Question

I needs some tips on this one, since I couldn’t find anything on this, though it’s probably pretty simple to do, but I can’t think of a way.
Ok, so I need a hidden field which will automatically compute so called id numbers for every document, the numbers must start from 00001 and forward and must never ever repeat. For instance i create a document with numberId = 00001 and another document which creates numberId = 00002, if I ever delete the first or second document, the third created document should have numberId = 00003. No matter how many documents get deleted, the next document created should get the latest numberId and add 1 to it.

I hope I was clear about what I need here. I need an advice or a tip on how would I achieve this.

Also, I can’t use @Unique.

Answer 1

Here is the code that you will need based on some of the comments to the question.

function simplegetSequentialNumber(){
    synchronized(applicationScope){
        var newSeqNum:Int = 0;
        if (applicationScope.containsKey("seqNumber")){
            newSeqNum = applicationScope.get("seqNumber") + 1;
            applicationScope.put("seqNumber",  newSeqNum);
            var seqView:NotesView = database.getView("vw_SequentialNumberStore");
            var seqNumberDoc:NotesDocument = seqView.getFirstDocument();
            seqNumberDoc.replaceItemValue("seqNumber",applicationScope.get("seqNumber"));
            seqNumberDoc.save(true,true);
        } else {
            var seqView:NotesView = database.getView("vw_SequentialNumberStore");
            try {
                var seqNumberDoc:NotesDocument = seqView.getFirstDocument();
                applicationScope.put("seqNumber",seqNumberDoc.getItemValueInteger("seqNumber") + 1);
                seqNumberDoc.replaceItemValue("seqNumber",applicationScope.get("seqNumber"));
                seqNumberDoc.save(true,true);
                newSeqNum = applicationScope.get("seqNumber");
            } catch(e) {
                var seqNumberDoc:NotesDocument = database.createDocument();
                seqNumberDoc.replaceItemValue("Form","cPanel");
                seqNumberDoc.replaceItemValue("seqNumber",1);
                applicationScope.put("seqNumber", 1);
                seqNumberDoc.save(true,true);
                newSeqNum = 1;
            }
        }
    }
    var seqNNNN:String = ("0000" + newSeqNum.toString()).slice(-4);
    return seqNNNN;
}

As you can see it first gets the next sequential number in a synchronized block, adds one to it and then puts the number back into the applicationScope.

Then it converts it to the string, adds the additional 4 zeros and then the right 4 characters from it. This returns a string and needs to be stored in a text field. You cannot store it in a number field because Notes will automatically drop the leading zeros from the value.

You can test this function by adding it to a server side javascript library and then including it in a simple page that runs a repeat control to repeat a computed field that just calls the function. Here is my test page.

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core">
    <xp:this.resources>
        <xp:script src="/seqNum.jss" clientSide="false" />
    </xp:this.resources>
    <xp:repeat id="repeat1" rows="30" value="#{javascript:30}">
        <xp:text escape="true" id="computedField1"
            value="#{javascript:simplegetSequentialNumber();}" />
        <xp:br id="br1" />
    </xp:repeat>
</xp:view>