Package org.eclipse.scanning.sequencer.watchdog

Class ExpressionWatchdog

java.lang.Object

org.eclipse.scanning.sequencer.watchdog.AbstractWatchdog<ExpressionWatchdogModel>

org.eclipse.scanning.sequencer.watchdog.ExpressionWatchdog

All Implemented Interfaces:

EventListener, IDeviceWatchdog<ExpressionWatchdogModel>, IModelProvider<ExpressionWatchdogModel>, INameable, IPositionListener

public class ExpressionWatchdog
extends AbstractWatchdog<ExpressionWatchdogModel>
implements IPositionListener

Monitors an expression of scannables and if one of the values changes, reevaluates the expression.

Example XML configuration:

  <!-- We assume that beam is available if the ring current is above background level -->
  <!-- and the port shutter is open -->
  <bean id="beam_available_model" class="org.eclipse.scanning.api.device.models.ExpressionWatchdogModel">
      <property name="expression" value="ring_current >= 1.0 &amp;&amp; !portshutter.equalsIgnoreCase(&quot;Closed&quot;)"/>
      <property name="message" value="Beam has been lost"/>
  </bean>

  <bean id="beam_available_watchdog" class="org.eclipse.scanning.sequencer.watchdog.ExpressionWatchdog" init-method="activate">
      <property name="name" value="beam_available_watchdog" />
      <property name="model" ref="beam_available_model"/>
  </bean>
 

Field Summary

Fields inherited from class org.eclipse.scanning.sequencer.watchdog.AbstractWatchdog

active, controller, model

Constructor Summary

Constructors

Constructor	Description
ExpressionWatchdog()
ExpressionWatchdog(ExpressionWatchdogModel model)

Method Summary

Modifier and Type	Method	Description
IExpressionService	getExpressionService()
String	getId()	Watchdog id
boolean	isPausing()	Returns whether the watchdog is currently active in a scan and pausing that scan.
void	pointEnd(IPosition done)
void	positionChanged(PositionEvent evt)	Called on a thread when the position changes.
void	positionPerformed(PositionEvent evt)	Called after a given position in a scan has been performed.
void	setExpressionService(IExpressionService eservice)
static void	setTestExpressionService(ServerExpressionService eservice)
void	start(ScanBean bean, IPosition firstPosition)
void	start(org.osgi.service.component.ComponentContext context)
void	stop()

Methods inherited from class org.eclipse.scanning.sequencer.watchdog.AbstractWatchdog

activate, deactivate, getController, getModel, getName, getScannable, isActive, isEnabled, scanFinally, scanStarted, setController, setEnabled, setModel, setName

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.scanning.api.IModelProvider

updateModel

Methods inherited from interface org.eclipse.scanning.api.scan.event.IPositionListener

levelPerformed, positionMovePerformed, positionWillPerform

Constructor Details

ExpressionWatchdog

public ExpressionWatchdog()

ExpressionWatchdog

public ExpressionWatchdog(ExpressionWatchdogModel model)

Method Details

getId

public String getId()

Description copied from interface: IDeviceWatchdog

Watchdog id

Specified by:

getId in interface IDeviceWatchdog<ExpressionWatchdogModel>

Returns:

id

positionChanged

public void positionChanged(PositionEvent evt)

Called on a thread when the position changes.

Specified by:

positionChanged in interface IPositionListener

Parameters:

evt -

positionPerformed

public void positionPerformed(PositionEvent evt)

Description copied from interface: IPositionListener

Called after a given position in a scan has been performed.

Specified by:

positionPerformed in interface IPositionListener

Parameters:

evt -

start

public void start(ScanBean bean,
 IPosition firstPosition)
           throws ScanningException

Throws:

ScanningException

pointEnd

public void pointEnd(IPosition done)

stop

public void stop()

getExpressionService

public IExpressionService getExpressionService()

setExpressionService

public void setExpressionService(IExpressionService eservice)

setTestExpressionService

public static void setTestExpressionService(ServerExpressionService eservice)

start

public void start(org.osgi.service.component.ComponentContext context)

isPausing

public boolean isPausing()

Description copied from interface: IDeviceWatchdog

Returns whether the watchdog is currently active in a scan and pausing that scan.

Specified by:

isPausing in interface IDeviceWatchdog<ExpressionWatchdogModel>