Package org.scictrl.csshell.epics.server.processor

Class OnDemandValueProcessor

java.lang.Object

org.scictrl.csshell.epics.server.processor.AbstractValueProcessor

org.scictrl.csshell.epics.server.processor.OnDemandValueProcessor

All Implemented Interfaces:

ValueProcessor

public class OnDemandValueProcessor
extends AbstractValueProcessor

OnDemandValueProcessor class.

Author:

igor@scictrl.com

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	OnDemandValueProcessor.ValueProvider	An interface which is asked each time new value is needed.

Field Summary

Fields inherited from class org.scictrl.csshell.epics.server.processor.AbstractValueProcessor

log, record, trigger, type

Constructor Summary

Constructors

Constructor	Description
OnDemandValueProcessor()	Constructor.

Method Summary

Modifier and Type	Method	Description
gov.aps.jca.dbr.TimeStamp	getTimestamp()	Timestamp indicates last time value has been updated or confirmed.
Object	getValue()	getValue.
static final OnDemandValueProcessor	newProcessor(String name, gov.aps.jca.dbr.DBRType type, int count, String description)	newProcessor.
void	reset()	Resets cached value to null.
void	setKey(Object key)	The key which is associated with this processor and help provider distinguish between different processors.
void	setProvider(OnDemandValueProcessor.ValueProvider provider)	Sets new provider object.
void	setValue(Object value)	Sets new value to the processor.

Methods inherited from class org.scictrl.csshell.epics.server.processor.AbstractValueProcessor

activate, configure, getName, getRecord, getTrigger, getType, process, toString

Methods inherited from class java.lang.Object

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

Constructor Details

OnDemandValueProcessor

public OnDemandValueProcessor()

Constructor.

Method Details

newProcessor

public static final OnDemandValueProcessor newProcessor(String name,
 gov.aps.jca.dbr.DBRType type,
 int count,
 String description)

newProcessor.

Parameters:

name - a String object

type - a DBRType object

count - a int

description - a String object

Returns:

a OnDemandValueProcessor object

setProvider

public void setProvider(OnDemandValueProcessor.ValueProvider provider)

Sets new provider object. Provider is asked for new value when necessary.

Parameters:

provider - the on-demand value provided

setKey

public void setKey(Object key)

The key which is associated with this processor and help provider distinguish between different processors.

Parameters:

key - the unique key

setValue

public void setValue(Object value)

Sets new value to the processor. If value is different from current processor value, then event is fired. Timestamp is updated regardless if value is changed, since timestamp indicates last value update or confirmation. Does absolutly nothing, vbalue is oabtained trough provider.

Parameters:

value - a Object object

See Also:

• ValueProcessor.setValue(java.lang.Object)

getValue

public Object getValue()

getValue.

Each time EPICS server is asked for value this method is called. If this processor has value in cache, the value from cache is returned. If cached value is null (or it was never set or processor was reset), then the provider is asked for new value.

Returns:

a Object object

See Also:

• ValueProcessor.getValue()

getTimestamp

public gov.aps.jca.dbr.TimeStamp getTimestamp()

Timestamp indicates last time value has been updated or confirmed. This does not necessary means value change. Timestamp of last time provider was asked for value.

Returns:

a TimeStamp object

See Also:

• ValueProcessor.getTimestamp()

reset

public void reset()

Resets cached value to null. So when next time getValue request will come, a new value will be requested from provider.