java.lang.Object
- org.epics.archiverappliance.engine.pv.EngineContext

```
public class EngineContext
extends Object
```
the context for the Archiver Engine

Author:

Luofeng Li

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`class`	`EngineContext.CommandThreadChannel`	Go thru all the contexts and return channels whose names match this This is to be used for for testing purposes only.

Constructor Summary

Constructors
Constructor Description

EngineContext(ConfigService configService)
This EngineContext should always be singleton

Method Summary

Modifier and Type	Method	Description
`boolean`	`abortComputeMetaInfo(String pvName)`
`int`	`assignJCACommandThread(String pvName, String iocHostName)`	Use this to assign JCA command threads to PV's
`void`	`computeMetaInfo(PubSubEvent pubSubEvent)`
`boolean`	`doesContextMatchThread(gov.aps.jca.Context context, int jcaCommandThreadId)`
`List<EngineContext.CommandThreadChannel>`	`getAllChannelsForPV(String pvName)`
`double`	`getAverageSecondsConsumedByWriter()`
`int`	`getCAJChannelCount()`	Get the total channel count as CAJ sees it.
`List<Map<String,String>>`	`getCAJContextDetails()`	Return some details on the CAJ contexts for the metrics page.
`ConcurrentHashMap<String,ArchiveChannel>`	`getChannelList()`
`org.epics.pvaccess.client.ChannelProvider`	`getChannelProvider()`
`ConcurrentHashMap<String,ControllingPV>`	`getControlingPVList()`
`JCACommandThread`	`getJCACommandThread(int jcaCommandThreadId)`
`int`	`getMainSchedulerPendingTasks()`	Get the number of tasks pending in the main scheduler.
`ScheduledThreadPoolExecutor`	`getMiscTasksScheduler()`
`double`	`getSampleBufferCapacityAdjustment()`	Per FRIB/PSI, we have a configuration knob to increase/decrease the sample buffer size used by the engine for all PV's.
`ScheduledThreadPoolExecutor`	`getScanScheduler()`	Get the scheduler used for SCAN PV's
`ScheduledThreadPoolExecutor`	`getScheduler()`
`double`	`getWritePeriod()`
`WriterRunnable`	`getWriteThead()`
`boolean`	`isWriteThreadStarted()`
`void`	`setDisconnectCheckTimeoutInMinutesForTestingPurposesOnly(int newDisconnectCheckTimeoutMins)`
`void`	`setSecondsConsumedByWriter(double secondsConsumedByWriter)`	set the time consumed by writer to write the sample buffer once
`void`	`startWriteThread(ConfigService configservice)`	start the write thread of the engine and this is actually called by the first pv when creating channel

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - EngineContext
```
public EngineContext(ConfigService configService)
```
    This EngineContext should always be singleton
    
    Parameters:
    
    configService - the config service to initialize the engine context
- Method Detail
  - getControlingPVList
```
public ConcurrentHashMap<String,ControllingPV> getControlingPVList()
```
    Returns:
    
    the list of pvs controlling other pvs
  - setSecondsConsumedByWriter
```
public void setSecondsConsumedByWriter(double secondsConsumedByWriter)
```
    set the time consumed by writer to write the sample buffer once
    
    Parameters:
    
    secondsConsumedByWriter - the time in second consumed by writer to write the sample buffer once
  - getAverageSecondsConsumedByWriter
```
public double getAverageSecondsConsumedByWriter()
```
    Returns:
    
    the average time in second consumed by writer
  - getJCACommandThread
```
public JCACommandThread getJCACommandThread(int jcaCommandThreadId)
```
  - assignJCACommandThread
```
public int assignJCACommandThread(String pvName,
                                  String iocHostName)
```
    Use this to assign JCA command threads to PV's
    
    Parameters:
    
    pvName - The name of PV
    
    iocHostName - Note this can and will often be null.
    
    Returns:
    
    threadId
  - doesContextMatchThread
```
public boolean doesContextMatchThread(gov.aps.jca.Context context,
                                      int jcaCommandThreadId)
```
  - getChannelList
```
public ConcurrentHashMap<String,ArchiveChannel> getChannelList()
```
    Returns:
    
    the channel list of pvs, without the pvs for meta fields
  - getScheduler
```
public ScheduledThreadPoolExecutor getScheduler()
```
    Returns:
    
    the scheduler for the whole engine
  - getScanScheduler
```
public ScheduledThreadPoolExecutor getScanScheduler()
```
    Get the scheduler used for SCAN PV's
    
    Returns:
    
    scanScheduler
  - getWriteThead
```
public WriterRunnable getWriteThead()
```
    Returns:
    
    the WriterRunnable for the engines
  - startWriteThread
```
public void startWriteThread(ConfigService configservice)
```
    start the write thread of the engine and this is actually called by the first pv when creating channel
    
    Parameters:
    
    configservice - configservice used by this writer
  - getWritePeriod
```
public double getWritePeriod()
```
    Returns:
    
    the writing period in second
  - isWriteThreadStarted
```
public boolean isWriteThreadStarted()
```
    Returns:
    
    the status of the writing thread. return true, if it is started.Otherwise, return false;
  - computeMetaInfo
```
public void computeMetaInfo(PubSubEvent pubSubEvent)
```
  - abortComputeMetaInfo
```
public boolean abortComputeMetaInfo(String pvName)
```
  - setDisconnectCheckTimeoutInMinutesForTestingPurposesOnly
```
public void setDisconnectCheckTimeoutInMinutesForTestingPurposesOnly(int newDisconnectCheckTimeoutMins)
```
    Parameters:
    
    newDisconnectCheckTimeoutMins - This is to be used only for unit testing purposes... There are no guarantees that using this on a running server will be benign.
  - getAllChannelsForPV
```
public List<EngineContext.CommandThreadChannel> getAllChannelsForPV(String pvName)
```
  - getSampleBufferCapacityAdjustment
```
public double getSampleBufferCapacityAdjustment()
```
    Per FRIB/PSI, we have a configuration knob to increase/decrease the sample buffer size used by the engine for all PV's. This comes from archappl.properties and is a double - by default 1.0 which means we leave the buffer size computation as is. If you want to increase buffer size globally to 150% of what is normally computed, set this to 1.5
    
    Returns:
    
    sampleBufferCapacityAdjustment
  - getCAJChannelCount
```
public int getCAJChannelCount()
```
    Get the total channel count as CAJ sees it.
    
    Returns:
    
    totalCAJChannelCount
  - getChannelProvider
```
public org.epics.pvaccess.client.ChannelProvider getChannelProvider()
```
  - getMiscTasksScheduler
```
public ScheduledThreadPoolExecutor getMiscTasksScheduler()
```
  - getMainSchedulerPendingTasks
```
public int getMainSchedulerPendingTasks()
```
    Get the number of tasks pending in the main scheduler. This is the one that powers the write thread.
    
    Returns:
  - getCAJContextDetails
```
public List<Map<String,String>> getCAJContextDetails()
```
    Return some details on the CAJ contexts for the metrics page.
    
    Returns:

Class EngineContext

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

EngineContext

Method Detail

getControlingPVList

setSecondsConsumedByWriter

getAverageSecondsConsumedByWriter

getJCACommandThread

assignJCACommandThread

doesContextMatchThread

getChannelList

getScheduler

getScanScheduler

getWriteThead

startWriteThread

getWritePeriod

isWriteThreadStarted

computeMetaInfo

abortComputeMetaInfo

setDisconnectCheckTimeoutInMinutesForTestingPurposesOnly

getAllChannelsForPV

getSampleBufferCapacityAdjustment

getCAJChannelCount

getChannelProvider

getMiscTasksScheduler

getMainSchedulerPendingTasks

getCAJContextDetails