Package org.refcodes.runtime

Class SystemUtility

java.lang.Object

org.refcodes.runtime.SystemUtility

public final class SystemUtility
extends Object

Utility for acquiring system information on the machine this process is running in.

Method Summary

Modifier and Type	Method	Description
static String	exec(String aCommand)	Executes a command and returns the output.
static String	getComputerName()	Determines the computer's name.
static String	getLineBreak()	Determines the operating system as of OperatingSystem.toOperatingSystem() and in case a OperatingSystem.WINDOWS is being detected, then \r\n" (CRLF) is returned, else "\n" (LF) is returned.
static String	getSystemEncoding()	Determines the encoding of the system (system's console) in use as of System.out.
static File	getTempDir()	Returns the operating saystem's temp folder.
static int	getTerminalHeight()	Determines the height in characters of the system's terminal in use.
static int	getTerminalWidth()	Determines the width in characters of the system's terminal in use.
static String	getUname()	If on a *nix alike system, this method returns the output of the "uname -a" command: "uname" prints system information, "-a" instructs it to print all information.
static boolean	isAnsiConsole()	Determines whether ANSI escape sequences are forced to be supported or not by REFCODES.ORG artifacts.
static boolean	isAnsiTerminal()	Determines whether ANSI escape sequences are supported by the terminal.
static boolean	isUseLineBreak(int aRowWidth)	Determines whether wee need an explicit line-break for the given width on the current operating system and used terminal.
static int	toAnsiconHeight(String aAnsiconEnvVarValue)	Extracts the height from an "ANSICON" environment variable's value.
static int	toAnsiconWidth(String aAnsiconEnvVarValue)	Extracts the width from an "ANSICON" environment variable's value.
static int	toConsoleHeight()	Does some calculation to always return a sound console height (never returns -1).
static int	toConsoleWidth()	Does some calculation to always return a sound console width (never returns -1).
static byte[]	toHostIpAddress()	Tries to determine a no-localhost IP-Address for this machine.
static byte[]	toHostMacAddress()	Tries to determine the host Mac-Address for this machine.
static String	toLineBreak(int aRowWidth)	Uses isUseLineBreak(int) to retrieve the character sequence required to suffix to a line in order to get a line break without risking any empty lines as of automatic line wrapping.
static String	toPrettySystemInfo()	Gathers all available system information from this Artifac's point of view.
static String	toPropertyValue(String aDefaultValue, org.refcodes.data.SystemProperty aSystemProperty, org.refcodes.data.EnvironmentVariable... aEnvironmentProperties)	Gets the value for the provided properties, if non was found then the default value is taken.
static String	toPropertyValue(org.refcodes.data.SystemProperty aSystemProperty, org.refcodes.data.EnvironmentVariable... aEnvironmentProperties)	Gets the value for the provided properties, if non was found then null is returned.
static Map<String,String>	toSystemInfo()	Gathers all available system information from this Artifac's point of view.

Methods inherited from class java.lang.Object

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

Method Detail

getLineBreak

public static String getLineBreak()

Determines the operating system as of OperatingSystem.toOperatingSystem() and in case a OperatingSystem.WINDOWS is being detected, then \r\n" (CRLF) is returned, else "\n" (LF) is returned. Can be overridden with the SystemProperty.CONSOLE_LINE_BREAK (java -Dconsole.lineBreak=...) and the EnvironmentVariable.CONSOLE_LINE_BREAK ("export CONSOLE_LINE_BREAK=...).

Returns:

The operating system's specific line break; on Windows it is "\r\n" (CRLF) and on all other operating systems it is "\n" (LF).

isUseLineBreak

public static boolean isUseLineBreak(int aRowWidth)

Determines whether wee need an explicit line-break for the given width on the current operating system and used terminal. E.g. on "win.cmd" we must not use a line-break in case our line is a s long as the console's width. There are some more such cases which this method tries to take into consideration.

Parameters:

aRowWidth - The row width you want to use when printing out to a console.

Returns:

True in case you should use a line-break.

toLineBreak

public static String toLineBreak(int aRowWidth)

Uses isUseLineBreak(int) to retrieve the character sequence required to suffix to a line in order to get a line break without risking any empty lines as of automatic line wrapping. Automatic line wrapping can happen on Windows environment when the console width is reached. A line break would cause a superfluous empty line (ugly).

Parameters:

aRowWidth - The row width you want to use when printing out to a console.

Returns:

The system's line break characters when a line break is emphasized or an empty string if no line break sequence is recommended.

getComputerName

public static String getComputerName()

Determines the computer's name. First it tries to get it from the InetAddress, if it fails it tries to get it from the system's environment using the EnvironmentVariable.COMPUTERNAME (on Windows machines only) and if both fails, it returns the default Literal.LOCALHOST identifier.

Returns:

The computer's name, as fallback, Literal.LOCALHOST ("localhost") is returned.

getUname

public static String getUname()

If on a *nix alike system, this method returns the output of the "uname -a" command: "uname" prints system information, "-a" instructs it to print all information.

Returns:

The "uname -a" output or null if "uname" is not known.

getTerminalWidth

public static int getTerminalWidth()

Determines the width in characters of the system's terminal in use.

Returns:

The width of the terminal in characters or -1 if the width cannot be determined.

getTerminalHeight

public static int getTerminalHeight()

Determines the height in characters of the system's terminal in use.

Returns:

The height of the terminal in characters or -1 if the height cannot be determined.

toAnsiconWidth

public static int toAnsiconWidth(String aAnsiconEnvVarValue)
                          throws NumberFormatException

Extracts the width from an "ANSICON" environment variable's value.

Parameters:

aAnsiconEnvVarValue - The "ANSICON" formatted variable (e.g. "91x19999 (91x51)").

Returns:

The determined width.

Throws:

NumberFormatException - Thrown in case no width was determinable from the provided value.

toAnsiconHeight

public static int toAnsiconHeight(String aAnsiconEnvVarValue)
                           throws NumberFormatException

Extracts the height from an "ANSICON" environment variable's value.

Parameters:

aAnsiconEnvVarValue - The "ANSICON" formatted variable (e.g. "91x19999 (91x51)").

Returns:

The determined height.

Throws:

NumberFormatException - Thrown in case no width was determinable from the provided value.

toConsoleWidth

public static int toConsoleWidth()

Does some calculation to always return a sound console width (never returns -1). Anything in the REFCODES.ORG artifacts which is intended to print to the console uses this method to determine some heuristic best console width.

Returns:

A sound heuristic console width.

toConsoleHeight

public static int toConsoleHeight()

Does some calculation to always return a sound console height (never returns -1). Anything in the REFCODES.ORG artifacts which is intended to print to the console uses this method to determine some heuristic best console height.

Returns:

A sound heuristic console height.

toPropertyValue

public static String toPropertyValue(String aDefaultValue,
                                     org.refcodes.data.SystemProperty aSystemProperty,
                                     org.refcodes.data.EnvironmentVariable... aEnvironmentProperties)

Gets the value for the provided properties, if non was found then the default value is taken. A SystemProperty elements wins over the EnvironmentVariable elements. The preceding EnvironmentVariable element wins over the succeeding EnvironmentVariable element. The default value is taken if non property had a value (a String with length > 0).

Parameters:

aDefaultValue - The default value to take when none other value was set.

aSystemProperty - The system-property passed via java -D<name>=<value>

aEnvironmentProperties - The properties looked for in the system's environment variables.

Returns:

The best fitting value.

toPropertyValue

public static String toPropertyValue(org.refcodes.data.SystemProperty aSystemProperty,
                                     org.refcodes.data.EnvironmentVariable... aEnvironmentProperties)

Gets the value for the provided properties, if non was found then null is returned. A SystemProperty elements wins over the EnvironmentVariable elements. The preceding EnvironmentVariable element wins over the succeeding EnvironmentVariable element. A null is taken if non property had a value (a String with length > 0).

Parameters:

aSystemProperty - The system-property passed via java -D<name>=<value>

aEnvironmentProperties - The properties looked for in the system's environment variables.

Returns:

The best fitting value or null if none was detected.

exec

public static String exec(String aCommand)
                   throws IOException,
                          InterruptedException

Executes a command and returns the output.

Parameters:

aCommand - the command

Returns:

Null if execution failed, else the according output. An empty String stands fur successful execution.

Throws:

IOException - in case there were problems executing the command.

InterruptedException - thrown in case execution as been interrupted.

isAnsiTerminal

public static boolean isAnsiTerminal()

Determines whether ANSI escape sequences are supported by the terminal.

Returns:

True in case ANSI escape sequences are supported, else false.

isAnsiConsole

public static boolean isAnsiConsole()

Determines whether ANSI escape sequences are forced to be supported or not by REFCODES.ORG artifacts. This overrules isAnsiTerminal() for the REFCODES.ORG artifacts. Various settings such as SystemProperty.CONSOLE_ANSI and (in this order) EnvironmentVariable.CONSOLE_ANSI overrule isAnsiTerminal().

Returns:

True in case ANSI escape sequences are forced to be used by REFCODES.ORG artifacts or not.

getTempDir

public static File getTempDir()

Returns the operating saystem's temp folder.

Returns:

The folder used by the OS for storing temporary files.

getSystemEncoding

public static String getSystemEncoding()

Determines the encoding of the system (system's console) in use as of System.out.

Returns:

The encoding (of the console).

toSystemInfo

public static Map<String,String> toSystemInfo()

Gathers all available system information from this Artifac's point of view.

Returns:

A Map containing the available information being gathered.

toPrettySystemInfo

public static String toPrettySystemInfo()

Gathers all available system information from this Artifac's point of view. This method may rely on the output of toSystemInfo().

Returns:

A String containing the available information being gathered.

toHostIpAddress

public static byte[] toHostIpAddress()
                              throws SocketException,
                                     UnknownHostException

Tries to determine a no-localhost IP-Address for this machine. The best guess is returned. If none no-localhost address is found, then the localhost's IP-Address may be returned (as of InetAddress.getLocalHost()).

Returns:

The best guest for a no-localhost IP-Address or as a fall back the localhost's IP-Address (as of InetAddress.getLocalHost() may be returned.

Throws:

SocketException - Thrown to indicate that accessing the network interfaces caused a problem.

UnknownHostException - Thrown to indicate that the IP address of the local host could not be determined.

toHostMacAddress

public static byte[] toHostMacAddress()
                               throws SocketException,
                                      UnknownHostException

Tries to determine the host Mac-Address for this machine. The best guess is returned.

Returns:

The best guest for a Mac-Address is returned.

Throws:

SocketException - Thrown to indicate that accessing the network interfaces caused a problem.

UnknownHostException - Thrown to indicate that the IP address of the local host could not be determined.