Package org.lsst.ccs

This package deals with core classes for subsystems.

See: Description

Interface Summary

Interface	Description
CommandHelper.RunnableWithException	An interface similar to Runnable but which allows exceptions to be generated and handled.
ServiceLifecycle	Package protected extension of HasLifecycle It provides additional life cycle steps that should only be used by services.
StateChangeListener	An internal listener to state changes.

Class Summary

Class	Description
Agent	Minimal component able to communicate on the buses.
AgentPropertyPredicate	Deprecated use org.lsst.ccs.bus.data.AgentPropertyPredicate instead.
BootUtils	A collection of static utilities linked to boot operations.
CommandHelper	A class to make it easier to execute commands while correctly handling ACKS, NACKS, and exceptions.
ComponentConfigurationEnvironment	Utility class to provide access to the Configuration API for a given component.
ConfigurationService	Provides the Configuration API to the subsystem it stands for.
PersistencyService	This objects is responsible for keeping track of fields annotated with Persist and to write them into a local file at subsystem shutdown or at regular time intervals.
RaisedAlertBookkeeper	Thread-safe modifiable RaisedAlertSummary.
Subsystem	The base class for a CCS subsystem.

Exception Summary

Exception	Description
AlarmNotClearedException	While trying to return the subsystem to normal mode it appears that alarms have not been cleared.
CommandHelper.CommandFailedException	Exception thrown if the target of the action method throws an exception.
HardwareException	base class ofr Hardware Exception.
SignalsStillRunning	While trying to return to normal (ready) mode it appears that some SIGNAL (signal) command is still running.
SystemStateException	Base class for reporting subsystem state anomalies.

Package org.lsst.ccs Description

This package deals with core classes for subsystems.

The Subsystem class is the parent class for subsystems that operate on the buses:

• NodeModularSubsystem: this class is used for Modular ("worker") subsystems
• BusMaster: for "active" subsystems that invoke commands to be executed by other subsystems.

Subsystem's code uses codes defined in:

• the "buses" sub-project (in package org.lsst.ccs.bus (defines data to be used for exchange between subsystems)
• in the "command" sub-project (the structure of the data exchanged when dealing with commands)
• in "messaging-layer" definition (how to exchange data)
• in "utilities"

Subsystem has an inner class to define its state: org.lsst.ccs.Subsystem.State. This class combines different enums to define the state of the subsystem

• The Phase : describe the current phase of subsystem life (such as initialization, operational, closing,..)
• The Mode : expresses the context in which and action may take place (such as normal or engineering)
• The CommandState : (such as ready to accept any command or off)
• the AlertState : (such as warning, alarm or none).

A subsystem provides also a CurrentCommandContext object that can be queried by codes running in the context of this subsystem and want to be aware of the context in which they are invoked.

The execution of command should be aware of instances of InvocationListener that may veto the execution of a command.

Other classes deal with standard Exceptions.

Author:

bamade