The System class provides static methods for accessing system level resources and performing some system dependent tasks such as looking up environment values and copying memory and arrays. More...

#include <src/main/decaf/lang/System.h>

Public Member Functions
virtual	~System ()

Static Public Member Functions
static void	arraycopy (const char src, std::size_t srcPos, char dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const unsigned char src, std::size_t srcPos, unsigned char dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const short src, std::size_t srcPos, short dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const int src, std::size_t srcPos, int dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const long long src, std::size_t srcPos, long long dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const float src, std::size_t srcPos, float dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static void	arraycopy (const double src, std::size_t srcPos, double dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
template<typename E >
static void	arraycopy (const E src, std::size_t srcPos, E dest, std::size_t destPos, std::size_t length)
	Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.
static const util::Map < std::string, std::string > &	getenv ()
	Enumerates the system environment and returns a map of env variable names to the string values they hold.
static std::string	getenv (const std::string &name)
	Reads an environment value from the system and returns it as a string object.
static void	unsetenv (const std::string &name)
	Clears a set environment value if one is set.
static void	setenv (const std::string &name, const std::string &value)
	Sets the specified system property to the value given.
static long long	currentTimeMillis ()
	Returns the current time in milliseconds.
static long long	nanoTime ()
	Returns the current value of the most precise available system timer, in nanoseconds.
static int	availableProcessors ()
	Returns the number of processors available for execution of Decaf Threads.
static decaf::util::Properties &	getProperties ()
	Gets the Properties object that holds the Properties accessed from calls to getProperty and setProperty.
static std::string	getProperty (const std::string &key)
	Gets the specified System property if set, otherwise returns an empty string.
static std::string	getProperty (const std::string &key, const std::string &defaultValue)
	Gets the specified System property if set, otherwise returns the specified default value.
static std::string	setProperty (const std::string &key, const std::string &value)
	Sets the System Property to the specified value.
static std::string	clearProperty (const std::string &key)
	Clear any value associated with the system property specified.

Protected Member Functions
	System ()

Friends
class	decaf::lang::Runtime

Detailed Description

The System class provides static methods for accessing system level resources and performing some system dependent tasks such as looking up environment values and copying memory and arrays.

Since: 1.0

Constructor & Destructor Documentation

decaf::lang::System::System ( )

protected

virtual decaf::lang::System::~System ( )

inlinevirtual

Member Function Documentation

static void decaf::lang::System::arraycopy	(	const char *	src,
		std::size_t	srcPos,
		char *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

Referenced by decaf::util::concurrent::CopyOnWriteArrayList< E >::addAll(), decaf::util::concurrent::CopyOnWriteArrayList< E >::addAllAbsent(), decaf::lang::ArrayPointer< HashMapEntry * >::clone(), decaf::util::ArrayList< Pointer< ActiveMQDestination > >::ensureCapacity(), decaf::util::ArrayList< Pointer< ActiveMQDestination > >::removeAt(), and decaf::util::ArrayList< Pointer< ActiveMQDestination > >::trimToSize().

static void decaf::lang::System::arraycopy	(	const unsigned char *	src,
		std::size_t	srcPos,
		unsigned char *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

static void decaf::lang::System::arraycopy	(	const short *	src,
		std::size_t	srcPos,
		short *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

static void decaf::lang::System::arraycopy	(	const int *	src,
		std::size_t	srcPos,
		int *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

static void decaf::lang::System::arraycopy	(	const long long *	src,
		std::size_t	srcPos,
		long long *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

static void decaf::lang::System::arraycopy	(	const float *	src,
		std::size_t	srcPos,
		float *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

static void decaf::lang::System::arraycopy	(	const double *	src,
		std::size_t	srcPos,
		double *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

static

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

template<typename E >

static void decaf::lang::System::arraycopy	(	const E *	src,
		std::size_t	srcPos,
		E *	dest,
		std::size_t	destPos,
		std::size_t	length
	)

inlinestatic

Copies the number of elements specified by length from the source array starting at the given source offset specified by srcPos to the dest array starting at the given destination offset given by destPos.

Parameters

src	The source array to copy from.
srcPos	The position in the array to start copying from.
dest	The destination array to copy to.
destPos	The position in the destination array to start writing at.
length	The number of elements to copy from src to dest.

Exceptions

NullPointerException if src or dest are NULL.

References NULL.

static int decaf::lang::System::availableProcessors ( )

static

Returns the number of processors available for execution of Decaf Threads.

This value may change during a particular execution of a Decaf based application. Applications that are sensitive to the number of available processors should therefore occasionally poll this property and adjust their resource usage appropriately.

Returns: the number of available processors.

static std::string decaf::lang::System::clearProperty ( const std::string & key )

static

Clear any value associated with the system property specified.

Parameters

key	The key name of the system property to clear.

Returns: the previous value of the property named by key if there was one, otherwise returns an empty string.

Exceptions

IllegalArgumentException if key is an empty string.

static long long decaf::lang::System::currentTimeMillis ( )

static

Returns the current time in milliseconds.

Note that while the unit of time of the return value is a millisecond, the granularity of the value depends on the underlying operating system and may be larger. For example, many operating systems measure time in units of tens of milliseconds.

See the description of the class Date for a discussion of slight discrepancies that may arise between "computer time" and coordinated universal time (UTC).

Returns: the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.

static const util::Map<std::string, std::string>& decaf::lang::System::getenv ( )

static

Enumerates the system environment and returns a map of env variable names to the string values they hold.

Returns: A Map of all environment variables.

Exceptions

Exception if an error occurs while getting the Environment Map.

static std::string decaf::lang::System::getenv ( const std::string & name )

static

Reads an environment value from the system and returns it as a string object.

Parameters

name	The environment variable to read.

Returns: a string with the value from the variables or ""

Exceptions

an	Exception if an error occurs while reading the Env.

static decaf::util::Properties& decaf::lang::System::getProperties ( )

static

Gets the Properties object that holds the Properties accessed from calls to getProperty and setProperty.

If the Properties has not yet been created or are not yet initialized then they will be on the first call to a Properties accessor.

Returns: a reference to the static system Properties object.

static std::string decaf::lang::System::getProperty ( const std::string & key )

static

Gets the specified System property if set, otherwise returns an empty string.

If the Properties has not yet been created or are not yet initialized then they will be on the first call to a Properties accessor.

Parameters

key	The key name of the desired system property to retrieve.

Returns: an empty string if the named property is not set, otherwise returns the value.

Exceptions

IllegalArgumentException if key is an empty string.

static std::string decaf::lang::System::getProperty	(	const std::string &	key,
		const std::string &	defaultValue
	)

static

Gets the specified System property if set, otherwise returns the specified default value.

If the Properties has not yet been created or are not yet initialized then they will be on the first call to a Properties accessor.

Parameters

key	The key name of the desired system property to retrieve.
defaultValue	The default value to return if the key is not set in the System properties.

Returns: the value of the named system property or the defaultValue if the property isn't set..

Exceptions

IllegalArgumentException if key is an empty string.

static long long decaf::lang::System::nanoTime ( )

static

Returns the current value of the most precise available system timer, in nanoseconds.

This method can only be used to measure elapsed time and is not related to any other notion of system or wall-clock time. The value returned represents nanoseconds since some fixed but arbitrary time (perhaps in the future, so values may be negative). This method provides nanosecond precision, but not necessarily nanosecond accuracy. No guarantees are made about how frequently values change. Differences in successive calls that span greater than approximately 292 years (263 nanoseconds) will not accurately compute elapsed time due to numerical overflow.

For example, to measure how long some code takes to execute:

long long startTime = System::nanoTime(); // ... the code being measured ... long long estimatedTime = System::nanoTime() - startTime;

Returns: The current value of the system timer, in nanoseconds.

static void decaf::lang::System::setenv	(	const std::string &	name,
		const std::string &	value
	)

static

Sets the specified system property to the value given.

Parameters

name	The name of the environment variables to set.
value	The value to assign to name.

Exceptions

an	Exception if an error occurs when setting the environment variable.

static std::string decaf::lang::System::setProperty	(	const std::string &	key,
		const std::string &	value
	)

static

Sets the System Property to the specified value.

Parameters

key	The key name of the system property to set to the given value.
value	The value to assign to the key.

Returns: the previous value of the property named by key if there was one, otherwise returns an empty string.

Exceptions

IllegalArgumentException if key is an empty string.

static void decaf::lang::System::unsetenv ( const std::string & name )

static

Clears a set environment value if one is set.

Parameters

name	The environment variables to clear.

Exceptions

an	Exception if an error occurs while reading the environment.

Friends And Related Function Documentation

friend class decaf::lang::Runtime

friend

The documentation for this class was generated from the following file:

src/main/decaf/lang/System.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation