Creating the Data Utility Class
Create your data utility by implementing the com.ptc.core.components.descriptor.DataUtility interface.
Since data utilities are looked up using application context, your implementation class must be public and must have a public no-arg constructor.
It is highly recommended that when you implement a new data utility, you extend the AbstractDataUtility base class.
If you have a need to augment the attribute value or change how the attribute is rendered, you should consider extending the existing data utility, if applicable. Use the Available Attributes Report or JcaDebug to find the data utility currently mapped to an attribute. See
Available Attributes Report and
Using jcaDebug for more information.
1. Implement the getDataValue() method of the DataUtility interface:
The getDataValue() method gets the content that should be placed in the UI for a given attribute.
Example:
Suppose you want to append the value of a specific string attribute with some extra text. This can be done as follows:
Object getDataValue(String component_id, Object datum, ModelContext mc)
throws WTException {
…..
…..
String rawVal = myObject.get(component_id);
String displayVal = rawVal + “My extra text”;
TextDisplayComponent gui = new TextDisplayComponent(…);
gui.setValue(displayVal);
…
…
return gui;
}
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Avoid making database calls in getDataValue(), because when dealing with tables, the method is called once for every cell in the column. If they must be done, try to do work in setModelData() which is called once per column and cache the results so the database does not have to be called more often than necessary.
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2. Implement the setModelData() method of the DataUtility interface:
In the interests of performance, we want to process all the objects to be displayed in a single call to setModelData() and to perform the required database queries for all the objects at once, rather than making a separate query for each object.
When multiple objects needs to be fetched, as in the case of a table where multiple row objects needs to be fetched, the setModelData()method allows the data utility to prefetch data for all the row objects that will be rendered. The method is called before getDataValue()is called for any row/cell, and is supplied a list of all the objects that will be processed.
You can take advantage of this call to do some multi-object queries and save the results for later use in the getDataValue() method. If this method is implemented, then you must configure the data utility to be stateful.
