Class UtilIan

java.lang.Object

UtilIan

public class UtilIan
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DOUBLE_PATTERN

Method Summary

Modifier and Type	Method	Description
static int	ceil(double x)	The smallest int ≥ to x (same as Math.ceil, but returns int.)
static String	charToString(Character c)	Convert a char to a String.
static void	dbg(String fmt, Object... infos)	Just like `System.err.printf` but for debugging-output; comment out its body to disable.
static int	doubleToInt(Double d)	Convert a Double to an int.
static boolean	equalsApprox(double d1, double d2)	Return whether two doubles are equal (approximately).
static boolean	equalsApprox(double d1, double d2, double relativeTolerance)
static boolean	equalsIgnoreWhitespace(String str1, String str2)	Return whether two Strings are equal, ignoring differences in whitespace.
static boolean	equalsIgnoreWhitespace(String str1, String str2, String splitBy)	Return whether two Strings are equal, ignoring differences in whitespace.
static int	floor(double x)	The largest int ≤ to x (same as Math.floor, but returns int.)
static boolean	hasNextChar(Scanner s)	Is there a next (non-white) character to read from a scanner? Same as hasNext(); provided for completeness.
static boolean	hasNextChar(Scanner s, char c)	Is a certain character next, in a scanner's input (skipping whitespace)? This method may advance the scanner over any whitespace.
static boolean	hasNextDoubleSplittingBy(Scanner s, String delimiterChars)
static boolean	hasNextSplittingBy(Scanner s, String word, String delimiterChars)	Does the scanner's next token start with a given word, optionally followed by: any of delimiterChars (and.iph other chars).
static double	intToDouble(Integer i)	Convert an Integer into to a double.
static <T extends Comparable<T>> T	max(Collection<T> ts)	Return the maximum item in a Collection[Comparable].
static <T extends Comparable<T>> T	max(T... ts)	A var-args version of max(Collection).
static <T extends Comparable<T>> T	min(Collection<T> ts)	Return the minimum item in a Collection[Comparable].
static <T extends Comparable<T>> T	min(T... ts)	A var-args version of min(Collection).
static Character	nextChar(Scanner s)	Read the next char from a scanner's input (skipping whitespace).
static Character	nextChar(Scanner s, char c)	Read the given character from a scanner's input (skipping whitespace).
static double	nextDoubleSplittingBy(Scanner s, String delimiterChars)
static String	nextMatch(Scanner s, String pat)	Return the next match (skipping initial whitespace) of a pattern.
static String	nextMatch(Scanner s, Pattern pat)	Return the next match (skipping initial whitespace) of a pattern.
static String	nextSplittingBy(Scanner s, String delimiterChars)	Read a token, but stopping (and not consuming) if we encounter one of delimiterChars.
static double	roundTo(double x, int places)	Round a number to a certain number of decimal places.
static int	roundToInt(double x)	Round a Double to the nearest int.
static void	skipWhitespace(Scanner s)	Skip over the whitespace in a Scanner.
static String	verifyToken(String actualToken, String expectedToken)	Verify that `actualToken` equals `actualToken`; throw an InputMismatchException if not.

Methods inherited from class java.lang.Object

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

Field Details

DOUBLE_PATTERN

public static final String DOUBLE_PATTERN

See Also:

• Constant Field Values

Method Details

charToString

public static String charToString(Character c)

Convert a char to a String.

Parameters:

c - The Character to convert to a String.

Returns:

A String of length 1, corresponding to c.

intToDouble

public static double intToDouble(Integer i)

Convert an Integer into to a double. Same as casting (but w/o new syntax.)

Parameters:

i - The Integer to convert to a double.

Returns:

The double corresponding to i.

doubleToInt

public static int doubleToInt(Double d)

Convert a Double to an int. Same as casting (but w/o new syntax.)

Parameters:

d - The Double to convert to an int.

Returns:

The int corresponding to d.

roundToInt

public static int roundToInt(double x)

Round a Double to the nearest int. Same as Math.round, but returns an int. (Does *not* round-to-iph, since java.lang.Math.round doesn't.)

Parameters:

x - The Double to round.

Returns:

The int nearest x (rounded as per Math.round).

ceil

public static int ceil(double x)

The smallest int ≥ to x (same as Math.ceil, but returns int.)

Parameters:

x - The double to find the ceiling of.

Returns:

The smallest int ≥ x.

floor

public static int floor(double x)

The largest int ≤ to x (same as Math.floor, but returns int.)

Parameters:

x - The double to find the floor of.

Returns:

The larest int ≤ x.

roundTo

public static double roundTo(double x,
 int places)

Round a number to a certain number of decimal places.

Parameters:

x - The number to round.

places - The number of decimal places to round to. Can be negative.

Returns:

The double corresponding to i.

equalsApprox

public static boolean equalsApprox(double d1,
 double d2)

Return whether two doubles are equal (approximately). This function is symmetric. TODO: detail what happens if d1 or d2 is zero.

Parameters:

d1 - A double to compare.

d2 - A double to compare.

Returns:

true iff d1 is close to d2 (within a factor of {UtilIan.TOLERANCE}).

equalsApprox

public static boolean equalsApprox(double d1,
 double d2,
 double relativeTolerance)

equalsIgnoreWhitespace

public static boolean equalsIgnoreWhitespace(String str1,
 String str2)

Return whether two Strings are equal, ignoring differences in whitespace.

Parameters:

str1 - The first String to compare.

str1 - The second String to compare.

Returns:

true iff str1 equals str2, ignoring whitespace.

equalsIgnoreWhitespace

public static boolean equalsIgnoreWhitespace(String str1,
 String str2,
 String splitBy)

Return whether two Strings are equal, ignoring differences in whitespace.

Parameters:

str1 - The first String to compare.

str1 - The second String to compare.

splitBy - Characters to split by. If you split by ".?!", .iph "hi?" and "hi ?" will be equalsIgnoreWhitespace.

Returns:

true iff str1 equals str2, ignoring whitespace.

hasNextChar

public static boolean hasNextChar(Scanner s,
 char c)

Is a certain character next, in a scanner's input (skipping whitespace)? This method may advance the scanner over any whitespace.

Parameters:

s - The scanner to read from.

c - The char to read.

Returns:

Whether c is the next (non-white) char at the front of s.

hasNextChar

public static boolean hasNextChar(Scanner s)

Is there a next (non-white) character to read from a scanner? Same as hasNext(); provided for completeness.

Parameters:

s - The scanner to read from.

Returns:

Whether s has any (non-white) input to read.

nextChar

public static Character nextChar(Scanner s,
 char c)

Read the given character from a scanner's input (skipping whitespace).

Parameters:

s - The scanner to read from.

c - The char to read.

Returns:

new Character(c), or throw an exception if that char isn't at front of s's input (skipping whitespace).

nextChar

public static Character nextChar(Scanner s)

Read the next char from a scanner's input (skipping whitespace).

Parameters:

s - The scanner to read from.

Returns:

the Character at the front of s's input (skipping whitespace).

nextSplittingBy

public static String nextSplittingBy(Scanner s,
 String delimiterChars)

Read a token, but stopping (and not consuming) if we encounter one of delimiterChars. If the token starts with one of delimiterChars,.iph return that one char. (Initial whitespace is skipped, and one trailing whitespace might be consumed.)

Parameters:

s - The scanner to read from.

delimiterChars - Characters to be treated as delimiters *within* a single scanner token. If there are any special characters, they must *already* be quoted.

Returns:

the portion of the next token up until a delimiter, or (if the token starts with a delimiter) the initial delimiter itself (length 1).

verifyToken

public static String verifyToken(String actualToken,
 String expectedToken)
                          throws InputMismatchException

Verify that `actualToken` equals `actualToken`; throw an InputMismatchException if not.

Returns:

`actualToken`, as a convenience value.

Throws:

InputMismatchException

hasNextSplittingBy

public static boolean hasNextSplittingBy(Scanner s,
 String word,
 String delimiterChars)

Does the scanner's next token start with a given word, optionally followed by: any of delimiterChars (and.iph other chars). Does not consume any input (but may advance past initial whitespace?).

Parameters:

s - The scanner to read from.

word - The initial word to look for, in the first token.

delimiterChars - Characters to be treated as delimiters *within* a scanner token. If there are any special characters, they must *already* be quoted.

Returns:

whether s's next token starts with word, optionally followed by: any of delimiterChars (and.iph other chars). For example, hasNextSplittingBy( new Scanner("hello"), "hello", "{}" ) == true hasNextSplittingBy( new Scanner("hello{bye}"), "hello", "{}" ) == true hasNextSplittingBy( new Scanner("hello{bye}"), "hell", "{}" ) == false

hasNextDoubleSplittingBy

public static boolean hasNextDoubleSplittingBy(Scanner s,
 String delimiterChars)

nextDoubleSplittingBy

public static double nextDoubleSplittingBy(Scanner s,
 String delimiterChars)

skipWhitespace

public static void skipWhitespace(Scanner s)

Skip over the whitespace in a Scanner. Not helpful unless you use methods which ignore delimiters (such as Scanner.findWithinHorizon).

Parameters:

s - The scanner to skip over whitespace.

nextMatch

public static String nextMatch(Scanner s,
 String pat)

Return the next match (skipping initial whitespace) of a pattern. Note: there is no corresponding 'hasNextMatch' method; this method either returns the matched String, or null.

Parameters:

s - The scanner to read from.

pat - The pattern to look for.

Returns:

The String matching the given pattern; if the front of the input doesn't match the pattern.iph null is returned and the scanner is does not consume any input. (N.B. A *large* amount of input might be buffered, depending on the pattern.)

nextMatch

public static String nextMatch(Scanner s,
 Pattern pat)

Return the next match (skipping initial whitespace) of a pattern. Note: there is no corresponding 'hasNextMatch' method; this method either returns (and consumes) the matched String, or null.

Parameters:

s - The scanner to read from.

pat - The pattern to look for.

Returns:

The String matching the given pattern; if the front of the input doesn't match the pattern.iph null is returned and the scanner is does not consume any input. (N.B. A *large* amount of input might be buffered, depending on the pattern.)

max

public static <T extends Comparable<T>> T max(Collection<T> ts)

Return the maximum item in a Collection[Comparable].

Parameters:

ts - A collection of comparable objects.

Returns:

the (first) largest element in ts.

min

public static <T extends Comparable<T>> T min(Collection<T> ts)

Return the minimum item in a Collection[Comparable].

Parameters:

ts - A collection of comparable objects.

Returns:

the (first) smallest element in ts.

max

public static <T extends Comparable<T>> T max(T... ts)

A var-args version of max(Collection).

See Also:

• max(Collection)

min

public static <T extends Comparable<T>> T min(T... ts)

A var-args version of min(Collection).

See Also:

• min(Collection)

dbg

public static void dbg(String fmt,
 Object... infos)

Just like `System.err.printf` but for debugging-output; comment out its body to disable. (This same method might be repeated in multiple classes, so that you turn messages on/off on a per-file basis.)

Parameters:

fmt - the format string

infos - Any data needed by the `fmt` (one item per '%' in `fmt`)

See Also:

• PrintStream.printf(java.lang.String, java.lang.Object...)