casacore::ObjectID Class Reference

ObjectID: A unique identifier for distributed and other objects. More...

#include <ObjectID.h>

Public Member Functions
	ObjectID (Bool makeNull=False)
	If makeNull is True, make the null ObjectID, otherwise create a unique ObjectID. More...
	ObjectID (Int sequence, Int pid, Int time, const String &hostname)
	Create explicitly from the provided constituents. More...
	ObjectID (const ObjectID &other)
	Copy other. More...
ObjectID &	operator= (const ObjectID &other)
Bool	isNull () const
	Is this ObjectID set? More...
Bool	operator== (const ObjectID &other) const
	Compare two ObjectID's for (in)equality. More...
Bool	operator!= (const ObjectID &other) const
Bool	fromString (String &error, const String &in)
	It is useful to interconvert between strings and ObjecID's, e.g. More...
void	toString (String &out) const
	Note that out is zero'd before it is set. More...
Int	sequence () const
	Ordinarily the user does not need to get at the exact state of the, ObjectID, however it is available for those times when it is necessary. More...
Int	pid () const
Int	creationTime () const
const String &	hostName () const

Static Public Member Functions
static String	extractIDs (Block< ObjectID > &objectIDs, const String &command)
	Extract objectID strings (as set by glish script substitute.g) from a command, convert them to ObjectID objects, store those in the Block, and replace the strings by their Block indices as $OBJ::n::O where n is the index. More...

Static Private Member Functions
static Int	sequence_number ()
	Make a unique sequence number, returns 0 on first call, 1 on next,... More...

Private Attributes
Int	sequence_number_p
Int	process_id_p
Int	creation_time_p
String	hostname_p

Detailed Description

ObjectID: A unique identifier for distributed and other objects.

Intended use:

Public interface

Review Status

Reviewed By:

UNKNOWN

Date Reviewed:

before2004/08/25

Test programs:

tObjectID

Prerequisite

• none

Etymology

The ObjectID class name reflects its role as the single identifier for distributed and other user-level objects.

Synopsis

The ObjectID class is used to give a unique identifier to ``high-level'' objects in the system. Internally the ObjectID consists of a sequence number (unique within the creating process), a process id, a creation time, and a host id. Pragmatically the ObjectID should be unique with no dangers of collisions.

A special ``Null'' ObjectID is available.

Motivation

The fundamental purpose for an ObjectID is to provide a unique identifier for persistent objects, or for objects that might be accessed outside the creating processes address space.

To Do

• Nothing (hostid -> hostname on this date).

Definition at line 79 of file ObjectID.h.

Constructor & Destructor Documentation

casacore::ObjectID::ObjectID

(

Bool

makeNull = False

)

If makeNull is True, make the null ObjectID, otherwise create a unique ObjectID.

casacore::ObjectID::ObjectID	(	Int	sequence,
		Int	pid,
		Int	time,
		const String &	hostname
	)

Create explicitly from the provided constituents.

casacore::ObjectID::ObjectID

(

const ObjectID &

other

)

Copy other.

Note that if the ObjectID is embedded inside an object, the enclosing object probably does not want to copy the ObjectID since generally speaking the identity of the enclosing object should be immutable.

Member Function Documentation

Int casacore::ObjectID::creationTime ( ) const

inline

Definition at line 164 of file ObjectID.h.

References creation_time_p.

static String casacore::ObjectID::extractIDs ( Block< ObjectID > &  objectIDs, const String &  command  )

static

Extract objectID strings (as set by glish script substitute.g) from a command, convert them to ObjectID objects, store those in the Block, and replace the strings by their Block indices as $OBJ::n::O where n is the index.

Bool casacore::ObjectID::fromString	(	String &	error,
		const String &	in
	)

It is useful to interconvert between strings and ObjecID's, e.g.

when saving to FITS or writing to a table. The form of the string is:

sequence=123 host=hostname pid=pid time=time

with an optional comma between the fields. However, in general user code should not depend on the exact form of the string.

If this fails, an error message is set and the ObjectID is the null ObjectID.

const String & casacore::ObjectID::hostName ( ) const

inline

Definition at line 169 of file ObjectID.h.

References hostname_p.

Bool casacore::ObjectID::isNull

(

)

const

Is this ObjectID set?

Bool casacore::ObjectID::operator!=

(

const ObjectID &

other

)

const

ObjectID& casacore::ObjectID::operator=

(

const ObjectID &

other

)

Bool casacore::ObjectID::operator==

(

const ObjectID &

other

)

const

Compare two ObjectID's for (in)equality.

Int casacore::ObjectID::pid ( ) const

inline

Definition at line 159 of file ObjectID.h.

References process_id_p.

Int casacore::ObjectID::sequence ( ) const

inline

Ordinarily the user does not need to get at the exact state of the, ObjectID, however it is available for those times when it is necessary.

Definition at line 154 of file ObjectID.h.

References sequence_number_p.

static Int casacore::ObjectID::sequence_number ( )

staticprivate

Make a unique sequence number, returns 0 on first call, 1 on next,...

void casacore::ObjectID::toString

(

String &

out

)

const

Note that out is zero'd before it is set.

Member Data Documentation

Int casacore::ObjectID::creation_time_p

private

Definition at line 141 of file ObjectID.h.

Referenced by creationTime().

String casacore::ObjectID::hostname_p

private

Definition at line 142 of file ObjectID.h.

Referenced by hostName().

Int casacore::ObjectID::process_id_p

private

Definition at line 140 of file ObjectID.h.

Referenced by pid().

Int casacore::ObjectID::sequence_number_p

private

Definition at line 139 of file ObjectID.h.

Referenced by sequence().

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The documentation for this class was generated from the following file:

• casa/System/ObjectID.h