add the following rules

- alpha
- alpha_num
- alpha_dash
- email

Co-author-by: Julian Gojani <julian@gojani.xyz>

Author: JWaldecker

pom.xml

@@ -32,6 +32,11 @@
             <version>5.4.2</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.sun.mail</groupId>
+            <artifactId>javax.mail</artifactId>
+            <version>1.6.2</version>
+        </dependency>
     </dependencies>
 
     <build>

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

@@ -36,6 +36,10 @@ public class Validator {
         registerRuleType("date", DateRule.class);
         registerRuleType("array", ArrayRule.class);
         registerRuleType("list", ArrayRule.class);
+        registerRuleType("alpha", AlphaRule.class);
+        registerRuleType("alpha_num", AlphaNumRule.class);
+        registerRuleType("alpha_dash", AlphaDashRule.class);
+        registerRuleType("email", EmailRule.class);
     }
 
     public static void registerRuleType(String name, Class<? extends ValidationRule> type){

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

@@ -0,0 +1,20 @@
+package org.javawebstack.validator.rule;
+
+import org.javawebstack.abstractdata.AbstractElement;
+import org.javawebstack.validator.ValidationContext;
+
+import java.lang.reflect.Field;
+
+public class AlphaDashRule implements ValidationRule {
+    @Override
+    public String validate(ValidationContext context, Field field, AbstractElement value) {
+        if (value == null)
+            return null;
+
+        String pattern = "[A-Za-z0-9-_]*";
+        if (!value.string().matches(pattern))
+            return "Value must only contain alpha-numeric characters as well as dashes and underscores.";
+
+        return null;
+    }
+}

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

@@ -0,0 +1,20 @@
+package org.javawebstack.validator.rule;
+
+import org.javawebstack.abstractdata.AbstractElement;
+import org.javawebstack.validator.ValidationContext;
+
+import java.lang.reflect.Field;
+
+public class AlphaNumRule implements ValidationRule {
+    @Override
+    public String validate(ValidationContext context, Field field, AbstractElement value) {
+        if (value == null)
+            return null;
+
+        String pattern = "[A-Za-z0-9]*";
+        if (!value.string().matches(pattern))
+            return "Value must only contain alpha-numeric characters.";
+
+        return null;
+    }
+}

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

@@ -0,0 +1,20 @@
+package org.javawebstack.validator.rule;
+
+import org.javawebstack.abstractdata.AbstractElement;
+import org.javawebstack.validator.ValidationContext;
+
+import java.lang.reflect.Field;
+
+public class AlphaRule implements ValidationRule {
+    @Override
+    public String validate(ValidationContext context, Field field, AbstractElement value) {
+        if (value == null)
+            return null;
+
+        String pattern = "[A-Za-z]*";
+        if (!value.string().matches(pattern))
+            return "Value must only contain alphabetic characters.";
+
+        return null;
+    }
+}

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

@@ -0,0 +1,25 @@
+package org.javawebstack.validator.rule;
+
+import org.javawebstack.abstractdata.AbstractElement;
+import org.javawebstack.validator.ValidationContext;
+
+import javax.mail.internet.AddressException;
+import javax.mail.internet.InternetAddress;
+import java.lang.reflect.Field;
+
+public class EmailRule implements ValidationRule {
+    @Override
+    public String validate(ValidationContext context, Field field, AbstractElement value) {
+        if (value == null)
+            return null;
+
+        try {
+            InternetAddress emailAddr = new InternetAddress(value.string());
+            emailAddr.validate();
+        } catch (AddressException ex) {
+            return "Value is not a valid email address";
+        }
+
+        return null;
+    }
+}