{"id":611,"date":"2011-10-21T17:18:00","date_gmt":"2011-10-21T17:18:00","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/2012\/10\/parametrizing-custom-validator-in-jsf-2.html"},"modified":"2012-10-21T20:25:43","modified_gmt":"2012-10-21T20:25:43","slug":"parametrizing-custom-validator-in-jsf-2","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2011\/10\/parametrizing-custom-validator-in-jsf-2.html","title":{"rendered":"Parametrizing custom validator in JSF 2"},"content":{"rendered":"
Writing a custom validator in JSF 2 is not a complicated task. You implement Validator<\/em> interface, add @FacesValidator<\/em> annotation and insert validator declaration in faces-config.xml<\/em>, that\u2019s all. A piece of cake. But let\u2019s consider following scenario:<\/p>\n

You need custom date validator, let\u2019s say checking that date from rich:calendar<\/em> is not in the past. So we place calendar component with validator inside.<\/p>\n

<rich:calendar value=\"#{fieldValue}\" id=\"dateField\" datePattern=\"yyyy\/MM\/dd\">\r\n        <f:validator validatorId=\"dateNotInThePast\"\/>\r\n    <\/rich:calendar>\r\n<\/pre>\n
And our  validator could look like below:<\/p>\n
@FacesValidator(\"dateNotInThePast\")\r\npublic class DateNotInThePastValidator implements Validator {\r\n\r\n  @Override\r\n  public void validate(FacesContext facesContext, UIComponent uiComponent, Object value)\r\n                                                              throws ValidatorException {\r\n    if (ObjectUtil.isNotEmpty(value)) {\r\n      checkDate((Date)value, uiComponent, facesContext.getViewRoot().getLocale());\r\n    }\r\n  }\r\n\r\n  private void checkDate(Date date, UIComponent uiComponent, Locale locale) {\r\n    if(isDateInRange(date) == false) {\r\n      ResourceBundle rb = ResourceBundle.getBundle(\"messages\", locale);\r\n      String messageText = rb.getString(\"date.not.in.the.past\");\r\n      throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,\r\n                                     messageText, messageText));\r\n    }\r\n  }\r\n\r\n  private boolean isDateInRange(Date date) {\r\n    Date today = new DateTime().withTime(0, 0, 0, 0).toDate();\r\n    return date.after(today) || date.equals(today);\r\n  }\r\n}\r\n<\/pre>\n
And if we provide key value in properties file we will see something like this:<\/p>\n
\"\"<\/a><\/div>\n
So it looks that we have working and production-ready custom validator.
 
<\/div> <\/div><\/p>\n
  The problem<\/h3>\n
But while our form becomes more and more complex we might encouter issue described on the screen below:<\/p>\n
\"\"<\/a><\/div>\n
So the problem is how user can determine which date is valid and which is not? Our validator uses the same property key to display both error messages.<\/p>\n
  The solution<\/h3>\n
We need to somehow provide a label of validated field to our custom validator. And, suprisingly for JSF, it can be achieved pretty easily. The only catch is that you have to know how to do it \":)\" <\/p>\n
So in Java Server Faces we could parametrize components with attributes (f:attribute<\/em> tag). So we add attribute to rich:calendar and then read this passed value value inside validator assigned to this calendar field. So now our calendar components should look like that:<\/p>\n
<rich:calendar value=\"#{fieldValue}\" id=\"dateField\" datePattern=\"yyyy\/MM\/dd\">\r\n        <f:validator validatorId=\"dateNotInThePast\"\/>\r\n        <f:attribute name=\"fieldLabel\" value=\"Date field 2\" \/>\r\n    <\/rich:calendar>\r\n<\/pre>\n
And in our validator Java class we could get this value using uiComponent.getAttributes().get(\u201cfieldLabel\u201d);<\/em><\/p>\n
private void checkDate(Date date, UIComponent uiComponent, Locale locale) {\r\n        if(isDateInRange(date) == false) {\r\n            ResourceBundle rb = ResourceBundle.getBundle(\"messages\", locale);\r\n            String messageText = getFieldLabel(uiComponent) +\" \" + rb.getString(getErrorKey());\r\n\r\n            throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,\r\n                                            messageText, messageText));\r\n        }\r\n    }\r\n\r\n    protected String getFieldLabel(UIComponent uiComponent) {\r\n        String fieldLabel = (String) uiComponent.getAttributes().get(\"fieldLabel\");\r\n\r\n        if(fieldLabel == null) {\r\n            fieldLabel = \"Date\" ;\r\n        }\r\n\r\n        return fieldLabel;\r\n    }\r\n<\/pre>\n
Our property value for error should have value can not be in the past<\/em> as Date<\/em> or field label will be added at the beginning of error message.<\/p>\n
And working example should show something similar to this screen:<\/p>\n
\"\"<\/a><\/div>\n
Reference: <\/i><\/strong>Parametrizing custom validator in JSF 2<\/a> from our JCG partner<\/a> Tomasz Dziurko<\/a> at the Code Hard Go Pro<\/a> blog<\/p>\n
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