Package fr.esrf.tangoatk.core

This package contains the model part of TangoATK.

See:
Description

Interface Summary

IAttribute	IAttribute is the top interface for all attributes.
IAttributeScalarHistory
IAttributeStateListener
IBooleanImage
IBooleanImageListener
IBooleanScalar
IBooleanScalarListener
IBooleanSpectrum
IBooleanSpectrumListener
ICommand	ICommand is the interface that defines a command.
ICommandGroup	ICommandGroup is the interface that defines a commandGroup.
IDevice
IDeviceApplication
IDeviceListener
IDevStateScalar
IDevStateScalarListener
IDevStateSpectrum
IDevStateSpectrumListener
IEndGroupExecutionListener	IEndGroupExecutionListener defines the behaviour of an object that listens to the end of the execution of a group of commands.
IEntity	IEntity is the basic, uh, entity in TangoATK.
IEntityCollection
IEntityFilter	IEntityFilter
IEntityList
IEnumScalar
IEnumScalarListener
IErrorHandler
IErrorListener
IFactory
IImageListener
ILogListener
INumber
INumberImage
INumberScalar
INumberScalarHistory
INumberScalarListener
INumberSpectrum
IRawImage
IRawImageListener
IRefreshee	The interface IRefreshee has one method IRefreshee.refresh() which is called by someone whenever it is time for the refreshee to refresh its listeners.
IRefresherListener	The interface IRefresherListener has one method IRefresherListener.refreshStep() which is called by the refresher after all models belonging to a list are updated.
IResultListener	IResultListener defines the behaviour of an object that listens to results from commands.
IScalarAttribute
ISetErrorListener
ISpectrumListener
IStateListener
IStatusListener
IString
IStringImage
IStringImageListener
IStringScalar
IStringScalarHistory
IStringScalarListener
IStringSpectrum
IStringSpectrumListener

Class Summary

AEntityFactory	AEntityFactory keeps all the code that is common for the AttributeFactory and the CommandFactory.
AEntityList
AEntityProperty
ATKEvent
AtkEventListenerList	A class to handle AtkEventList.
AttributeList
AttributePolledList	A class to force the usage of client side polling (ATK refreshser) (Ingore events)
AttributeStateEvent
BooleanImageEvent
BooleanScalarEvent
BooleanSpectrumEvent
CommandGroup	The CommandGroup contains only the commands with no input and no output argument : they are all "VoidVoidCommand"s.
CommandList	The CommandList keeps all the commands we're working with.
Device	An object that maps to a Tango Device.
DeviceFactory
DeviceItem
DeviceProperty	DeviceProperty is a class which is responsible for holding information about a given property of a given Device.
DevStateScalarEvent
DevStateSpectrumEvent
DisplayLevelProperty
EndGroupExecutionEvent
EnumScalarEvent
ErrorEvent
ErrorHandlerAdapter
EventSupport	EventSupport handles the event-generating of the core part in ATK.
FormatProperty
NumberImageEvent
NumberProperty
NumberScalarEvent
NumberSpectrumEvent
Property	Property is a class which responsible for holding information about a given Property of a given IEntity.
PropertyStorage
RawImageEvent
Refresher	ARefresher is used as a base class to implement refreshers of IRefreshees.
ResultEvent
StateEvent
StatusEvent
StringImageEvent
StringProperty
StringScalarEvent
StringSpectrumEvent
TypeProperty
WritableProperty

Exception Summary

ATKException	A base class to handle error in ATK.
AttributeReadException
AttributeSetException
CommandExecuteException
ConnectionException
DeviceException

Package fr.esrf.tangoatk.core Description

This package contains the model part of TangoATK. Core has no knowledge of its viewers, core only knows how to send events to its listeners.
Most users will only need to access

• AttributeList
• CommandList
• DeviceFactory

to get things started.

Overview

Most of the code in this package is written to facilitate the handling of Attributes and Commands. Normally, users of this package should not try to instanciate attributes and commands by themselves, but rather use the AttributeList and the CommandList respectively. For more finegrained control, a CommandFactory and an AttributeFactory is provided.

Communication model

The communication model of TangoATK is based on the model used by java-beans, that is, objects register themselves as listeners to other object's events. All the listener-interfaces in core are derived from IErrorListener, so that all listeners are forced to implement some kind of errorhandling.

Properties

Both commands and attributes have properties attached to them. Some properties are common to both commands and attributes, and thus the hierarchy of classes representing the properties work with both commands and properties.

There are two ways of obtaining properties from a command or attribute. Either by calling getPropertyMap() which returns a java.util.Map with all propeties, or by calling specialized methods in the objects, such as getName() which returns the value for a particular property.

Overview of the attribute hierarchy

The Attributes in TangoATK come in different flavors. As an abstraction over Tango, all numeric types are coerced into doubles, and there exists no String types for images, which leaves us with:

• NumberImage, represented by the interface INumberImage
• NumberSpectrum, represented by the interface INumberSpectrum
• NumberScalar, represented by the interface INumberScalar
• StringScalar, represented by the intervace IStringScalar
• StringSpectrum, represented by the intervace IStringSpectrum
• DevStateScalar, represented by the interface IDevStateScalar
• BooleanScalar, represented by the interface IBooleanScalar
• BooleanSpectrum, represented by the interface IBooleanSpectrum
• BooleanImage, represented by the interface IBooleanImage

All of the interfaces inherit from IAttribute, which is the interface that defines an attribute.

Overview of the command hierarchy

Commands are defined by the ICommand inteface, and implemented in the classes:

• VoidVoidCommand
• VoidScalarCommand
• VoidArrayCommand
• ScalarVoidCommand
• BooleanVoidCommand
• StringVoidCommand
• ScalarScalarCommand
• ScalarArrayCommand
• ArrayVoidCommand
• ArrayScalarCommand
• ArrayArrayCommand

To interpret these names, the type of the input parameter is given as the first part of the class name, the type of the output parameter is given as the second part of the class name.
So a command which is of type ScalarArrayCommand takes a scalar value as input and returns an array as output.

How to obtain the results of a command

As with everything else in TangoATK, the commands also work with events, that is, every time a command is executed, it sends out a ResultEvent to all its listeners with the result of the command.

The Finer points of commands

To make life easier for the programmer, all types commands accept a java.util.List as input. A command which doesn't take any input will silently ignore the input, a command which takes a scalar as input will use only the first value in the list. Array command will parse the list as best it can.

Regarding input, a command will accept any input to any command, there are no compiletime checks to make sure a string is not passed to a command accepting a double allthough this error will be caught at runtime.