com.sun.cldc.jna
Class Structure

java.lang.Object
  com.sun.cldc.jna.Structure

Direct Known Subclasses:

CurveOptions, DynamicStructure, EllipseDescriptor, FRCCommonControlData, FRCControl.DynamicControlData, LibCImpl.statImpl, LibCImpl.statImpl, NetDBImpl.hostentImpl, NetDBImpl.hostentImpl, NIVision.Range, NIVision.Rect, OpaqueStructure, RegionOfInterest, ShapeDetectionOptions, TimeImpl.timevalImpl, TimeImpl.timevalImpl

public abstract class Structure
extends Object

Abstract class for proxies to native structure types.

Field Summary

protected Pointer	backingNativeMemory
static Structure	NULL Singleton object that can be used as a NULL structure instance.

Constructor Summary

protected	Structure()
protected	Structure(Pointer backingNativeMemory)

Method Summary

void	allocateMemory() Attempt to allocate backing memory for the structure.
void	allocateMemory(int size) Attempt to allocate backing memory for the structure.
void	clear() Set the backing memory to zeros.
void	freeMemory() Free the backing memory for the structure.
Pointer	getPointer() Get the backing native memory used by this structure.
abstract void	read() Copy the fields of the struct from native memory to the Java fields
void	release() Release the backing memory for the structure, if it was malloced
abstract int	size()
String	toString() Returns a string representation of the object.
void	useMemory(Pointer m) Set the backing native memory used by this structure.
abstract void	write() Copy the java fields of the struct to native memory from the Java fields

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

backingNativeMemory

protected Pointer backingNativeMemory

NULL

public static final Structure NULL

Singleton object that can be used as a NULL structure instance.

Constructor Detail

Structure

protected Structure(Pointer backingNativeMemory)

Structure

protected Structure()

Method Detail

read

public abstract void read()

Copy the fields of the struct from native memory to the Java fields

write

public abstract void write()

Copy the java fields of the struct to native memory from the Java fields

size

public abstract int size()

Returns:

the size of the native structure

getPointer

public final Pointer getPointer()

Get the backing native memory used by this structure. May return null if allocateMemory() has not been called, or if the Structure is permantently attached to C memory.

Returns:

the memory

useMemory

public final void useMemory(Pointer m)

Set the backing native memory used by this structure.

Parameters:

m - the native memory

Throws:

IllegalStateException - if this structure already has memory allocated

allocateMemory

public void allocateMemory()
                    throws OutOfMemoryError

Attempt to allocate backing memory for the structure. This memory should be freed when not needed

Throws:

OutOfMemoryError - if backing native memory cannot be allocated.

IllegalStateException - if this structure already has memory allocated

allocateMemory

public void allocateMemory(int size)
                    throws OutOfMemoryError

Attempt to allocate backing memory for the structure.

Parameters:

size - in bytes ito allocate

Throws:

IllegalArgumentException - if the requested size is smaller than the default size

OutOfMemoryError - if backing native memory cannot be allocated.

IllegalStateException - if this structure already has memory allocated

freeMemory

public void freeMemory()
                throws IllegalStateException

Free the backing memory for the structure.

Throws:

IllegalStateException - if the memory has already been freed.

release

public void release()
             throws IllegalStateException

Release the backing memory for the structure, if it was malloced

Throws:

IllegalStateException - if the memory has already been freed.

clear

public void clear()

Set the backing memory to zeros.

toString

public String toString()

Description copied from class: Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.