javax.safetycritical

Class MemoryArea

java.lang.Object

javax.safetycritical.MemoryArea

All Implemented Interfaces:

javax.realtime.AllocationContext

Direct Known Subclasses:

ImmortalMemory, ManagedMemory

@SCJAllowed(value=INFRASTRUCTURE)
public class MemoryArea
extends java.lang.Object
implements javax.realtime.AllocationContext

All allocation contexts are implemented by memory areas. This is the base-level class for all memory areas.

Version:

1.2; - December 2013

Author:

Anders P. Ravn, Aalborg University, apr@cs.aau.dk,
Hans Søndergaard, VIA University College, Denmark, hso@viauc.dk

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	backingStoreBase
protected static int	backingStoreEnd
protected static MemoryArea	currentActiveArea
protected vm.Memory	delegate
protected static MemoryArea	head Singleton reference for the immortal memory.
(package private) MemoryArea	innerArea Inner area for enterPrivateMemory.
(package private) static int	memoryLevel
(package private) MemoryArea	next
(package private) MemoryArea	prev

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MemoryArea(int size) Creates a new memory area.

Method Summary

Methods

Modifier and Type	Method and Description
(package private) static void	allocateBackingStore(int size)
(package private) void	enter(java.lang.Runnable logic) Makes this memory area the allocation context for the execution of the run() method of the instance of Runnable given in the constructor.
(package private) void	enterMemory(int size, java.lang.Runnable logic) Helper method for ManagedMemory.enterPrivateMemory
(package private) void	executeInArea(java.lang.Runnable logic) Executes logic in this memory area, with no cleanup and no pointer reset at the end.
static MemoryArea[]	getContexts(java.lang.Object object)
(package private) static MemoryArea	getCurrentMemory() Return the memory region which we are currently in.
static MemoryArea	getMemoryArea(java.lang.Object object)
int	getMemoryAreaLevel()
long	memoryConsumed()
long	memoryRemaining()
(package private) void	removeArea()
long	size()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

head

protected static MemoryArea head

Singleton reference for the immortal memory.

currentActiveArea

protected static MemoryArea currentActiveArea

backingStoreEnd

protected static int backingStoreEnd

backingStoreBase

protected static int backingStoreBase

delegate

protected vm.Memory delegate

next

MemoryArea next

prev

MemoryArea prev

memoryLevel

static int memoryLevel

innerArea

MemoryArea innerArea

Inner area for enterPrivateMemory.

Constructor Detail

MemoryArea

protected MemoryArea(int size)

Creates a new memory area.

Parameters:

size - The size of this new memory area.

Method Detail

getMemoryAreaLevel

public int getMemoryAreaLevel()

getContexts

public static MemoryArea[] getContexts(java.lang.Object object)

removeArea

void removeArea()

enter

@SCJAllowed(value=INFRASTRUCTURE)
void enter(java.lang.Runnable logic)
     throws java.lang.IllegalArgumentException

Makes this memory area the allocation context for the execution of the run() method of the instance of Runnable given in the constructor.
During this period of execution, this memory area becomes the default allocation context until another allocation context is selected or the Runnable's run method exits.

This method is like the executeInArea method, but extended with cleanup and pointer reset.

Parameters:

logic - The Runnable object whose run() method shall be executed.

Throws:

java.lang.IllegalArgumentException - Thrown if the caller is a schedulable object and logic is null.

getCurrentMemory

static MemoryArea getCurrentMemory()

Return the memory region which we are currently in.

getMemoryArea

@SCJAllowed
public static MemoryArea getMemoryArea(java.lang.Object object)

Parameters:

object - An object.

Returns:

The memory area in which object is allocated.

executeInArea

@SCJAllowed
void executeInArea(java.lang.Runnable logic)
             throws java.lang.IllegalArgumentException

Executes logic in this memory area, with no cleanup and no pointer reset at the end.

Parameters:

logic - The Runnable object whose run() method shall be executed.

Throws:

java.lang.IllegalArgumentException - If logic is null.

memoryConsumed

@SCJAllowed
public long memoryConsumed()

Specified by:

memoryConsumed in interface javax.realtime.AllocationContext

Returns:

The memory consumed (in bytes) in this memory area.

memoryRemaining

@SCJAllowed
public long memoryRemaining()

Specified by:

memoryRemaining in interface javax.realtime.AllocationContext

Returns:

The memory remaining (in bytes) in this memory area.

size

@SCJAllowed
public long size()

Specified by:

size in interface javax.realtime.AllocationContext

Returns:

The size of the current memory area in bytes.

allocateBackingStore

static void allocateBackingStore(int size)

enterMemory

void enterMemory(int size,
               java.lang.Runnable logic)

Helper method for ManagedMemory.enterPrivateMemory

Parameters:

size - The size of inner private memory

logic - The logic to be executed in inner private memory