Implemented a WordCountRule

Author: JanHolger

src/main/java/org/javawebstack/validator/Validator.java

@@ -46,6 +46,7 @@ public class Validator {
         registerRuleType("regex",      RegexRule.Validator.class,       RegexRule.class);
         registerRuleType("uuid",       UUIDRule.Validator.class,        UUIDRule.class);
         registerRuleType("charset",    CharsetRule.Validator.class,     CharsetRule.class);
+        registerRuleType("word_count", WordCountRule.Validator.class,   WordCountRule.class);
     }
 
     private final Map<String[], ValidationConfig> rules = new HashMap<>();

src/main/java/org/javawebstack/validator/rule/WordCountRule.java

@@ -0,0 +1,53 @@
+package org.javawebstack.validator.rule;
+
+import org.javawebstack.abstractdata.AbstractElement;
+import org.javawebstack.validator.ValidationContext;
+
+import java.lang.reflect.Field;
+
+public @interface WordCountRule {
+
+    int value();
+    int max() default 1;
+    String separator() default " ";
+
+    class Validator implements ValidationRule {
+
+        private final int min;
+        private final int max;
+        private final String separator;
+
+        public Validator(WordCountRule rule) {
+            this(rule.value(), rule.max(), rule.separator());
+        }
+
+        public Validator(int min, int max, String separator) {
+            this.min = min;
+            this.max = Math.min(min, max);
+            this.separator = separator;
+        }
+
+        public Validator(String[] params) {
+            this(
+                    params.length > 0 ? Integer.parseInt(params[0]) : 1,
+                    params.length > 1 ? Integer.parseInt(params[0]) : 1,
+                    params.length > 2 ? params[2] : " "
+            );
+        }
+
+        public String validate(ValidationContext context, Field field, AbstractElement value) {
+            if (value == null || value.isNull())
+                return null;
+            if (!value.isPrimitive())
+                return "Not a string value";
+            int wordCount = value.string().split(separator).length;
+            if (wordCount < min)
+                return String.format("Less than the minimum word count (%d < %d)", wordCount, min);
+            if (wordCount > max)
+                return String.format("More than maximum word count (%d > %d)", wordCount, max);
+            return null;
+        }
+
+    }
+
+}