ACE_Dynamic_Message_Strategy Class Reference

An abstract base class which provides dynamic priority evaluation methods for use by the ACE_Dynamic_Message_Queue class or any other class which needs to manage the priorities of a collection of ACE_Message_Blocks dynamically. More...

#include <Dynamic_Message_Strategy.h>

Inheritance diagram for ACE_Dynamic_Message_Strategy:

[legend]

Collaboration diagram for ACE_Dynamic_Message_Strategy:

[legend]

List of all members.

Public Types
enum	Priority_Status { PENDING = 0x01, LATE = 0x02, BEYOND_LATE = 0x04, ANY_STATUS = 0x07 }
Public Member Functions
	ACE_Dynamic_Message_Strategy (unsigned long static_bit_field_mask, unsigned long static_bit_field_shift, unsigned long dynamic_priority_max, unsigned long dynamic_priority_offset)
	Constructor.
virtual	~ACE_Dynamic_Message_Strategy (void)
	Virtual destructor.
Priority_Status	priority_status (ACE_Message_Block &mb, const ACE_Time_Value &tv)
	Updates the message's priority and returns its priority status.
unsigned long	static_bit_field_mask (void) const
	Get static bit field mask.
void	static_bit_field_mask (unsigned long)
	Set static bit field mask.
unsigned long	static_bit_field_shift (void) const
	Get left shift value to make room for static bit field.
void	static_bit_field_shift (unsigned long)
	Set left shift value to make room for static bit field.
unsigned long	dynamic_priority_max (void) const
	Get maximum supported priority value.
void	dynamic_priority_max (unsigned long)
	Set maximum supported priority value.
unsigned long	dynamic_priority_offset (void) const
	Get offset to boundary between signed range and unsigned range.
void	dynamic_priority_offset (unsigned long)
	Set offset to boundary between signed range and unsigned range.
virtual void	dump (void) const
	Dump the state of the strategy.
Protected Member Functions
virtual void	convert_priority (ACE_Time_Value &priority, const ACE_Message_Block &mb)=0
	Hook method for dynamic priority conversion.
Protected Attributes
unsigned long	static_bit_field_mask_
	This is a bit mask with all ones in the static bit field.
unsigned long	static_bit_field_shift_
unsigned long	dynamic_priority_max_
	Maximum supported priority value.
unsigned long	dynamic_priority_offset_
	Offset to boundary between signed range and unsigned range.
ACE_Time_Value	max_late_
	Maximum late time value that can be represented.
ACE_Time_Value	min_pending_
	Minimum pending time value that can be represented.
ACE_Time_Value	pending_shift_
	Time value by which to shift pending priority.

---

Detailed Description

An abstract base class which provides dynamic priority evaluation methods for use by the ACE_Dynamic_Message_Queue class or any other class which needs to manage the priorities of a collection of ACE_Message_Blocks dynamically.

Methods for deadline and laxity based priority evaluation are provided. These methods assume a specific partitioning of the message priority number into a higher order dynamic bit field and a lower order static priority bit field. The default partitioning assumes an unsigned dynamic message priority field of 22 bits and an unsigned static message priority field of 10 bits. This corresponds to the initial values of the static class members. To provide a different partitioning, assign a different set of values to the static class memebers before using the static member functions.

---

Member Enumeration Documentation

enum ACE_Dynamic_Message_Strategy::Priority_Status

Enumerator:

PENDING	Message can still make its deadline.
LATE	Message cannot make its deadline.
BEYOND_LATE	Message is so late its priority is undefined.
ANY_STATUS	Mask to match any priority status.

---

Constructor & Destructor Documentation

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_Dynamic_Message_Strategy::ACE_Dynamic_Message_Strategy	(	unsigned long	static_bit_field_mask,
		unsigned long	static_bit_field_shift,
		unsigned long	dynamic_priority_max,
		unsigned long	dynamic_priority_offset
	)

Constructor.

ACE_Dynamic_Message_Strategy::~ACE_Dynamic_Message_Strategy

(

void

)

[virtual]

Virtual destructor.

---

Member Function Documentation

ACE_Dynamic_Message_Strategy::Priority_Status ACE_Dynamic_Message_Strategy::priority_status	(	ACE_Message_Block &	mb,
		const ACE_Time_Value &	tv
	)

Updates the message's priority and returns its priority status.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE unsigned long ACE_Dynamic_Message_Strategy::static_bit_field_mask

(

void

)

const

Get static bit field mask.

ACE_INLINE void ACE_Dynamic_Message_Strategy::static_bit_field_mask

(

unsigned long

ul

)

Set static bit field mask.

ACE_INLINE unsigned long ACE_Dynamic_Message_Strategy::static_bit_field_shift

(

void

)

const

Get left shift value to make room for static bit field.

ACE_INLINE void ACE_Dynamic_Message_Strategy::static_bit_field_shift

(

unsigned long

ul

)

Set left shift value to make room for static bit field.

ACE_INLINE unsigned long ACE_Dynamic_Message_Strategy::dynamic_priority_max

(

void

)

const

Get maximum supported priority value.

ACE_INLINE void ACE_Dynamic_Message_Strategy::dynamic_priority_max

(

unsigned long

ul

)

Set maximum supported priority value.

ACE_INLINE unsigned long ACE_Dynamic_Message_Strategy::dynamic_priority_offset

(

void

)

const

Get offset to boundary between signed range and unsigned range.

ACE_INLINE void ACE_Dynamic_Message_Strategy::dynamic_priority_offset

(

unsigned long

ul

)

Set offset to boundary between signed range and unsigned range.

void ACE_Dynamic_Message_Strategy::dump

(

void

)

const [virtual]

Dump the state of the strategy.

Reimplemented in ACE_Deadline_Message_Strategy, and ACE_Laxity_Message_Strategy.

virtual void ACE_Dynamic_Message_Strategy::convert_priority	(	ACE_Time_Value &	priority,
		const ACE_Message_Block &	mb
	)			[protected, pure virtual]

Hook method for dynamic priority conversion.

Implemented in ACE_Deadline_Message_Strategy, and ACE_Laxity_Message_Strategy.

---

Member Data Documentation

unsigned long ACE_Dynamic_Message_Strategy::static_bit_field_mask_ [protected]

This is a bit mask with all ones in the static bit field.

unsigned long ACE_Dynamic_Message_Strategy::static_bit_field_shift_ [protected]

This is a left shift value to make room for static bit field: this value should be the logarithm base 2 of (static_bit_field_mask_ + 1).

unsigned long ACE_Dynamic_Message_Strategy::dynamic_priority_max_ [protected]

Maximum supported priority value.

unsigned long ACE_Dynamic_Message_Strategy::dynamic_priority_offset_ [protected]

Offset to boundary between signed range and unsigned range.

ACE_Time_Value ACE_Dynamic_Message_Strategy::max_late_ [protected]

Maximum late time value that can be represented.

ACE_Time_Value ACE_Dynamic_Message_Strategy::min_pending_ [protected]

Minimum pending time value that can be represented.

ACE_Time_Value ACE_Dynamic_Message_Strategy::pending_shift_ [protected]

Time value by which to shift pending priority.

---

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

• Dynamic_Message_Strategy.h
• Dynamic_Message_Strategy.cpp
• Dynamic_Message_Strategy.inl