org.lsst.ccs.subsystem.ocsbridge.util

Class State<T extends Enum>

java.lang.Object

org.lsst.ccs.subsystem.ocsbridge.util.State<T>

Type Parameters:

T - The enumeration representing the states.

public class State<T extends Enum>
extends Object

Encapsulates a state, and generates state change events.

This class is thread-safe, its methods can be called on any thread. Listeners are guaranteed to be notified sequentially. For every listener, the order of notifications corresponds to the order of state changes. However, the internal state of this State instance is not guaranteed to remain unchanged by the the time listeners are notified.

The internal state of this State instance is protected by its monitor lock. The way to extract multiple state parameters (value and cause) is to call corresponding getters while holding this lock.

Author:

tonyj

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	State.InvalidStateException
static interface	State.StateChangeListener<T extends Enum>

Constructor Summary

Constructors

Constructor and Description
State(T initialState) Create a new state

Method Summary

Modifier and Type	Method and Description
void	addStateChangeListener(State.StateChangeListener<T> listener)
void	checkState(T... states) Check the state and generate an exception if the current state does not match.
String	getCause()
Class<T>	getEnumClass()
T	getState()
boolean	isInState(T state)
void	removeStateChangeListener(State.StateChangeListener<T> listener)
void	setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when, State<T> state)
void	setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when, T state)
void	setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when, T state, String cause)
void	setState(T state) Changes the current state.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

State

public State(T initialState)

Create a new state

Parameters:

initialState - Initial state

Method Detail

setState

public void setState(T state)

Changes the current state. Generates a status change notification when the status is changed.

Parameters:

state - The new state

setState

public void setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when,
                     T state)

setState

public void setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when,
                     State<T> state)

setState

public void setState(org.lsst.ccs.utilities.taitime.CCSTimeStamp when,
                     T state,
                     String cause)

getState

public T getState()

getCause

public String getCause()

getEnumClass

public Class<T> getEnumClass()

isInState

public boolean isInState(T state)

addStateChangeListener

public void addStateChangeListener(State.StateChangeListener<T> listener)

removeStateChangeListener

public void removeStateChangeListener(State.StateChangeListener<T> listener)

checkState

public void checkState(T... states)
                throws State.InvalidStateException

Check the state and generate an exception if the current state does not match.

Parameters:

states - The expected state, may be a list of possible states

Throws:

State.InvalidStateException - If the state does not match.

toString

public String toString()

Overrides:

toString in class Object