com.aquenos.cassandra.pvarchiver.controlsystem

Class ControlSystemChannelStatus

java.lang.Object

com.aquenos.cassandra.pvarchiver.controlsystem.ControlSystemChannelStatus

public final class ControlSystemChannelStatus
extends Object

Status of a ControlSystemChannel. Instances of this class can be created through the connected(), disconnected(), and error(Throwable) methods.

Author:

Sebastian Marsching

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ControlSystemChannelStatus.State State of a control-system channel.

Method Summary

Modifier and Type	Method and Description
static ControlSystemChannelStatus	connected() Returns a status that indicates that the channel is connected.
static ControlSystemChannelStatus	disabled() Returns a status that indicates that archiving for the channel has been temporarily disabled.
static ControlSystemChannelStatus	disconnected() Returns a status that indicates that the channel is disconnected.
boolean	equals(Object obj)
static ControlSystemChannelStatus	error(Throwable error) Returns a status that indicates that the channel is in the error state.
Throwable	getError() Returns the error associated with the channel status.
ControlSystemChannelStatus.State	getState() Returns the channel's state.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

connected

public static ControlSystemChannelStatus connected()

Returns a status that indicates that the channel is connected. This means that it is operating normally and is receiving updates with value changes.

Returns:

channel status representing the connected state.

disabled

public static ControlSystemChannelStatus disabled()

Returns a status that indicates that archiving for the channel has been temporarily disabled. This means that the control-system support is operating correctly, but has decided that samples should currently not be archived. Typically, such a decision will be made based on a dynamic condition (e.g. a certain flag being set on the channel's server or the state of another channel).

Unlike a channel that has been disabled in its configuration, a channel that has been disabled by the control-system support can become active at any time without user intervention.

Returns:

channel status representing the disabled state.

disconnected

public static ControlSystemChannelStatus disconnected()

Returns a status that indicates that the channel is disconnected. This means that due to a temporary problem (e.g. the corresponding server being stopped), value updates for the channel can currently not be received. However, this situation will recover automatically when the underlying problem has been solved.

Returns:

channel status representing the disconnected state.

error

public static ControlSystemChannelStatus error(Throwable error)

Returns a status that indicates that the channel is in the error state. This means that a permanent problem prevents the channel from operating. For example, an invalid configuration parameter might result in such a problem. For temporary problems from which the channel can recover automatically, when they are fixed, the disconnected state should be preferred.

Parameters:

error - optional error associated with the problem. May be null.

Returns:

channel status representing the error state with the given cause (if specified).

getError

public Throwable getError()

Returns the error associated with the channel status. If this status does not represent the ControlSystemChannelStatus.State.ERROR state, this method always returns null. Even if the channel is in the error state, the error might object might be null.

Returns:

error causing the channel's error state or null if this information is not available.

getState

public ControlSystemChannelStatus.State getState()

Returns the channel's state. This method never returns null.

Returns:

channel state.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object