Validation through the Validatable interface

You can set the ValidatorFilter as a global filter so that all actions that implement the Validatable interface will be validated.

And the internationalized messages would be inside the /validation/MyAction_loc.i18n file, where loc is the locale (ex: MyAction_en_US.i18n). OBS: If you are using a master i18n file through LocaleManager.useMasterI18N(true), then your messages will be inside the /i18n/master_en_US.i18n.

Now if you don't want to put your messages in a separate file, then you can just hardcode your messages:

public class MyAction implements Validatable {
    
    public String execute() throws Exception {
        
        // your action stuff here...
        
    }
    
    public void prepareValidator(Validator val, String innerAction) {
        
            Rule required = RequiredFieldRule.getInstance();
        
            val.add("username", required, FIELD_REQUIRED_ERROR);
            val.add("username", StringRule.getInstance(6, 30), INVALID_USERNAME_LENGTH);
        
            val.add("age", required, FIELD_REQUIRED_ERROR);
            val.add("age", IntegerRule.getInstance(18, 50), INVALID_AGE);
        
            val.add("password", required, FIELD_REQUIRED_ERROR);
            val.add("password", StringRule.getInstance(4, 20), INVALID_PASSWORD_LENGTH);
            val.add("password", EqualRule.getInstance("password", "passconf"), PASSWORD_DOES_NOT_MATCH);
        
            val.add("passconf", required, FIELD_REQUIRED_ERROR);
            
    }
    
    private static final String FIELD_REQUIRED_ERROR = "Field required!";
    private static final String INVALID_USERNAME_LENGTH = "Username length invalid!";
    private static final String INVALID_AGE = "Invalid age!";
    private static final String INVALID_PASSWORD_LENGTH = "Invalide password length!";
    private static final String PASSWORD_DOES_NOT_MATCH = "Passwords do not match!";
}

Now to display your message in the JSP, you can use the menta tag. You can choose from mtw:hasError and mtw:outError tag.

Note that this tags are conditional tags, in other words, nothing will be shown if there is no error for the field.

To add the ValidatorFilter as a global filter in the application manager you can just do that:

TIP: Use the Mentawai HTML form tags mtw:input, mtw:select, etc. so you don't have to worry about re-displaying the values that the user typed in case of validation error. We know you don't want to place a bunch of scriptlets in your JSPs to do this.