JCACommandThread

java.lang.Object
- java.lang.Thread
- - org.epics.archiverappliance.engine.pv.JCACommandThread

All Implemented Interfaces:

Runnable
```
public class JCACommandThread
extends Thread
```
JCA command pump, added for two reasons:
1. JCA callbacks can't directly send JCA commands without danger of a deadlock, at least not with JNI and the "DirectRequestDispatcher".
2. Instead of calling 'flushIO' after each command, this thread allows for a few requests to queue up, then periodically pumps them out with only a final 'flush'
Version:

Initial version:CSS, 4-Jun-2012, Luofeng Li:added codes to support for the new archiver

Author:

Kay Kasemir

Nested Class Summary
- Nested classes/interfaces inherited from class java.lang.Thread
  Thread.State, Thread.UncaughtExceptionHandler

Field Summary
- Fields inherited from class java.lang.Thread
  MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors
Constructor Description

JCACommandThread(ConfigService configService)
Construct, but don't start the thread.

Method Summary

Modifier and Type	Method	Description
`void`	`addCommand(Runnable command)`	Add a command to the queue.
`void`	`run()`
`void`	`shutdown()`	Stop the thread and wait for it to finish
`void`	`start()`	Version of `start` that may be called multiple times.

Methods inherited from class java.lang.Thread
activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, stop, suspend, toString, yield

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

- Constructor Detail
  - JCACommandThread
```
public JCACommandThread(ConfigService configService)
```
    Construct, but don't start the thread.
    
    Parameters:
    
    configService - ConfigService
    
    See Also:
    
    start()
- Method Detail
  - start
```
public void start()
```
    Version of start that may be called multiple times.
    The thread must only be started after the first PV has been created. Otherwise, if flush is called without PVs, JNI JCA reports pthread errors.
    NOP when already running
    
    Overrides:
    
    start in class Thread
  - shutdown
```
public void shutdown()
              throws InterruptedException
```
    Stop the thread and wait for it to finish
    
    Throws:
    
    InterruptedException -
  - addCommand
```
public void addCommand(Runnable command)
```
    Add a command to the queue. add some cap on the command queue? At least for value updates?
    
    Parameters:
    
    command - Runnable
  - run
```
public void run()
```
    Specified by:
    
    run in interface Runnable
    
    Overrides:
    
    run in class Thread