Class Utilities

java.lang.Object

edu.uky.cs.nil.tt.Utilities

public class Utilities
extends Object

A collection of utility methods used throughout this project.

Author:

Stephen G. Ware

Method Summary

Modifier and Type	Method	Description
static final int	bits(int count)	Returns the number of bits needed to assign unique ID numbers to each of a given number of objects.
static final String	capitalize(String string)	Capitalizes the first letter of a string.
static final String	getRandomName()	Randomly generates a valid name.
static final void	requireAllNonNull(Object[] array, String description)	Throws an exception if any index in an array is null.
static final <T> T	requireEquals(T object, Object other)	Returns the first object if both objects are equal; otherwise, throws an exception.
static final void	requireExactly(long number, long value, String description)	Throws an exception if a given number is anything other than a specific value.
static final void	requireGreaterThan(long number, long lower, String description)	Throws an exception if a number is not greater than a given lower bound.
static final void	requireLessThanOrEqualTo(long number, long max, String description)	Throws an exception if a number is not less than or equal to a given upper bound.
static final void	requireName(String string)	Throws an exception if a string does not meet the requirements for a name.
static final void	requireNonNegative(long number, String description)	Throws an exception if a number is negative.
static final void	requireNonNull(Object object, String description)	Throws an exception if the given object is null.
static final <T> T	requireType(Object object, Class<T> type, String description)	If a given object is of the given type, this method casts the object to that type; otherwise, it throws an exception.
static final int	toInteger(String string)	Parses a string into an integer or throws an exception if the string cannot be parsed.

Methods inherited from class Object

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

Method Details

requireNonNull

public static final void requireNonNull(Object object,
 String description)

Throws an exception if the given object is null.

Parameters:

object - the object which should not be null

description - a short description of the type of object, used in the message of the exception which is thrown if the object is null

Throws:

NullPointerException - if the object given is null

requireAllNonNull

public static final void requireAllNonNull(Object[] array,
 String description)

Throws an exception if any index in an array is null.

Parameters:

array - the array of objects, none of which should be null

description - a short description of the type of object in the array, used in the message of the exception which is thrown if the object is null

Throws:

NullPointerException - if any index in the given array is null

requireType

public static final <T> T requireType(Object object,
 Class<T> type,
 String description)

If a given object is of the given type, this method casts the object to that type; otherwise, it throws an exception.

Type Parameters:

T - the type to which the object will be cast, if possible

Parameters:

object - the object to be cast

type - the class to which the object will be cast

description - a short description of the type of object to be cast, used in the message of the exception which is thrown if the object cannot be cast

Returns:

the object, cast to the given type

Throws:

IllegalArgumentException - if the given object is null or cannot be cast to the given type

requireEquals

public static final <T> T requireEquals(T object,
 Object other)

Returns the first object if both objects are equal; otherwise, throws an exception. This method can accept null arguments. If only one argument is null, the exception will be thrown, but if both arguments are null, no exception will be thrown.

Type Parameters:

T - the type of the first object

Parameters:

object - the first object

other - the second object

Returns:

the first object, if both objects are equal

Throws:

IllegalArgumentException - if the two objects are not equal

requireExactly

public static final void requireExactly(long number,
 long value,
 String description)

Throws an exception if a given number is anything other than a specific value.

Parameters:

number - the number which should be a specific value

value - the value that number should be

description - a short description of the purpose of the number, used in the message of the exception which is thrown if the number is not the correct value

Throws:

IllegalArgumentException - if the number is not the given value

requireNonNegative

public static final void requireNonNegative(long number,
 String description)

Throws an exception if a number is negative.

Parameters:

number - the number which should not be negative

description - a short description of the purpose of the number, used in the message of the exception which is thrown if the number is negative

requireGreaterThan

public static final void requireGreaterThan(long number,
 long lower,
 String description)

Throws an exception if a number is not greater than a given lower bound.

Parameters:

number - the number which must be greater than the lower bound

lower - the lower bound

description - a short description of the purpose of the number, used in the message of the exception which is thrown if the number is not greater than the lower bound

requireLessThanOrEqualTo

public static final void requireLessThanOrEqualTo(long number,
 long max,
 String description)

Throws an exception if a number is not less than or equal to a given upper bound.

Parameters:

number - the number which must be less than or equal to the upper bound

max - the upper bound

description - a short description of the purpose of the number, used in the message of the exception which is thrown if the number is not less than or equal to the upper bound

Throws:

IllegalArgumentException - if the number if not less than or equal to the given upper bound

requireName

public static final void requireName(String string)

Throws an exception if a string does not meet the requirements for a name. Requirements may include limits on length and the number of characters.

Parameters:

string - the string which must be a valid name

Throws:

IllegalArgumentException - if the string is not a valid name

bits

public static final int bits(int count)

Returns the number of bits needed to assign unique ID numbers to each of a given number of objects. If the given number of objects is 0 or 1, then 0 bits are needed. Two objects require 1 bit. Three or four objects require 2 bits, etc.

Parameters:

count - the number of objects which must each be assigned a unique ID number

Returns:

the minimum number of bits needed to assign a unique ID number to each of the given number of objects

capitalize

public static final String capitalize(String string)

Capitalizes the first letter of a string.

Parameters:

string - the string whose first letter should be a capital letter

Returns:

an identical string, except that the first letter has been capitalized

toInteger

public static final int toInteger(String string)

Parses a string into an integer or throws an exception if the string cannot be parsed.

Parameters:

string - the string to be parsed as an integer

Returns:

the integer

Throws:

NumberFormatException - if the string cannot be parsed as an integer

getRandomName

public static final String getRandomName()

Randomly generates a valid name.

Returns:

a random valid name