Package blbutil

Class Utilities

  • public class Utilities
extends java.lang.Object
    Class Utilities contains miscellaneous static utility methods.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      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()
      Prints "Terminating program." to standard error and terminates the Java virtual machine.
      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.Throwable t)
      Prints the specified exception, its stack trace and then terminates the Java virtual machine.
      static void exit​(java.lang.Throwable thr, java.lang.String str)
      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} elements from the array are the first ${code nElements} 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.Throwable thr,
                        java.lang.String str)
        Prints the specified exception, its stack trace, and the specified string to standard error and then terminates the Java virtual machine.
        Parameters:
        str - a string to be printed to standard error
        thr - an exception or error to be printed to standard error
        Throws:
        java.lang.NullPointerException - if t == null

      • exit

        public static void exit​(java.lang.Throwable t)
        Prints the specified exception, its stack trace 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

      • exit

        public static void exit()
        Prints "Terminating program." to standard error and terminates the Java virtual machine.

      • 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} elements from the array are the first ${code nElements} 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