javax.realtime

Class VTMemory

java.lang.Object

javax.realtime.MemoryArea

javax.realtime.ScopedMemory

javax.realtime.VTMemory

public class VTMemory
extends ScopedMemory

VTMemory is similar to LTMemory except that the execution time of an allocation from a VTMemory area need not complete in linear time.

Methods from VTMemory should be overridden only by methods that use super.

In JamaicaVM, the actual size will never be increased dynamically, i.e., it remains at the initial value.

In JamaicaVM, the memory space for this VTMemory area is allocated from the normal Java heap (HeapMemory), i.e., it is not depending on an external memory source such as a call to the C function malloc() . This implies that the creation of a VTMemory may fail if the available memory on the Java heap is low.

Constructor Summary

Constructors

Constructor and Description
VTMemory(long size) Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, null).
VTMemory(long initialSizeInBytes, long maxSizeInBytes) Equivalent to VTMemory(long, long, Runnable) with the argument list (initialSizeInBytes, maxSizeInBytes, null).
VTMemory(long initialSizeInBytes, long maxSizeInBytes, Runnable logic) Creates a VTMemory with the given parameters.
VTMemory(long size, Runnable logic) Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, logic).
VTMemory(SizeEstimator size) Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, null).
VTMemory(SizeEstimator size, Runnable logic) Equivalent to VTMemory(long, long, Runnable) with the argument list (size.getEstimate(), size.getEstimate(), logic).
VTMemory(SizeEstimator initial, SizeEstimator maximum) Equivalent to VTMemory(long, long, Runnable) with the argument list (initial.getEstimate(), maximum.getEstimate(), null).
VTMemory(SizeEstimator initial, SizeEstimator maximum, Runnable logic) Equivalent to VTMemory(long, long, Runnable) with the argument list (initial.getEstimate(), maximum.getEstimate(), logic).

Method Summary

Modifier and Type	Method and Description
String	toString() Creates a string representing this object.

Methods inherited from class javax.realtime.ScopedMemory

enter, enter, executeInArea, getMaximumSize, getPortal, getReferenceCount, join, join, joinAndEnter, joinAndEnter, joinAndEnter, joinAndEnter, memoryConsumed, memoryRemaining, newArray, newInstance, newInstance, setPortal, size

Methods inherited from class javax.realtime.MemoryArea

enter, enter, enter, enter, enter, executeInArea, executeInArea, executeInArea, executeInArea, executeInArea, getMemoryArea, mayHoldReferenceTo, mayHoldReferenceTo, newArrayInArea

Methods inherited from class java.lang.Object

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

Constructor Detail

VTMemory

public VTMemory(long initialSizeInBytes,
                long maxSizeInBytes)

Equivalent to VTMemory(long, long, Runnable) with the argument list (initialSizeInBytes, maxSizeInBytes, null).

In JamaicaVM, the size of an VTMemory is not increased dynamically. If the initial size is less than maxSizeInBytes, it will be set to maxSizeInBytes.

Throws:

IllegalArgumentException - when initialSizeInBytes is greater than maxSizeInBytes or when initialSizeInBytes or maxSizeInBytes is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

initialSizeInBytes - The size in bytes of the memory to initially allocate for this area.

maxSizeInBytes - The maximum size in bytes to which this memory area's size may grow.

VTMemory

public VTMemory(long initialSizeInBytes,
                long maxSizeInBytes,
                Runnable logic)

Creates a VTMemory with the given parameters.

In JamaicaVM, the size of an VTMemory is not increased dynamically. If the initial size is less than maxSizeInBytes, it will be set to maxSizeInBytes.

Throws:

IllegalArgumentException - when initialSizeInBytes is greater than maxSizeInBytes, or when initialSizeInBytes or maxSizeInBytes is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

IllegalAssignmentError - when storing logic in this would violate the assignment rules.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

initialSizeInBytes - The size in bytes of the memory to initially allocate for this area.

maxSizeInBytes - The maximum size in bytes to which this memory area's size may grow.

logic - An instance of Runnable whose run() method will use this as its initial memory area. When logic is null, this constructor is equivalent to VTMemory(long initial, long maximum).

VTMemory

public VTMemory(SizeEstimator initial,
                SizeEstimator maximum)

Equivalent to VTMemory(long, long, Runnable) with the argument list (initial.getEstimate(), maximum.getEstimate(), null).

In JamaicaVM, the size of an VTMemory is not increased dynamically. If the initial size is less than maximum, it will be set to maximum.

Throws:

IllegalArgumentException - when initial is null, maximum is null, initial.getEstimate() is greater than maximum.getEstimate(), or when initial.getEstimate() is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

initial - The size in bytes of the memory to initially allocate for this area estimated by an instance of SizeEstimator.

maximum - The maximum size in bytes to which this memory area's size may grow estimated by an instance of SizeEstimator.

VTMemory

public VTMemory(SizeEstimator initial,
                SizeEstimator maximum,
                Runnable logic)

Equivalent to VTMemory(long, long, Runnable) with the argument list (initial.getEstimate(), maximum.getEstimate(), logic).

In JamaicaVM, the size of an VTMemory is not increased dynamically. If the initial size is less than maximum, it will be set to maximum.

Throws:

IllegalArgumentException - when initial is null, maximum is null, initial.getEstimate() is greater than maximum.getEstimate(), or when initial.getEstimate() is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

IllegalAssignmentError - when storing logic in this would violate the assignment rules.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

initial - The size in bytes of the memory to initially allocate for this area estimated by an instance of SizeEstimator.

maximum - The maximum size in bytes to which this memory area's size may grow estimated by an instance of SizeEstimator.

logic - An instance of Runnable whose run() method will use this as its initial memory area. When logic is null, this constructor is equivalent to VTMemory(SizeEstimator initial, SizeEstimator maximum).

VTMemory

public VTMemory(long size)

Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, null).

Throws:

IllegalArgumentException - when size is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

size - The size in bytes of the memory to allocate for this area. This memory must be committed before the completion of the constructor.

Since:

RTSJ 1.0.1

VTMemory

public VTMemory(long size,
                Runnable logic)

Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, logic).

Throws:

IllegalArgumentException - when size is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

IllegalAssignmentError - when storing logic in this would violate the assignment rules.

Parameters:

size - The size in bytes of the memory to allocate for this area. This memory must be committed before the completion of the constructor.

logic - The run() of the given Runnable will be executed using this as its initial memory area. When logic is null, this constructor is equivalent to VTMemory(long size).

Since:

RTSJ 1.0.1

VTMemory

public VTMemory(SizeEstimator size)

Equivalent to VTMemory(long, long, Runnable) with the argument list (size, size, null).

Throws:

IllegalArgumentException - when size is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

size - The size in bytes of the memory to allocate for this area. This memory must be committed before the completion of the constructor.

Since:

RTSJ 1.0.1

VTMemory

public VTMemory(SizeEstimator size,
                Runnable logic)

Equivalent to VTMemory(long, long, Runnable) with the argument list (size.getEstimate(), size.getEstimate(), logic).

Throws:

IllegalArgumentException - when size is null, or size.getEstimate() is less than zero.

OutOfMemoryError - when there is insufficient memory for the VTMemory object or for the backing memory.

IllegalAssignmentError - when storing logic in this would violate the assignment rules.

UnsupportedOperationException - In JamaicaVM when a user-defined subclass does not know about the memory area implementation details.

Parameters:

size - An instance of SizeEstimator used to give an estimate of the initial size. This memory must be committed before the completion of the constructor.

logic - The run() of the given Runnable will be executed using this as its initial memory area. When logic is null, this constructor is equivalent to VTMemory(SizeEstimator size).

Since:

RTSJ 1.0.1

Method Detail

toString

public String toString()

Creates a string representing this object. The string is of the form

  (VTMemory) ScopedMemory#<num>
 

where <num> uniquely identifies the VTMemory area.

Overrides:

toString in class ScopedMemory

Returns:

a string representation of this.