com.heirloomcomputing.epli.runtime

Class Area

java.lang.Object

com.heirloomcomputing.epli.runtime.Area

public class Area
extends java.lang.Object

Simulate the PL/I AREA, a block of memory in which other objects can be allocated and referenced. In Java generated by the Elastic PL/I compiler, this is simply a list of objects that are related. The Offset is returned when a PL/I variable is "allocated within" an Area. PL/I OFFSETs generated as Java Offsets hold references to standard Java objects allocated on the Java heap but are associated with an Area to use that class's facilities to marshal and un-marshal associated objects "within" Area for I/O operations. It has less to do with actually allocating the alloted space defined for an Area.

Author:

Heirloom Computing, Inc.

Constructor Summary

Constructors

Constructor and Description
Area() constructor - create a null Area
Area(java.lang.String name, int size) constructor - create a Area of a certain size and given name

Method Summary

Modifier and Type	Method and Description
Pointer<?>	add(Pointer<?> ptr) Add a Pointer (or its subclass Offset) to an area
void	allocate(int size) Allocate or reallocate an area of a certain size
void	free() Free an area of all objects within it
void	free(Pointer<?> ptr) Free a specific Pointer (or its subclass Offset) within an Area
void	fromBytes(byte[] bytes) convert a byte array (from an I/O or Group assignment) to this Area
int	getItems() return the number of allocated items
int	getLength() return the allocated length of the Area
int	getSize() return the declared size of the Area
byte[]	toBytes() convert Area to a byte array (for an I/O or Group assignment)

Methods inherited from class java.lang.Object

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

Constructor Detail

Area

public Area()

constructor - create a null Area

Area

public Area(java.lang.String name,
            int size)

constructor - create a Area of a certain size and given name

Parameters:

name - - the name of this area (for error messages)

size - - size of the area

Method Detail

getSize

public int getSize()

return the declared size of the Area

getLength

public int getLength()

return the allocated length of the Area

getItems

public int getItems()

return the number of allocated items

allocate

public void allocate(int size)

Allocate or reallocate an area of a certain size

Parameters:

size - - the size of the area

add

public Pointer<?> add(Pointer<?> ptr)

Add a Pointer (or its subclass Offset) to an area

Parameters:

ptr - - the Pointer or Offset to add to this area

Returns:

the same pointer or offset

free

public void free(Pointer<?> ptr)

Free a specific Pointer (or its subclass Offset) within an Area

Parameters:

ptr - - a Pointer or Offset to free within this Area

Throws:

AREA - CONDITION if not allocated

free

public void free()

Free an area of all objects within it

fromBytes

public void fromBytes(byte[] bytes)

convert a byte array (from an I/O or Group assignment) to this Area

Parameters:

bytes - - the byte array that was built with toBytes()

toBytes

public byte[] toBytes()

convert Area to a byte array (for an I/O or Group assignment)

Returns:

the byte array of the Area created from a ByteBuilder which includes types, lengths as well as data