Package blbutil

Class Utilities

java.lang.Object

blbutil.Utilities

public class Utilities
extends java.lang.Object

Class Utilities contains miscellaneous static utility methods.

Method Summary

Modifier and Type	Method	Description
static java.lang.String	commandLine(java.lang.String program, java.lang.String[] args)	Returns a string representation of the command line arguments.
static void	duoPrint(java.io.PrintWriter out, java.lang.CharSequence s)	Prints the specified string to the specified PrintWriter and to standard out.
static void	duoPrintln(java.io.PrintWriter out, java.lang.CharSequence s)	Prints the specified string to the specified PrintWriter and to standard out.
static java.lang.String	elapsedNanos(long nanoseconds)	Returns a string representation of the specified elapsed time in the format "H hours M minutes S seconds".
static void	exit(java.lang.String s)	Prints the specified string to standard error and then terminates the Java virtual machine.
static void	exit(java.lang.String s, java.lang.Throwable t)	Prints the specified exception, its stack trace, and the specified string to standard error and then terminates the Java virtual machine.
static void	exit(java.lang.Throwable t)	Prints the specified exception, its stack trace, and the specified string to standard error and then terminates the Java virtual machine.
static java.util.Set<java.lang.String>	idSet(java.io.File file)	Returns a set of identifiers found in a text file that has one identifier per line.
static java.lang.String	minutesAndSeconds()	Returns the current minutes and seconds as a string.
static void	printMemoryUse(java.lang.String msg)	Prints a summary of memory use at the time of method invocation to standard output.
static void	shuffle(int[] ia, int nElements, java.util.Random random)	Shuffles the specified array so that a random set of ${code nElements} from the array are the first elements.
static void	shuffle(int[] ia, java.util.Random random)	Randomly shuffles the elements of the specified array.
static java.lang.String	timeStamp()	Returns the current local time as a string.

Methods inherited from class java.lang.Object

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

Method Detail

commandLine

public static java.lang.String commandLine(java.lang.String program,
                                           java.lang.String[] args)

Returns a string representation of the command line arguments. The exact details of the representation are unspecified and subject to change.

Parameters:

program - the name of the program's jar file.

args - command line arguments.

Returns:

a string representation of the command line arguments.

printMemoryUse

public static void printMemoryUse(java.lang.String msg)

Prints a summary of memory use at the time of method invocation to standard output.

Parameters:

msg - a string a message to be printed with the summary of memory use

timeStamp

public static java.lang.String timeStamp()

Returns the current local time as a string. The exact details of the string representation are unspecified and subject to change.

Returns:

the current local time as a string.

minutesAndSeconds

public static java.lang.String minutesAndSeconds()

Returns the current minutes and seconds as a string. The exact details of the string representation are unspecified and subject to change.

Returns:

the current local time as a string.

idSet

public static java.util.Set<java.lang.String> idSet(java.io.File file)

Returns a set of identifiers found in a text file that has one identifier per line. The empty set is returned if file == null. Blank lines are ignored, and white-space that begins or ends a line is ignored.

If an IOException is thrown, an error message is printed to standard error and the Java virtual machine is forced to terminate.

Parameters:

file - a text file with one identifier per line

Returns:

a set of identifiers

Throws:

java.lang.IllegalArgumentException - if the specified file does not exist

java.lang.IllegalArgumentException - if the specified file is a directory

java.lang.IllegalArgumentException - if any line of the specified file contains two non-white-space characters separated by one or more white-space characters

duoPrint

public static void duoPrint(java.io.PrintWriter out,
                            java.lang.CharSequence s)

Prints the specified string to the specified PrintWriter and to standard out. The line separator string is not appended to the specified string before printing.

Parameters:

out - a print writer

s - a string to be printed

Throws:

java.lang.NullPointerException - if out == null

duoPrintln

public static void duoPrintln(java.io.PrintWriter out,
                              java.lang.CharSequence s)

Prints the specified string to the specified PrintWriter and to standard out. The line separator string is appended to the specified string before printing.

Parameters:

out - a print writer

s - a string to be printed

Throws:

java.lang.NullPointerException - if out == null

elapsedNanos

public static java.lang.String elapsedNanos(long nanoseconds)

Returns a string representation of the specified elapsed time in the format "H hours M minutes S seconds".

Parameters:

nanoseconds - the elapsed time in nanoseconds

Returns:

a string representation of the specified elapsed time

exit

public static void exit(java.lang.String s,
                        java.lang.Throwable t)

Prints the specified exception, its stack trace, and the specified string to standard error and then terminates the Java virtual machine.

Parameters:

s - a string to be printed to standard error

t - an exception or error to be printed to standard error

Throws:

java.lang.NullPointerException - if e == null

exit

public static void exit(java.lang.Throwable t)

Prints the specified exception, its stack trace, and the specified string to standard error and then terminates the Java virtual machine.

Parameters:

t - an exception or error to be printed to standard error

Throws:

java.lang.NullPointerException - if e == null

exit

public static void exit(java.lang.String s)

Prints the specified string to standard error and then terminates the Java virtual machine.

Parameters:

s - a string to be written to standard error

shuffle

public static void shuffle(int[] ia,
                           java.util.Random random)

Randomly shuffles the elements of the specified array.

Parameters:

ia - an array to be shuffled

random - a random number generator

Throws:

java.lang.NullPointerException - if ia == null || random == null

shuffle

public static void shuffle(int[] ia,
                           int nElements,
                           java.util.Random random)

Shuffles the specified array so that a random set of ${code nElements} from the array are the first elements. The specified array is unchanged if nElements <= 0.

Parameters:

ia - an array to be shuffled

nElements - the size of the random set of elements which are shuffled to the beginning of the array

random - a random number generator

Throws:

java.lang.IndexOutOfBoundsException - if nElements > ia.length

java.lang.NullPointerException - if ia == null || random == null