java::lang::System Class Reference

The System class contains several useful class fields and methods. More...

#include <java_lang_System.h>

Inheritance diagram for java::lang::System:

[legend]Collaboration diagram for java::lang::System:

[legend]List of all members.

Public Types
enum	{   xmogDefaultFlags = xmog_base::GLOBAL, xmogMajorVersion = 3, xmogMinorVersion = 2, xmogPatchVersion = 9,   xmogBuildNumber = 2047 }
typedef ::xmog_java_array_template< ::java::lang::System >	array1D
typedef ::xmog_java_array_template< ::xmog_java_array_template< ::java::lang::System > >	array2D
Static Public Member Functions
static void	arraycopy (const ::java::lang::Object &src, jint srcPos, const ::java::lang::Object &dest, jint destPos, jint length,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array.
static jlong	currentTimeMillis (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns the current time in milliseconds.
static void	exit (jint status,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Terminates the currently running Java Virtual Machine.
static void	gc (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Runs the garbage collector.
::java::lang::String	getenv (const ::java::lang::String &name,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Gets an environment variable.
::java::util::Properties	getProperties (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Determines the current system properties.
::java::lang::String	getProperty (const ::java::lang::String &key, const ::java::lang::String &def,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Gets the system property indicated by the specified key.
::java::lang::String	getProperty (const ::java::lang::String &key,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Gets the system property indicated by the specified key.
::java::lang::SecurityManager	getSecurityManager (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Gets the system security interface.
static jint	identityHashCode (const ::java::lang::Object &x,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns the same hash code for the given object as would be returned by the default method hashCode(), whether or not the given object's class overrides hashCode().
static void	load (const ::java::lang::String &filename,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Loads a code file with the specified filename from the local file system as a dynamic library.
static void	loadLibrary (const ::java::lang::String &libname,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Loads the system library specified by the libname argument.
::java::lang::String	mapLibraryName (const ::java::lang::String &libname,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Maps a library name into a platform-specific string representing a native library.
static void	runFinalization (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Runs the finalization methods of any objects pending finalization.
static void	runFinalizersOnExit (bool value,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Enable or disable finalization on exit; doing so specifies that the finalizers of all objects that have finalizers that have not yet been automatically invoked are to be run before the Java runtime exits.
static void	setErr (const ::java::io::PrintStream &err,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Reassigns the "standard" error output stream.
static void	setIn (const ::java::io::InputStream &in,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Reassigns the "standard" input stream.
static void	setOut (const ::java::io::PrintStream &out,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Reassigns the "standard" output stream.
static void	setProperties (const ::java::util::Properties &props,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Sets the system properties to the Properties argument.
::java::lang::String	setProperty (const ::java::lang::String &key, const ::java::lang::String &value,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Sets the system property indicated by the specified key.
static void	setSecurityManager (const ::java::lang::SecurityManager &s,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Sets the System security.
Static Public Attributes
::java::io::PrintStream	err
	The "standard" error output stream.
::java::io::InputStream	in
	The "standard" input stream.
::java::io::PrintStream	out
	The "standard" output stream.

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Detailed Description

The System class contains several useful class fields and methods.

It cannot be instantiated.

Among the facilities provided by the System class are standard input, standard output, and error output streams; access to externally defined "properties"; a means of loading files and libraries; and a utility method for quickly copying a portion of an array.

Author:

Arthur van Hoff

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Member Function Documentation

static void java::lang::System::arraycopy (  const ::java::lang::Object &  src, jint  srcPos, const ::java::lang::Object &  dest, jint  destPos, jint  length, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array. A subsequence of array components are copied from the source array referenced by src to the destination array referenced by dest. The number of components copied is equal to the length argument. The components at positions srcPos through srcPos+length-1 in the source array are copied into positions destPos through destPos+length-1, respectively, of the destination array. If the src and dest arguments refer to the same array object, then the copying is performed as if the components at positions srcPos through srcPos+length-1 were first copied to a temporary array with length components and then the contents of the temporary array were copied into positions destPos through destPos+length-1 of the destination array. If dest is null, then a NullPointerException is thrown. If src is null, then a NullPointerException is thrown and the destination array is not modified. Otherwise, if any of the following is true, an ArrayStoreException is thrown and the destination is not modified: The src argument refers to an object that is not an array. The dest argument refers to an object that is not an array. The src argument and dest argument refer to arrays whose component types are different primitive types. The src argument refers to an array with a primitive component type and the dest argument refers to an array with a reference component type. The src argument refers to an array with a reference component type and the dest argument refers to an array with a primitive component type. Otherwise, if any of the following is true, an IndexOutOfBoundsException is thrown and the destination is not modified: The srcPos argument is negative. The destPos argument is negative. The length argument is negative. srcPos+length is greater than src.length, the length of the source array. destPos+length is greater than dest.length, the length of the destination array. Otherwise, if any actual component of the source array from position srcPos through srcPos+length-1 cannot be converted to the component type of the destination array by assignment conversion, an ArrayStoreException is thrown. In this case, let k be the smallest nonnegative integer less than length such that src[srcPos+k] cannot be converted to the component type of the destination array; when the exception is thrown, source array components from positions srcPos through srcPos+k-1 will already have been copied to destination array positions destPos through destPos+k-1 and no other positions of the destination array will have been modified. (Because of the restrictions already itemized, this paragraph effectively applies only to the situation where both arrays have component types that are reference types.) Parameters: src  the source array. srcPos  starting position in the source array. dest  the destination array. destPos  starting position in the destination data. length  the number of array elements to be copied. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static jlong java::lang::System::currentTimeMillis (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [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). Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.

static void java::lang::System::exit (  jint  status, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Terminates the currently running Java Virtual Machine. The argument serves as a status code; by convention, a nonzero status code indicates abnormal termination. This method calls the exit method in class Runtime. This method never returns normally. The call System.exit(n) is effectively equivalent to the call: <blockquote> Runtime.getRuntime().exit(n) </blockquote> Parameters: status  exit status. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::gc (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Runs the garbage collector. Calling the gc method suggests that the Java Virtual Machine expend effort toward recycling unused objects in order to make the memory they currently occupy available for quick reuse. When control returns from the method call, the Java Virtual Machine has made a best effort to reclaim space from all discarded objects. The call System.gc() is effectively equivalent to the call: <blockquote> Runtime.getRuntime().gc() </blockquote> Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

::java::lang::String java::lang::System::getenv (  const ::java::lang::String &  name, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Gets an environment variable. An environment variable is a system-dependent external variable that has a string value. Parameters: name  of the environment variable p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the value of the variable, or null if the variable is not defined.

::java::util::Properties java::lang::System::getProperties (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Determines the current system properties. First, if there is a security manager, its checkPropertiesAccess method is called with no arguments. This may result in a security exception. The current set of system properties for use by the method is returned as a Properties object. If there is no current set of system properties, a set of system properties is first created and initialized. This set of system properties always includes values for the following keys: Key Description of Associated Value java.version Java Runtime Environment version java.vendor Java Runtime Environment vendor</tr java.vendor.url Java vendor URL java.home Java installation directory java.vm.specification.version Java Virtual Machine specification version java.vm.specification.vendor Java Virtual Machine specification vendor java.vm.specification.name Java Virtual Machine specification name java.vm.version Java Virtual Machine implementation version java.vm.vendor Java Virtual Machine implementation vendor java.vm.name Java Virtual Machine implementation name java.specification.version Java Runtime Environment specification version java.specification.vendor Java Runtime Environment specification vendor java.specification.name Java Runtime Environment specification name java.class.version Java class format version number java.class.path Java class path java.library.path List of paths to search when loading libraries java.io.tmpdir Default temp file path java.compiler Name of JIT compiler to use java.ext.dirs Path of extension directory or directories os.name Operating system name os.arch Operating system architecture os.version Operating system version file.separator File separator ("/" on UNIX) path.separator Path separator (":" on UNIX) line.separator Line separator ("\n" on UNIX) user.name User's account name user.home User's home directory user.dir User's current working directory Multiple paths in a system property value are separated by the path separator character of the platform. Note that even if the security manager does not permit the getProperties operation, it may choose to permit the operation. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the system properties

::java::lang::String java::lang::System::getProperty (  const ::java::lang::String &  key, const ::java::lang::String &  def, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Gets the system property indicated by the specified key. First, if there is a security manager, its checkPropertyAccess method is called with the key as its argument. If there is no current set of system properties, a set of system properties is first created and initialized in the same manner as for the getProperties method. Parameters: key  the name of the system property. def  a default value. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the string value of the system property, or the default value if there is no property with that key.

::java::lang::String java::lang::System::getProperty (  const ::java::lang::String &  key, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Gets the system property indicated by the specified key. First, if there is a security manager, its checkPropertyAccess method is called with the key as its argument. This may result in a SecurityException. If there is no current set of system properties, a set of system properties is first created and initialized in the same manner as for the getProperties method. Parameters: key  the name of the system property. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the string value of the system property, or null if there is no property with that key.

::java::lang::SecurityManager java::lang::System::getSecurityManager (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Gets the system security interface. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: if a security manager has already been established for the current application, then that security manager is returned; otherwise, null is returned.

static jint java::lang::System::identityHashCode (  const ::java::lang::Object &  x, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Returns the same hash code for the given object as would be returned by the default method hashCode(), whether or not the given object's class overrides hashCode(). The hash code for the null reference is zero. Parameters: x  object for which the hashCode is to be calculated p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the hashCode

static void java::lang::System::load (  const ::java::lang::String &  filename, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Loads a code file with the specified filename from the local file system as a dynamic library. The filename argument must be a complete path name. The call System.load(name) is effectively equivalent to the call: <blockquote> Runtime.getRuntime().load(name) </blockquote> Parameters: filename  the file to load. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::loadLibrary (  const ::java::lang::String &  libname, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Loads the system library specified by the libname argument. The manner in which a library name is mapped to the actual system library is system dependent. The call System.loadLibrary(name) is effectively equivalent to the call <blockquote> Runtime.getRuntime().loadLibrary(name) </blockquote> Parameters: libname  the name of the library. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

::java::lang::String java::lang::System::mapLibraryName (  const ::java::lang::String &  libname, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Maps a library name into a platform-specific string representing a native library. Parameters: libname  the name of the library. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: a platform-dependent native library name.

static void java::lang::System::runFinalization (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Runs the finalization methods of any objects pending finalization. Calling this method suggests that the Java Virtual Machine expend effort toward running the finalize methods of objects that have been found to be discarded but whose finalize methods have not yet been run. When control returns from the method call, the Java Virtual Machine has made a best effort to complete all outstanding finalizations. The call System.runFinalization() is effectively equivalent to the call: <blockquote> Runtime.getRuntime().runFinalization() </blockquote> Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::runFinalizersOnExit (  bool  value, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Enable or disable finalization on exit; doing so specifies that the finalizers of all objects that have finalizers that have not yet been automatically invoked are to be run before the Java runtime exits. By default, finalization on exit is disabled. If there is a security manager, its checkExit method is first called with 0 as its argument to ensure the exit is allowed. This could result in a SecurityException. Parameters: value  indicating enabling or disabling of finalization p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::setErr (  const ::java::io::PrintStream &  err, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Reassigns the "standard" error output stream. First, if there is a security manager, its checkPermission method is called with a RuntimePermission("setIO") permission to see if it's ok to reassign the "standard" error output stream. Parameters: err  the new standard error output stream. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::setIn (  const ::java::io::InputStream &  in, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Reassigns the "standard" input stream. First, if there is a security manager, its checkPermission method is called with a RuntimePermission("setIO") permission to see if it's ok to reassign the "standard" input stream. Parameters: in  the new standard input stream. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::setOut (  const ::java::io::PrintStream &  out, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Reassigns the "standard" output stream. First, if there is a security manager, its checkPermission method is called with a RuntimePermission("setIO") permission to see if it's ok to reassign the "standard" output stream. Parameters: out  the new standard output stream p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

static void java::lang::System::setProperties (  const ::java::util::Properties &  props, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Sets the system properties to the Properties argument. First, if there is a security manager, its checkPropertiesAccess method is called with no arguments. This may result in a security exception. The argument becomes the current set of system properties for use by the method. If the argument is null, then the current set of system properties is forgotten. Parameters: props  the new system properties. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

::java::lang::String java::lang::System::setProperty (  const ::java::lang::String &  key, const ::java::lang::String &  value, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Sets the system property indicated by the specified key. First, if a security manager exists, its SecurityManager.checkPermission method is called with a PropertyPermission(key, "write") permission. This may result in a SecurityException being thrown. If no exception is thrown, the specified property is set to the given value. Parameters: key  the name of the system property. value  the value of the system property. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the previous value of the system property, or null if it did not have one.

static void java::lang::System::setSecurityManager (  const ::java::lang::SecurityManager &  s, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [static]

Sets the System security. If there is a security manager already installed, this method first calls the security manager's checkPermission method with a RuntimePermission("setSecurityManager") permission to ensure it's ok to replace the existing security manager. This may result in throwing a SecurityException. Otherwise, the argument is established as the current security manager. If the argument is null and no security manager has been established, then no action is taken and the method simply returns. Parameters: s  the security manager. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns:

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Member Data Documentation

::java::io::PrintStream java::lang::System::err [static]

The "standard" error output stream. This stream is already open and ready to accept output data. Typically this stream corresponds to display output or another output destination specified by the host environment or user. By convention, this output stream is used to display error messages or other information that should come to the immediate attention of a user even if the principal output stream, the value of the variable out, has been redirected to a file or other destination that is typically not continuously monitored.

::java::io::InputStream java::lang::System::in [static]

The "standard" input stream. This stream is already open and ready to supply input data. Typically this stream corresponds to keyboard input or another input source specified by the host environment or user.

::java::io::PrintStream java::lang::System::out [static]

The "standard" output stream. This stream is already open and ready to accept output data. Typically this stream corresponds to display output or another output destination specified by the host environment or user. For simple stand-alone Java applications, a typical way to write a line of output data is: <blockquote> System.out.println(data) </blockquote> See the println methods in class PrintStream.

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

• java_lang_System.h

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