javax.realtime

Class SizeEstimator

java.lang.Object

javax.realtime.SizeEstimator

public final class SizeEstimator
extends java.lang.Object

Jamaica Real-Time Specification for Java class SizeEstimator.

This class permits to estimate the memory required for the allocation of Java objects and arrays. It determines a lower bound for the memory required to allocate all instances and arrays function reserve() will be called for.

Constructor Summary

Constructors

Constructor and Description
SizeEstimator() Constructor to create estimate with no entries.

Method Summary

Modifier and Type	Method and Description
void	clear() Restores the estimate value to zero for reuse.
long	getEstimate() getEstimate returns the current estimate in number of bytes.
void	reserve(java.lang.Class<?> clazz, int num) reserve reserves space for num instances of class clazz.
void	reserve(SizeEstimator size) reserve reserves space for the memory reserved by SizeEstimator size.
void	reserve(SizeEstimator size, int num) reserve reserves space for the num times the memory reserved by SizeEstimator size.
void	reserveArray(int length) reserveArray reserves space for an instance of a reference array of given length.
void	reserveArray(int length, java.lang.Class<?> type) reserveArray reserves space for an of an array of primitive type and length elements when estimating the size of the MemoryArea.
void	reserveLambda() Determines the size of a lambda with no closure and add it to this size estimator.
void	reserveLambda(EnclosedType first) Determines the size of a lambda with one variable in its closure and add it to this size estimator.
void	reserveLambda(EnclosedType first, EnclosedType second) Determines the size of a lambda with two variables in its closure and add it to this size estimator.
void	reserveLambda(EnclosedType first, EnclosedType second, EnclosedType... others) Determines the size of a lambda with more than two variables in its closure and add it to this size estimator.

Methods inherited from class java.lang.Object

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

Constructor Detail

SizeEstimator

public SizeEstimator()

Constructor to create estimate with no entries.

Method Detail

getEstimate

public long getEstimate()

getEstimate returns the current estimate in number of bytes.

Returns:

the current estimate.

reserve

public void reserve(java.lang.Class<?> clazz,
                    int num)

reserve reserves space for num instances of class clazz.

Parameters:

clazz - the class of the new instances

num - the number of instances.

Throws:

StaticIllegalArgumentException - if clazz is null or num is negative.

reserve

public void reserve(SizeEstimator size)

reserve reserves space for the memory reserved by SizeEstimator size.

Parameters:

size - another SizeEstimator.

Throws:

StaticIllegalArgumentException - if size is null.

reserve

public void reserve(SizeEstimator size,
                    int num)

reserve reserves space for the num times the memory reserved by SizeEstimator size.

Parameters:

size - another SizeEstimator.

num - factor to multiply the space from size with.

Throws:

StaticIllegalArgumentException - if size is null or num < 0.

reserveArray

public void reserveArray(int length)

reserveArray reserves space for an instance of a reference array of given length.

Parameters:

length - the length of the reference array we want to reserve space for.

Throws:

StaticIllegalArgumentException - if length < 0.

Since:

RTSJ V1.0.1

reserveArray

public void reserveArray(int length,
                         java.lang.Class<?> type)

reserveArray reserves space for an of an array of primitive type and length elements when estimating the size of the MemoryArea.

Parameters:

length - the length of the primitive array we want to reserve space for.

type - the primitive element type, must be one of Boolean.TYPE, Byte.TYPE, Short.TYPE, Character.TYPE, Integer.Type, Float.TYPE, Long.TYPE, or Double.TYPE.

Throws:

StaticIllegalArgumentException - iff length is negative or type is not a primitive element type.

Since:

RTSJ V1.0.1

reserveLambda

public void reserveLambda(EnclosedType first,
                          EnclosedType second,
                          EnclosedType... others)

Determines the size of a lambda with more than two variables in its closure and add it to this size estimator.

Parameters:

first - Type of first variable in closure.

second - Type of second variable in closure.

others - Types of additional variables in closure.

Since:

RTSJ 2.0

reserveLambda

public void reserveLambda(EnclosedType first,
                          EnclosedType second)

Determines the size of a lambda with two variables in its closure and add it to this size estimator.

Parameters:

first - Type of first variable in closure.

second - Type of second variable in closure.

Since:

RTSJ 2.0

reserveLambda

public void reserveLambda(EnclosedType first)

Determines the size of a lambda with one variable in its closure and add it to this size estimator.

Parameters:

first - Type of first variable in closure.

Since:

RTSJ 2.0

reserveLambda

public void reserveLambda()

Determines the size of a lambda with no closure and add it to this size estimator.

Since:

RTSJ 2.0

clear

public void clear()

Restores the estimate value to zero for reuse.

Since:

rtsj 2.0