values should be integers in Java

Encoding Quick Response Code in Java values should be integers

floatRange: Checks whether a field s value is within a range Specify vars as min and max with the beginning and ending values allowed The values should be of the type float creditCard: Checks whether the field is a valid credit card number

Confirms a credit card number as a valid American Express, Visa, Master Card, or Discover credit card

Now that you know about validators and the syntax of the validation xml file, you can create your own validationxml to validate LoginForm The LoginForm example has two fields to validate: userName and password Listing 9-4 shows the entire validationxml file

Listing 9-4

< xml version= 10 encoding= ISO-8859-1 > <!DOCTYPE form-validation PUBLIC -//Apache Software Foundation//DTD Commons Validator Rules Configuration 101//EN http://jakartaapacheorg/commons/dtds/validator_1_0_1dtd > 1 <form-validation> 2 <!-- ========== Form Definitions ===================== --> 3 <formset> (continued)

Listing 9-4 (continued)

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 <form name= loginForm > <field property= userName depends= required > <arg0 key= errorusernamerequired /> </field> <field property= password depends= required,minlength > <arg0 key= errorpasswordrequired /> <arg1 key= ${var:minlength} name= minlength resource= false /> <var> <var-name>minlength</var-name> <var-value>5</var-value> </var> </field>

<field property= password depends= maxlength > <arg0 key= errorpasswordrequired /> <arg1 key= ${var:maxlength} name= maxlength resource= false /> 22 <var> 23 <var-name>maxlength</var-name> 24 <var-value>8</var-value> 25 </var> 26 </field> 27 </form> 28 </formset> 29</form-validation>

Note the following lines in Listing 9-4: Line 4: You must define each form that the Validator needs to validate with a <form> tag This line specifies that the loginForm is to be validated Lines 5 8: You need to define each field in the form that needs validating with a <field> tag These lines accomplish this definition for the userName field Line 6: The userName field is defined as a required field, nothing more The depends attribute on this line is equal to required, the name of the rule to invoke when validating the field The required validator checks to make sure that the value of the field is neither null nor an empty string Line 7: Specifies argument one to be passed to the default message resource The default message resource is

Therefore, the arg0 value functions as a key to look up a message in the default message resource bundle Instead of {0}, the user sees that mes sage in the default error message

Line 9: Defines the password field i as the next field to validate This field has two validators, required and minlength Both tests have to pass before the field is validated The required validator does the same function as for the previous username field The minlength validator checks to make sure that the length of the string is greater than or equal to some minimum length The minimum length is specified with a <var> tag var-name has to be minlength var-value must be an integer value indicating the minimum length to check against The default error mes sage for minlength is

Lines 11 and 12: The default message takes two parameters, a field name and a minimum length These lines define these two parameters The interesting point here is the dual use of the arg0 value Because the code specifies two validators, the arg values must apply to them both As luck would have it, arg0 can fit for the default error message for either the required validator or the minlength validator Lines 13 16: Define the minimum length of the password to be 5

Lines 18 26: Define the maximum length of the password field to be 8 characters We defined the password field twice because we also wanted to use the maxlength validator However, the default messages for minlength and maxlength both specify {1} as the length value The dilemma is that arg1 can take only one value To get around this thorny problem, we chose to define the password field twice The second time we applied only the maxlength validator and gave the maximum allowed value for the arg1 value The validationxml file is now complete and ready to use with the updated Login application