I've been doing some XPages development recently, and I was frustrated by some inconvenience in doing server-side validation using JavaScript.
The typical way of doing a series of validations on the same field, is to have a message and condition for each test, e.g.:
<xp:inputText id="inputText1"> <xp:this.validators> <xp:validateRequired message="This here is a required field."> </xp:validateRequired> <xp:validateExpression message="The item must be at least 3 characters"> <xp:this.expression><![CDATA[#{javascript:(value.trim().length >= 3)}]]></xp:this.expression> </xp:validateExpression> <xp:validateExpression message="RTC must be followed by four digits."> <xp:this.expression> var valu:string = value.trim(); var exp = new RegExp("^rtc[0-9]{4}$", "i"); return (!valu.startsWithIgnoreCase("rtc") || valu.match(exp) );}]]></xp:this.expression> </xp:validateExpression> </xp:this.validators> ...
If the validation might result in multiple mesages, you have to split it up according to which message you want to display, and often end up repeating some work with each condition (such as trimming the string in this case, or testing some other fields to see whether there are some restrictions on this one). You can't put all the validation code into one tidy little subroutine in a server JavaScript library.
Of course, you could have one piece of code that returns true or false and also assigns a viewScope variable that would be read by a computed message element, but that's a little kludgy. I found the customValidator element, and the linked article is nice if you want to do validations in Java. But I preferred to add the code to an existing JavaScript library. Fortunately for me, I have access to the people who designed this stuff, so I asked them how to do it and they told me about a couple of system functions I never found in my searching! So, you can start with the following code which includes those calls:
function postValidationError(control, msg) { // msg is the error message string; control is the component being validated // ('this' from the caller). if ((typeof msg) != "string") return; var msgObj = new javax.faces.application.FacesMessage( javax.faces.application.FacesMessage.SEVERITY_ERROR, msg, msg ); facesContext.addMessage(control.getClientId(facesContext), msgObj); control.setValid(false); }
Put that in your JavaScript library, then write multiple tests in a single piece of JavaScript code, such as:
...<xp:this.validators><xp:customValidator> <xp:this.validate><![CDATA[#{javascript: var val = value.trim(); if (val.length < 3) postValidationError(this, "The item must be at least 3 characters"); else if (valu.startsWithIgnoreCase("rtc")) { var exp = new RegExp("^rtc[0-9]{4}$", "i"); if (!val.match(exp)) { postValidationError(this, "RTC must be followed by four digits."); } } }]]></xp:this.validate></xp:customValidator>...
To make things a little simpler, the postValidationError checks the datatype of the msg argument, so you can write a validation function that returns null when valid (or true or any non-string), or the message if not valid. Then you can call postValidationError unconditionally with this return value, and it'll do something appropriate. Note that for a custom validator, the return value is ignored; if you don't do anything to flag the control as invalid, it's assumed to be valid.
Beware <script> in XPages
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notes client
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Delete empty folders, take 2
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@IsNotesBrowserPlugin
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Are Apple customers allowed to marry non-Apple users?
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Searching for design elements 100 times faster
Tue, Jan 8th 2013 9:40a Andre Guirard Often, entries in this blog are in reaction to questions I get, or someone else's code I've run across. One of the reasons things have been so quiet here is that my job has changed so that's not happening as often. But every now and them I'm reminded that there are things I know that it hadn't occurred to me weren't obvious, until I run across another developer who didn't know it. That's the case with this tip. Someone mentioned that it was taking their code a long time to scan mail file [read] Keywords: ldd
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Speak at Pulse?
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Why inboxes fail
Wed, Jun 13th 2012 6:53p Andre Guirard I've been doing some research recently into what causes email to fail to be delivered into inboxes, although it is visible in the All Documents view. I was concerned with this mainly because the recommended corrective action (copy compact) isn't an option for SmartCloud Notes users and their local admins, who don't have access to the users' mail servers to issue console commands. Conventional wisdom, and our technotes, claim that the problem is that the "inbox index gets corrupted". But it [read] Keywords: admin
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notes
notes client
bug
database
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You can read a story of mine...
Thu, May 10th 2012 6:10a Andre Guirard In the recent anthology Sky-Tinted Waters from SamsDot, my story "Misprint" appears. It's about a young stage magician and a trick that works a little too well, and the dangers of not reading ahead to the end of the instructions. The other stories are also very good and I'm enjoying reading it. I hope a bunch of you will buy copies, and that you'll find the stories entertaining. No ebook version is planned at present. [read] Keywords: ldd
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