ej.bon

Class Immortals

java.lang.Object

ej.bon.Immortals

public class Immortals
extends Object

This class gives access to the global immortal objects pool.

An immortal object has two major properties:

1. it is not managed by the garbage collector,
2. it does not move around in memory, i.e. its physical memory location remains the same forever.

Constructor Summary

Constructors

Constructor and Description
Immortals()

Method Summary

Modifier and Type	Method and Description
static <T> T	deepImmortal(T root) Turns the given object and all objects referred from it into immortal objects.
static long	freeMemory() Returns the amount of free immortal memory still available.
static boolean	isImmortal(Object o) Gets whether an object is immortal or not.
static void	run(Runnable runnable) Calls the method Runnable.run() of the given runnable.
static <T> T	setImmortal(T o) Turns the given object into an immortal object.
static long	totalMemory() Returns the total amount of immortal memory.

Methods inherited from class java.lang.Object

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

Constructor Detail

Immortals

public Immortals()

Method Detail

deepImmortal

public static <T> T deepImmortal(T root)

Turns the given object and all objects referred from it into immortal objects.

Weakly reachable objects are not turned into immortal objects.

Type Parameters:

T - the root object type

Parameters:

root - the root of the objects graph to turn into immortal

Returns:

the given object turned into immortal

freeMemory

public static long freeMemory()

Returns the amount of free immortal memory still available.

Returns:

the amount of free immortal memory

isImmortal

public static boolean isImmortal(Object o)

Gets whether an object is immortal or not.

An object is immortal:

• if it has been declared as immortal calling setImmortal(Object),
• if it is immutable.

Parameters:

o - the object to check

Returns:

true if the queried object is immortal or immutable, false otherwise

Throws:

NullPointerException - if given object is null

See Also:

Immutables.isImmutable(Object)

run

public static void run(Runnable runnable)

Calls the method Runnable.run() of the given runnable.

All the objects allocated in the context of this method are directly allocated as immortals. While the Runnable.run() method of the runnable executes all created objects are allocated as immortal objects.

Parameters:

runnable - the runnable to execute

Throws:

NullPointerException - if the given runnable is null

setImmortal

public static <T> T setImmortal(T o)

Turns the given object into an immortal object.

If the received object was immutable, it remains immutable.

If the object was already immortal, it remains immortal.

If the object was a reclaimable object it turns into an immortal object. Upon success, the returned object is immortal, otherwise an OutOfMemoryError is thrown.

Type Parameters:

T - the object type

Parameters:

o - the object to turn into an immortal

Returns:

the given object turned into immortal

Throws:

OutOfMemoryError - if the immortal memory is full

totalMemory

public static long totalMemory()

Returns the total amount of immortal memory.

Note that the amount of memory required to hold an object of any given type may be implementation-dependent.

Returns:

the total amount of immortal memory