boone.util

Class Common

java.lang.Object

boone.util.Common

public class Common
extends java.lang.Object

A collection of commonly useful methods.

Version:

$Id$

Author:

Helmut A. Mayer

Field Summary

Fields

Modifier and Type	Field and Description
static java.text.DecimalFormat	fixedPoint For numbers with four fraction digits.
static java.util.Random	random The common RNG.
static java.text.DecimalFormat	scientific For numbers in a power format.

Constructor Summary

Constructors

Constructor and Description
Common()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	appendExtension(java.lang.String fileName, java.lang.String defaultExtension) Add a file extension, if the file name doesn't yet have one.
static <E> java.util.List<E>	asList(E[] a) Returns the array elements in list form.
static java.lang.String	cutHeadAtLast(java.lang.String terms, char c) Eliminates the substring before the last occurrence of 'c' including 'c'.
static java.lang.String	cutLeadChar(java.lang.String s, char c) Eliminates the potential leading char 'c' in string 's'.
static java.lang.String	cutTailAtLast(java.lang.String terms, char c) Eliminates the substring after the last occurrence of 'c' including 'c'.
static double	getDuration(double timeStamp) Returns the time passed since the given time stamp.
static int	getMaxIndex(double[] values) Returns the index of the max value of an array.
static int	getMaxIndex(java.util.List<java.lang.Double> values) Returns the index of the max value of a Double list.
static java.util.Random	getRandom() Returns the common random number generator.
static double	getRandom(double low, double high) Returns a random value from the interval [low, high).
static char	getSeparatorChar(java.lang.String s) Determines the separator character in a given string.
static double	getTimeStamp() Returns the current time stamp in milli-seconds.
static boolean	inRange(int val, int low, int high) Checks if the given value is in the given range.
static double	limitToRange(double val, double low, double high) Limits a value to the given boundaries.
static <E> void	replace(java.util.List<E> list, E a, E b) Replaces element a with element b in the list.
static java.lang.String	stripOff(java.lang.String s, char c) Strips off all characters 'c' in string 's'.
static <E> void	swap(java.util.List<E> l, int a, int b) Swaps the objects at the given positions in the list.

Methods inherited from class java.lang.Object

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

Field Detail

random

public static java.util.Random random

The common RNG.

fixedPoint

public static java.text.DecimalFormat fixedPoint

For numbers with four fraction digits.

scientific

public static java.text.DecimalFormat scientific

For numbers in a power format.

Constructor Detail

Common

public Common()

Method Detail

getMaxIndex

public static int getMaxIndex(double[] values)

Returns the index of the max value of an array.

Parameters:

values - the array

Returns:

the max index

getMaxIndex

public static int getMaxIndex(java.util.List<java.lang.Double> values)

Returns the index of the max value of a Double list.

Parameters:

values - the array

Returns:

the max index

getTimeStamp

public static double getTimeStamp()

Returns the current time stamp in milli-seconds.

getDuration

public static double getDuration(double timeStamp)

Returns the time passed since the given time stamp.

Parameters:

timeStamp - a time stamp in milliseconds

Returns:

duration in seconds

limitToRange

public static double limitToRange(double val,
                                  double low,
                                  double high)

Limits a value to the given boundaries.

Parameters:

val - a value

low - lower boundary

high - upper boundary

inRange

public static boolean inRange(int val,
                              int low,
                              int high)

Checks if the given value is in the given range.

Parameters:

val - a value

low - lower boundary (included)

high - upper boundary (excluded)

getRandom

public static java.util.Random getRandom()

Returns the common random number generator.

getRandom

public static double getRandom(double low,
                               double high)

Returns a random value from the interval [low, high).

Parameters:

low - the lower bound (included)

high - the upper bound (excluded)

Returns:

a random value within the given bounds

cutHeadAtLast

public static java.lang.String cutHeadAtLast(java.lang.String terms,
                                             char c)

Eliminates the substring before the last occurrence of 'c' including 'c'.

Parameters:

terms - a string

c - the delimiting character

Returns:

a new cut string

cutTailAtLast

public static java.lang.String cutTailAtLast(java.lang.String terms,
                                             char c)

Eliminates the substring after the last occurrence of 'c' including 'c'.

Parameters:

c - the delimiting character

terms - a String

Returns:

a new cut String

cutLeadChar

public static java.lang.String cutLeadChar(java.lang.String s,
                                           char c)

Eliminates the potential leading char 'c' in string 's'.

Parameters:

c - the possibly leading character

s - a string

Returns:

string without leading char, or unchanged string (if 'c' is not leading char)

stripOff

public static java.lang.String stripOff(java.lang.String s,
                                        char c)

Strips off all characters 'c' in string 's'. E.g., stripOff("Peter", 'e') returns "Ptr".

Parameters:

c - the character to be erased

s - a string

Returns:

a new string with all 'c's stripped off

getSeparatorChar

public static char getSeparatorChar(java.lang.String s)

Determines the separator character in a given string. The string is searched for a) the system-dependent separator (which may be '\\' in case of Windows), and if not found then b) it is searched for the separator used in JAR files. If none of these is found, 0 is returned.

Parameters:

s - a string containing separators

Returns:

the separating character, 0 if none of the searched found

asList

public static <E> java.util.List<E> asList(E[] a)

Returns the array elements in list form.

Parameters:

a - an array

Returns:

a list

replace

public static <E> void replace(java.util.List<E> list,
                               E a,
                               E b)

Replaces element a with element b in the list.

Parameters:

list - a list

a - element to be replaced

b - element to be inserted

swap

public static <E> void swap(java.util.List<E> l,
                            int a,
                            int b)

Swaps the objects at the given positions in the list.

Parameters:

l - a list

a - index of object A

b - index of object B

appendExtension

public static java.lang.String appendExtension(java.lang.String fileName,
                                               java.lang.String defaultExtension)

Add a file extension, if the file name doesn't yet have one. Extensions follow the actual file title and are separated by a dot. They are of arbitrary size (Java for DOS, anyone? :).

If the file name is fully enclosed in double quotes ("), remove them, but don't append an extension.
If the file name already has another extension, don't change it.
If the filename only consists of a path, too bad; ext is appended anyway.

Also, ignore path elements that precede the file name.

Parameters:

fileName - The file name to append the extension to.

defaultExtension - The extension to add, if necessary.

Returns:

The file name, with the extension appended, if appropriate.