cz.ues.platform.commons.pcb.internal

Interface UESProcessManager

All Superinterfaces:

UESProcessManager

@UESComponent
public interface UESProcessManager
extends UESProcessManager

Internal interface of UESProcessManager. This interface contains methods for advanced administration of process execution and environment, and therefore should not be normally used. For common needs use public API of UESProcessManager

Since:

UES6-00

See Also:

UESProcessManager

Method Summary

Methods

Modifier and Type	Method and Description
void	forkSystemProcess() Creates the new child-process for current process and makes it active (all following commands are executed in this child-process).
<T> java.util.List<T>	getParameterChain(java.lang.String aName, java.lang.Class<T> aParamClass) Returns hierarchy of parameters from process environment.
PCB	getPCB() Returns PCB of active process.
PID	getPID() Only one process have to be active on thread.
PID	getRootPID() Returns PID of the root process.
PID	getSystemPID() Returns PID of nearest system process in branch of active PID.
boolean	isInheritedParameter(java.lang.String aName) Checks if process environment parameter under given name is owned by active process or is inherited from parent process.
void	killProcessSubtree(PID aPID) Changes active PID to given one and disposes whole subtree of given PID.
void	restoreProcess(java.io.InputStream aIn) Method restores PCB from given input stream and merges this PCB into active one.
void	startNewSystemProcess() Method switches active process to root process and creates new child-process which is made active (all following commands are executed in this child-process).
void	storeProcess(java.io.OutputStream aOut) Method stores (serializes) active PCB into given output stream.

Methods inherited from interface cz.ues.platform.commons.pcb.UESProcessManager

exitProcess, forkProcess, getParameter, setParameter, setRetainedParameter

Method Detail

getPID

PID getPID()

Only one process have to be active on thread. This method returns the current one.

Returns:

The PID of current active process.

Since:

UES6-00

getSystemPID

PID getSystemPID()

Returns PID of nearest system process in branch of active PID. If active process is system process, PID of active process is returned.

Returns:

The PID of nearest system process

Since:

UES6-00

getRootPID

PID getRootPID()

Returns PID of the root process.

Returns:

The PID of root process.

Since:

UES6-00

getPCB

PCB getPCB()

Returns PCB of active process.

Returns:

PCB of active process.

Since:

UES6-00

forkSystemProcess

void forkSystemProcess()
throws UESProcessManagerRTException

Creates the new child-process for current process and makes it active (all following commands are executed in this child-process). Block after fork must be ended by exit (to end created child-process and dispose its PCB).

This method can be used only if current process is system process (has no session process ID associated). It is not possible to fork system process from application process. Application process tree must be first exited before calling this method.

Throws:

UESProcessManagerRTException - In case fork of process failed or fork is not possible

Since:

UES6-00

startNewSystemProcess

void startNewSystemProcess()
throws UESProcessManagerRTException

Method switches active process to root process and creates new child-process which is made active (all following commands are executed in this child-process). Block after fork must be ended by exit (to end created child-process and dispose its PCB).

This method should be used with extreme caution only in situations when some new thread was started from already forked and initialized thread, but we need to use the new thread as root process (e.g. when starting local job executor thread from application and not as standalone executor server). Calling this method from other place than newly started thread can cause memory leaks and unexpected application behavior.

Throws:

UESProcessManagerRTException - In case starting of new system process failed or is not possible

Since:

UES7-02

killProcessSubtree

void killProcessSubtree(PID aPID)
throws UESProcessManagerRTException

Changes active PID to given one and disposes whole subtree of given PID. This method should be typically called before re-login, when switching users means starting of new session (result of getSystemPID should be used as method parameter). Other usage is to exit exact process we forked if we are not sure, if internally called logic did not used fork without exit.

Parameters:

aPID - PID of process to be used as new active one

Throws:

UESProcessManagerRTException - In case kill of process tree failed or kill is not possible

Since:

UES6-00

storeProcess

void storeProcess(java.io.OutputStream aOut)
throws UESProcessManagerRTException

Method stores (serializes) active PCB into given output stream. Active PCB must be leaf of process tree. It is not possible to store process with child processes.

Parameters:

aOut - Output stream used for PCB serialization

Throws:

UESProcessManagerRTException - In case serialization of process failed or serialization is not possible due to unfulfilled preconditions.

Since:

UES6-00

restoreProcess

void restoreProcess(java.io.InputStream aIn)
throws UESProcessManagerRTException

Method restores PCB from given input stream and merges this PCB into active one. Active PCB must represents system process and be leaf of process tree. It is not possible to restore process into application process or into process with child processes.

Parameters:

aIn - Input stream with serialized PCB

Throws:

UESProcessManagerRTException - In case restore of process failed or restoring is not possible due to unfulfilled preconditions.

Since:

UES6-00

isInheritedParameter

boolean isInheritedParameter(java.lang.String aName)

Checks if process environment parameter under given name is owned by active process or is inherited from parent process.

Parameters:

aName - Name of parameter

Returns:

True if parameter is inherited, false if parameter is own (or is not set at all)

Since:

UES6-00

getParameterChain

<T> java.util.List<T> getParameterChain(java.lang.String aName,
java.lang.Class<T> aParamClass)
throws UESProcessManagerRTException

Returns hierarchy of parameters from process environment. Size of returned list corresponds to nested level of active PCB starting with zero position representing root PCB. Only own parameters are present in list. In case some parameter is inherited on concrete level, null is added as value at corresponding position in list.
All elements in returned list should be always handled as immutable. It is not recommended to change their values in any way!

Type Parameters:

T - Type of parameter value

Parameters:

aName - Name of parameter

aParamClass - Class of parameter value

Returns:

Parameter chain

Throws:

UESProcessManagerRTException - In case reading of parameter chain fails or read is not possible(e.g. given class does not match type of parameter stored under given name)

Since:

UES6-06