ExecuteWatchdog (Apache Commons Exec 1.3 API)

java.lang.Object
- org.apache.commons.exec.ExecuteWatchdog

All Implemented Interfaces:

TimeoutObserver
```
public class ExecuteWatchdog
extends Object
implements TimeoutObserver
```
Destroys a process running for too long. For example:
```
 ExecuteWatchdog watchdog = new ExecuteWatchdog(30000);
 Executer exec = new Executer(myloghandler, watchdog);
 exec.setCommandLine(mycmdline);
 int exitvalue = exec.execute();
 if (Execute.isFailure(exitvalue) && watchdog.killedProcess()) {
     // it was killed on purpose by the watchdog
 }
 
```
When starting an asynchronous process than 'ExecuteWatchdog' is the keeper of the process handle. In some cases it is useful not to define a timeout (and pass 'INFINITE_TIMEOUT') and to kill the process explicitly using 'destroyProcess()'.
Please note that ExecuteWatchdog is processed asynchronously, e.g. it might be still attached to a process even after the DefaultExecutor.execute has returned.
Version:

$Id: ExecuteWatchdog.java 1612032 2014-07-20 06:30:44Z ggregory $

See Also:
Executor, Watchdog

Field Summary

Fields
Modifier and Type Field and Description

static long INFINITE_TIMEOUT
The marker for an infinite timeout

Fields
Modifier and Type	Field and Description
`static long`	`INFINITE_TIMEOUT` The marker for an infinite timeout

Constructor Summary

Constructors
Constructor and Description

ExecuteWatchdog(long timeout)
Creates a new watchdog with a given timeout.

Constructors
Constructor and Description
`ExecuteWatchdog(long timeout)` Creates a new watchdog with a given timeout.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`checkException()` This method will rethrow the exception that was possibly caught during the run of the process.
`protected void`	`cleanUp()` reset the monitor flag and the process.
`void`	`destroyProcess()` Destroys the running process manually.
`boolean`	`isWatching()` Indicates whether or not the watchdog is still monitoring the process.
`boolean`	`killedProcess()` Indicates whether the last process run was killed.
`void`	`start(Process processToMonitor)` Watches the given process and terminates it, if it runs for too long.
`void`	`stop()` Stops the watcher.
`void`	`timeoutOccured(Watchdog w)` Called after watchdog has finished.

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

- Field Detail
  - INFINITE_TIMEOUT
```
public static final long INFINITE_TIMEOUT
```
    The marker for an infinite timeout
    
    See Also:
    Constant Field Values
- Constructor Detail
  - ExecuteWatchdog
```
public ExecuteWatchdog(long timeout)
```
    Creates a new watchdog with a given timeout.
    
    Parameters:
    timeout - the timeout for the process in milliseconds. It must be greater than 0 or 'INFINITE_TIMEOUT'
- Method Detail
  - start
```
public void start(Process processToMonitor)
```
    Watches the given process and terminates it, if it runs for too long. All information from the previous run are reset.
    
    Parameters:
    processToMonitor - the process to monitor. It cannot be null
    
    Throws:
    
    IllegalStateException - if a process is still being monitored.
  - stop
```
public void stop()
```
    Stops the watcher. It will notify all threads possibly waiting on this object.
  - destroyProcess
```
public void destroyProcess()
```
    Destroys the running process manually.
  - timeoutOccured
```
public void timeoutOccured(Watchdog w)
```
    Called after watchdog has finished.
    
    Specified by:
    
    timeoutOccured in interface TimeoutObserver
    
    Parameters:
    w - the watchdog that timed out.
  - checkException
```
public void checkException()
                    throws Exception
```
    This method will rethrow the exception that was possibly caught during the run of the process. It will only remains valid once the process has been terminated either by 'error', timeout or manual intervention. Information will be discarded once a new process is ran.
    
    Throws:
    
    Exception - a wrapped exception over the one that was silently swallowed and stored during the process run.
  - isWatching
```
public boolean isWatching()
```
    Indicates whether or not the watchdog is still monitoring the process.
    
    Returns:
    true if the process is still running, otherwise false.
  - killedProcess
```
public boolean killedProcess()
```
    Indicates whether the last process run was killed.
    
    Returns:
    true if the process was killed false.
  - cleanUp
```
protected void cleanUp()
```
    reset the monitor flag and the process.

Class ExecuteWatchdog

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INFINITE_TIMEOUT

Constructor Detail

ExecuteWatchdog

Method Detail

start

stop

destroyProcess

timeoutOccured

checkException

isWatching

killedProcess

cleanUp