ValidationResult vr = val.validate("foo", "", vc);
+        assertFalse(vr.isValid());
+
+        vr = val.validate("foo", "    ", vc);
+        assertFalse(vr.isValid());
+
+        vr = val.validate("foo", "    h", vc);
+        assertTrue(vr.isValid());
+    }
+
     @Test
     public void testTimePeriodValidator() {
         Validator val = StandardValidators.createTimePeriodValidator(1L, TimeUnit.SECONDS, Long.MAX_VALUE, TimeUnit.NANOSECONDS);