Difference between revisions of "Scout/Concepts/LookupCall"

Revision as of 09:56, 2 November 2011

Lookup calls are mainly used by SmartFields and SmartColumns to look up single or multiple LookupRows.

• Class: LookupCall

Description

The Lookup call mechanism is used to lookup up a set of key-text pairs. Whereas the key can be of any Java type the text must be of the type String. Each entry in this set is called LookupRow. In addition to the key and the text a LookupRow can also define and icon, font, colors and a tooltiptext.

This schema explains the role of a LookupCall in a SmartField:

Input

Lookup calls provide different method to compute the set of LookupRows :

• getDataByKey(): Retrieves a single lookup row for a specific key value. Used by SmartFields and SmatColumns to get the display text for a given key value.
• getDataByText(): Retrieve multiple lookup rows which match a certain String. Used by SmartFields when the user starts to enter some text in the field.
• getDataByAll(): Retrieves all available lookup rows. Used by SmartFields when the user clicks on the browse icon.
• getDataByRec(): This can only be used for hierarchical lookup calls. It retrieves all available sub-tree lookup rows for a given parent.

TODO
parameters are present to compute the set of rows: Object key, ... Master

Type of lookup calls

With a Lookup Service

Delegation to the Lookup Service on server side.

They are not necessarily restricted to a fix number of records. Instead they should be favoured if the set of records is rather large.

Directy

Principe of the Local Lookup Calls

TODO
Explain and mention the execCreateLookupRows method

An example of this approach is when a SmartField or a SmartColumn is configured to be use with a CodeType. A CodeLookupCall is instantiated for the CodeType. It creates the LookupRows corresponding to the codes in the CodeType.

Overview

Properties

Defined with getConfiguredXxxxxx() methods.

• Service: Defines which service is used to retrieve lookup rows
• MasterRequired: Defines whether a master value must be set in order to query for multiple lookup rows

Code example

Using a LookupCall in a SmartField

public class ColorSmartField extends AbstractSmartField<String> {
  // other configuration of properties.
  @Override
  protected Class<? extends LookupCall<?>> getConfiguredLookupCall(){
    return ColorLookupCall.class;
  }
}

Accessing a LookupRow directly

It is possible to access a LookupRow direclty. In this example the input is a key (thisKey) and the method getDataByKey() is used. Before accessing the text, we ensure that a LookupRow has been retrived.

//Execute the LookupCall (using DataByKey)
LookupCall call = new MyLookupCall();
call.setKey(thisKey);
LookupRow[] rows=call.getDataByKey();
 
//Get the text (with a null check)
String text = null;
if(rows != null && rows.length > 0) {
  text = rows[0].getText();
}

See Also

• Lookup Row
• Lookup Service
• Local Lookup Calls
• Shared Plug-In