javax.realtime
Class MemoryArea

java.lang.Object
  javax.realtime.MemoryArea

Direct Known Subclasses:

HeapMemory, ImmortalMemory, ImmortalPhysicalMemory, ScopedMemory

public abstract class MemoryArea

extends java.lang.Object

MemoryArea is the abstract base class of all classes dealing with the representation of allocatable memory areas, including the immortal memory area, physical memory and scoped memory areas. This is an abstract class, but no method in this class is abstract. An application should not subclass MemoryArea without complete knowledge of its implementation details.

Field Summary

protected java.lang.Runnable	logic
protected SizeEstimator	sizeEstimator
protected long	sizeInBytes

Constructor Summary

protected	MemoryArea(long sizeInBytes) Create an instance of MemoryArea.
protected	MemoryArea(long sizeInBytes, java.lang.Runnable logic) Constructor.
protected	MemoryArea(SizeEstimator sizeEstimator) Create an instance of MemoryArea.
protected	MemoryArea(SizeEstimator sizeEstimator, java.lang.Runnable logic) Create an instance of MemoryArea.

Method Summary

void	enter() Associate this memory area with the current schedulable object for the duration of the execution of the run() method of the instance of Runnable given in the constructor.
void	enter(java.lang.Runnable logic) Associate this memory area with the current schedulable object for the duration of the execution of the run() method of the given Runnable.
void	executeInArea(java.lang.Runnable logic) Execute the run() method from the logic parameter using this memory area as the current allocation context.
static MemoryArea	getMemoryArea(java.lang.Object object) Gets the MemoryArea in which the given object is located.
long	memoryConsumed() For memory areas where memory is freed under program control this returns an exact count, in bytes, of the memory currently used by the system for the allocated objects.
long	memoryRemaining() An approximation to the total amount of memory currently available for future allocated objects, measured in bytes.
java.lang.Object	newArray(java.lang.Class type, int number) Allocate an array of the given type in this memory area.
java.lang.Object	newInstance(java.lang.Class type)
java.lang.Object	newInstance(java.lang.reflect.Constructor c, java.lang.Object[] args) Allocate an object in this memory area.

Methods inherited from class java.lang.Object

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

Field Detail

sizeInBytes

protected long sizeInBytes

logic

protected java.lang.Runnable logic

sizeEstimator

protected SizeEstimator sizeEstimator

Constructor Detail

MemoryArea

protected MemoryArea(long sizeInBytes)

Create an instance of MemoryArea.

Parameters:

sizeInBytes - The size of MemoryArea to allocate, in bytes.

MemoryArea

protected MemoryArea(long sizeInBytes,
                     java.lang.Runnable logic)

Constructor.

Parameters:

sizeInBytes - The size of MemoryArea to allocate, in bytes.

logic - The run() method of this object will be called whenever enter() is called. If logic is null, this constructor is equivalent to MemoryArea(long size).

MemoryArea

protected MemoryArea(SizeEstimator sizeEstimator)

Create an instance of MemoryArea.

Parameters:

sizeEstimator - A SizeEstimator object which indicates the amount of memory required by this MemoryArea.

MemoryArea

protected MemoryArea(SizeEstimator sizeEstimator,
                     java.lang.Runnable logic)

Create an instance of MemoryArea.

Parameters:

sizeEstimator - A SizeEstimator object which indicates the amount of memory required by this MemoryArea.

logic - The Runnable object whose run() method should be invoked.

Method Detail

enter

public void enter()
           throws ScopedCycleException

Associate this memory area with the current schedulable object for the duration of 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 default allocation context is selected (using enter, or executeInArea(java.lang.Runnable)) or the enter method exits

Throws:

ScopedCycleException

ScopedCycleException

enter

public void enter(java.lang.Runnable logic)
           throws ScopedCycleException

Associate this memory area with the current schedulable object for the duration of the execution of the run() method of the given Runnable. During this period of execution, this memory area becomes the default allocation context until another default allocation context is selected (using enter, or executeInArea(java.lang.Runnable)) or the enter

Parameters:

logic - The Runnable object whose run() method should be invoked.

Throws:

ScopedCycleException

ScopedCycleException

executeInArea

public void executeInArea(java.lang.Runnable logic)
                   throws ScopedCycleException

Execute the run() method from the logic parameter using this memory area as the current allocation context. The effect of executeInArea on the scope stack is specified in the subclasses of MemoryArea.

Parameters:

logic - The runnable object whose run() method should be executed.

Throws:

ScopedCycleException

ScopedCycleException

getMemoryArea

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

Gets the MemoryArea in which the given object is located.

Parameters:

object -

Returns:

The instance of MemoryArea from which object was allocated.

Not currently implemented

memoryConsumed

public long memoryConsumed()

For memory areas where memory is freed under program control this returns an exact count, in bytes, of the memory currently used by the system for the allocated objects. For memory areas (such as heap) where the definition of "used" is imprecise, this returns the best value it can generate in constant time.

Returns:

the memory consumed

Not currently implemented

memoryRemaining

public long memoryRemaining()

An approximation to the total amount of memory currently available for future allocated objects, measured in bytes.

Returns:

the memory remaining

Not currently implemented

newArray

public java.lang.Object newArray(java.lang.Class type,
                                 int number)
                          throws java.lang.IllegalAccessException,
                                 java.lang.InstantiationException

Allocate an array of the given type in this memory area. This method may be concurrently used by multiple threads.

Parameters:

type - The class of the elements of the new array. To create an array of a primitive type use a type such as Integer.TYPE (which would call for an array of the primitive int type.)

number - The number of elements in the new array.

Returns:

A new array of class type, of number elements.

Throws:

IllegalAccessException

InstantiationException

- Not currently implemented

java.lang.IllegalAccessException

java.lang.InstantiationException

newInstance

public java.lang.Object newInstance(java.lang.Class type)
                             throws java.lang.IllegalAccessException,
                                    java.lang.InstantiationException

Parameters:

type -

Returns:

object allocated

Throws:

IllegalAccessException

InstantiationException

- Not currently implemented

java.lang.IllegalAccessException

java.lang.InstantiationException

newInstance

public java.lang.Object newInstance(java.lang.reflect.Constructor c,
                                    java.lang.Object[] args)
                             throws java.lang.IllegalAccessException,
                                    java.lang.InstantiationException

Allocate an object in this memory area. This method may be concurrently used by multiple threads.

Parameters:

c - The constructor for the new instance.

args - An array of arguments to pass to the constructor.

Returns:

A new instance of the object constructed by c.

Throws:

IllegalAccessException

InstantiationException

- Not currently implemented

java.lang.IllegalAccessException

java.lang.InstantiationException