Routed Systems Designer
=======================

Example Java Classes
=======================
February 2003


1	Using the Java classes
	======================

The description about how the classes are loaded and called is given in the Routed Systems Designer 
Manual, under the section: About the Java User Interface Extension.

2	Classes and methods
	===================

Class CheckConnection 
       implements rsdesigner.uiextension.Connection
Methods:
	canConnectBetween
	postConnect

Class ExampleValidateProperties 
       implements rsdesigner.uiextension.ValidateProperties
Methods:
	canSet

Class ExampleUpdateProperties
	implements rsdesigner.uiextension.UpdateProperties
Methods:
	update
	
3	Class descriptions
	==================

3.1	Class CheckConnection
	=====================

This class provides methods to check two situations: firstly whether connections can be made between (or 
to) objects and also to set extra properties when a connection has been made. 

The canConnectBetween method is used to check whether a connection can be made between two objects. 
It returns a Boolean, where true means that the connection is allowed. The canConnectBetween method in 
the supplied example will check to see if the FibreShape that is being used to connect the Shapes has the 
name Purple_Wire. If it does then the example will only allow connection between the shapes if it the date 
is such that the moon is new.

The postConnect method is used to modify the properties of objects that are connected (either using a fiber 
or direct connections between components). The postConnect method in the supplied example will check 
set the max_current property of the fiber that connects two components. The value of max_current will be 
the maximum of the max_current properties on the components. It is possible that neither of the 
components have the property max_current, in which case the getValue call for each will return 0.0, in 
which case the max_current property will not be set.

3.2	Class ExampleValidateProperties
	===============================

This class provides the method canSet and is used to determine if a set of properties can be applied to a 
newly created Artifact. The example in the ExampleValidateProperties class will first list the set of 
properties that are to be set, along with their type and value. It will subsequently perform an example 
check: if the object to be created is a fiber then the example will check that the fiber is of type 
CONNECTION!WIRE!WIRING_WIRE and the property min_bend_radius is set. If the supplied 
min_bend_radius is less that 2.0 then the method returns false, with the message "Cannot set this 
min_bend_radius". The method returns a Boolean, if the returned value is false then a message explaining 
why the validation failed can be included by using properties.setMessage.

3.3	Class ExampleUpdateProperties
	=============================

This class provides the method update that allows the setting of properties on an Artifact after it has been 
created. It is useful for adding extra properties, such as a timestamp of when the object was created, or who 
created it. The example method checks whether the newly-created component has a property category and, 
if so, whether its value is "lamps". If that is the case the method adds the properties model (with value 
"softone") and description (with value "flashing monochrome"). This method demonstrates the techniques 
for querying the Properties class