ICustomOperator Interface
Interface for a custom operator.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CECustomObjects assembly)
Syntax
public interface ICustomOperatorRemarks
A custom operator is an object written by an application developer that extends the Carmenta Engine functionality when some non-standard feature is required. The custom operator is just a regular class that can be written in C++, Java, or any Microsoft .NET language like C#, that implements the ICustomOperator interface.
The custom operator can be used directly in a map configuration using a CustomOperatorProxy object. The proxy works as regular Carmenta Engine operator, but delegates most calls to the custom object. Please see CustomOperatorProxy for more information how to configure and load the custom object.
The ICustomOperator interface contains four methods, InitNew, Prepare, Get and Clone. As described in the documentation of Operator, features flow through operators during an update of a view and its layers. The update starts with a call to Prepare followed by a sequence of calls to Get until no more features are returned.
Exceptions that are thrown by custom object implementations will be logged and then propagated by Carmenta Engine as an EngineException to the application. Also, the only way a C++ custom object implementation can include a relevant error message to an application is by throwing an EngineException.
Optimizing the performance of .NET and Java custom objects
Custom objects that are implemented in .NET or Java, both of which use a garbage collector to manage memory, can generate a lot of temporary object instances that must be collected and finalized by the garbage collector. These temporary objects can, depending on how many times a custom object is called during a typical update cycle, generate so much extra work for the garbage collector that it has a significant impact on performance.
In many cases you can improve the performance by adding the IMinimizeGarbageCollection interface to the custom operator implementation. This tells Carmenta Engine that reference objects passed to, and returned from, the custom object should be disposed automatically which decreases the work that must be performed by the garbage collector.
Platforms
Windows, Linux, Android
See Also
Reference
CustomObjects Module
CustomOperatorProxy
ICustomDataSet
ICustomVisualizer
ICustomSymbol
ICustomPropagation
IMinimizeGarbageCollection
ICustomOperator Members
The ICustomOperator type has the following members.
Methods
| Name | Description |
|---|---|
| Clone | Called to create a copy of the custom object. |
| Get | Gets the next feature. |
| InitNew | Called when the custom operator is created by or connected to a CustomOperatorProxy. |
| Prepare | Prepares the operator for an update cycle. |