Want to have accurate filtered dropdown lists on your dialog boxes?

You have probably invested a large amount of time and effort in building the taxonomy describing the relationships that exist within your company. Using the CIS API you can use this established and accurate taxonomy to create filtered drop down lists in your applications. This ensures that your application’s drop down lists always have the correct values.

Querying the Taxonomy in Real-Time

For example, let us assume that the taxonomy contains the following hierarchy. You can use the CIS API to walk the tree and populate dropdowns such that when the user selects 'Tissue and Cell Preparation' from the first box they get 'Freeze Etching, Freeze Substitution, Sectioning and Staining', then when they pick 'Staining' they get 'Horseradish Peroxidase, etc''

Tissue and Cell Preparation Freeze Etching Freeze Substitution Sectioning Staining Horseradish Peroxidase Immunocytochemistry Ferritin Labeling Immunoelectron Microscopy Immunofluorescence Technique Immunoperoxidase Silver Impregnation

Like walking any hierarchical tree the following steps should be taken;

1. Find the top-level nodes and use them to populate the top level drop-down list.
2. When the user selects a value, find the children of that node and populate the next drop-down.
3. If the user selects another value, go to Step 2 and repeat the process

Obviously doing this in real time would be inefficient so the values would probably be cached locally, this code illustrates how to read in those values.

Retrieving top-level taxonomy nodes

This example shows how you can retrieve all of the top-level taxonomy nodes from the system. This includes sorting all of the nodes by their label.

Note: oSession is a valid remote, lightweight, or heavyweight session object, as described in Chapter 3 of the Initializing Business Intelligence Services available from the Developer Program website.

	  oRdSvc = RdService.access(oSession);
	  TaxonomyNodeMgr oMgr = oRdSvc.newTaxonomyNodeMgr();
	  ITaxonomyNode oTaxNode = oMgr.newEntity();

	  oMgr.filterByParentNodeId(0);
	  oMgr.sortByLabel(false);

	  for (boolean fResult = oMgr.first(oTaxNode);
           fResult;
           fResult = oMgr.next(oTaxNode))

	  {
	    // Here you can, for example, populate your top level drop down list
	    System.out.println(oTaxNode.getLabel());
	  }

	  oMgr.flush();
	  oMgr.resetFilters();

Once you have the root node of a taxonomy (that is, one of the nodes you found using this procedure), you can find that node’s subnodes by specifying the root node’s ID as the parent ID when calling filterByParentNodeId().

Retrieving subnodes of a taxonomy node

The procedure for retrieving subnodes of a given node differs from the procedure to find top-level taxonomy nodes in only one step. When you specify the parent node ID in the call to filterByParentNodeId(), you specify the node for which you wish to find the subnodes, instead of 0. This example shows how you can retrieve all of the subnodes for a given node. This example assumes two valid objects already exist:

	oRdSvc = RdService.access(oSession);
	TaxonomyNodeMgr oMgr = oRdSvc.newTaxonomyNodeMgr();
	ITaxonomyNode oTaxNode = oMgr.newEntity();

	// Instead of 0, use the ID of the parent node
	oMgr.filterByParentNodeId(oParentNode.getId());
	oMgr.sortByLabel(false);

	for(boolean fResult =      oMgr.first(oTaxNode);
	    fResult;
	    fResult = oMgr.next(oTaxNode))
	{
	    // Here you can, for example, populate a drop down list
	    System.out.println(oTaxNode.getLabel());
	}

	oMgr.flush();
	oMgr.resetFilters();