Managing Glide Lists

[Chuck Tomasi]

A colleague of mine recently asked for some assistance in managing Glide List (glide_list) fields. I had written some scripts that were fairly task specific so I rewrote them as generic as possible and share them here.

Glide List fields are a field that can hold many reference values at a time (as opposed a reference field that holds just one value.) The most familiar example of a glide list is the Watch list field on the task table (incident, problem, change, etc.) However, this script works on any glide_list.

Behind the scenes, the system is storing these values as comma separate sys_ids. Occasionally, it becomes necessary to manage the data in that field. For example, one might want to:

• Know if a user exists in the list
• Add a new user to the list
• Delete a user from the list 

For that, I created the following script include I call ListUtil. This is based on an example given at Knowledge 11. I added a _debug function and a generous amount of comments to describe each function.

To use the ListUtil class, create a new object and pass the field (values) you want to manage:

var lu = new ListUtil(current.watch_list);

Here is a summary of the functions (methods) available:

• isInList(id) - returns true/false if id is in the list
• addToList(id) - adds id to the list if it doesn't already exist
• removeFromList(id) - removes id from the list
• getList() - returns the comma separated string of the current list (e.g. to save back to current.watch_list) 

var ListUtil = Class.create();
ListUtil.prototype = {

      initialize: function(list) {

              this.debug = gs.getProperty('debug.ListUtil') == 'true';

              if (JSUtil.notNil(list)) {
                      this._list = list.split(',');
              } else {
                      this._list = [];
              }
      },

/*
* isInList - check if an id is in the list
*
* @param id - sys_id to look for
* @return - boolean
* @uses - this._list
*
*/
      isInList : function(id) {

              var i = this._getIndex(id);

              this._debug('isInList(' + i + '): looking for ' + id + ' in ' + this.getList());
              return (i > -1);
      },

/*
* addToList - add an id to the list
*
* @param id - sys_id of the id to add
* @return - NA
* @uses - this._list
*
*/
      addToList : function(id) {

              if (!this.isInList(id))
                      this._list.push(id);
      },
/*
* removeFromList - remove a id from the list
*
* @param id - sys_id to remove
* @return - NA
* @uses - this._list
*
*/
      removeFromList : function(id) {

              var index = this._getIndex(id);

              if (index > -1)
                      this._list.splice(index, 1);
      },

/*
* getList - display the list as CSV
*
* @param - NA
* @return - string of CSV
* @uses - this._list
*
*/
      getList : function() {

              return this._list.join(',');
      },

/*
* _getIndex - return the index of an element in list
*
* @param id - id to look for
* @return - position of id in list (0..n/-1 = not found)
* @uses - this._list
*
*/
      _getIndex : function(id) {

              for (var i = 0; i < this._list.length; i++) {

                      if (this._list[i] == id)
                              return i;
              }

              return -1;
      },

/*
* _debug - print a message to the debug log
*
* @param s - string to print
* @return - NA
* @usrs - this._debug
*
*/
      _debug : function(s) {

              if (this.debug)
                      gs.print('>>>DEBUG: ListUtil: ' + s);
      },

      type: 'ListUtil'
}

Here's an sample script that demonstrates the various functions:

var inc = '04b28ae2c0a8016600c8f3d86e3278f4'; // INC0000066
var usr1 = '46d44a23a9fe19810012d100cca80666'; // Beth Anglin
var usr2 = '5137153cc611227c000bbd1bd8cd2005'; // Fred Luddy
var usr3 = '62826bf03710200044e0bfc8bcbe5df1'; // Abel Tuter
var gr = new GlideRecord('incident');

if (!gr.get(inc)) {
      gs.print('Error reading record.');

} else {
      var lu = new ListUtil(gr.watch_list);

      gs.print('Fred is in the list: ' + lu.isInList(usr2));

      lu.removeFromList(usr2); // Take Fred out of the list
      gs.print('Removed Fred: list=' + lu.getList());

      lu.addToList(usr3); // Add Abel to the list
      gs.print('Added Abel: list=' + lu.getList());

      lu.addToList(usr2); // add Fred back in
      lu.addToList(usr3); // add Abel (again)
      gs.print('Final: list=' + lu.getList());

      // Save the current list to the record and update
      gr.watch_list = lu.getList();
      gr.update();
}