I’m currently working on rewriting my multiple-file uploader using Xpages/ custom controls. I encountered a problem when embedding the control on an Xpage based form. When the “save” button on the form is called, the uploads are started but I needed the Xpage to wait until all files had been uploaded.
My first try was to implement a sleep function in Javascript, but the only way this seemed to work was using a while loop. The big problem with that is that it eats up all CPU cycles and “locks” your browser. Not a good solution.
One of the articles I read mentioned the Java sleep method. This gave me the idea of implementing the wait-until function on the Xpage itself.
In the querySaveDocument event of the datasource on the Xpage I make a (conditional) call to the Java sleep method:
while (!condition) {
java.lang.Thread.currentThread().sleep(1000);
//re-check condition here
}
This causes the Xpage to wait for (in this case) 1 second (1000 milliseconds) until it continues to save the document.
To make sure that the script doesn’t go in an infinite loop I have included a timeout period:
var startTime = new Date().getTime();
var elapsedTime = 0;
var timeOutSeconds = 60;
while (!condition && elapsedTime < timeOutSeconds) {
java.lang.Thread.currentThread().sleep(1000);
//re-check condition here
elapsedTime = (new Date().getTime() - startTime) / 1024;
}