Package it.unive.lisa.util.datastructures.regex

Class Star

java.lang.Object

it.unive.lisa.util.datastructures.regex.RegularExpression

it.unive.lisa.util.datastructures.regex.Star

All Implemented Interfaces:

TransitionSymbol<RegularExpression>, java.lang.Comparable<RegularExpression>

public final class Star
extends RegularExpression

A RegularExpression representing a loop, repeated an arbitrary number of times, over an inner regular expression.

Nested Class Summary

Nested classes/interfaces inherited from class it.unive.lisa.util.datastructures.regex.RegularExpression

RegularExpression.PartialSubstring

Field Summary

Fields inherited from interface it.unive.lisa.util.datastructures.automaton.TransitionSymbol

EPSILON, UNKNOWN_SYMBOL

Constructor Summary

Constructors

Constructor	Description
Star(RegularExpression op)	Builds the star.

Method Summary

Modifier and Type	Method	Description
protected int	compareToAux(RegularExpression other)	Auxiliary RegularExpression.compareTo(RegularExpression) that can safely assume that other is an object of the same class as this.
boolean	contains(java.lang.String s)	Yields true if and only if this regular expression always contains the given string.
boolean	endsWith(java.lang.String s)	Yields true if and only if this regular expression always ends with the given string.
boolean	equals(java.lang.Object obj)
RegularExpression[]	explode()	Yields a new regular expression that is the exploded version of this one, that is, where all atoms have been broken down to the composition of the characters that compose their inner strings.
RegularExpression	getOperand()	Yields the inner regular expression.
int	hashCode()
boolean	is(java.lang.String str)	Yields true if and only if this regular expression corresponds to the given string.
boolean	isEmpty()	Yields true if and only if this regular expression corresponds to the empty string or to no strings at all.
int	maxLength()	Yields the maximum length of this symbol.
boolean	mayContain(java.lang.String s)	Yields true if and only if this regular expression may contain the given string.
boolean	mayEndWith(java.lang.String s)	Yields true if and only if this regular expression may end with the given string.
boolean	mayStartWith(java.lang.String s)	Yields true if and only if this regular expression may start with the given string.
int	minLength()	Yields the minimum length of this symbol.
protected boolean	readsWhiteSpaceString()	Checks whether this regular expression recognize a string made just of whitespaces.
RegularExpression	repeat(long n)	Yields a new regular expression corresponding to the n-repetition of this.
RegularExpression	reverse()	Yields a new symbol that corresponds to this one, but read back-to-front.
RegularExpression	simplify()	Yields a simplified version of this regular expression.
boolean	startsWith(java.lang.String s)	Yields true if and only if this regular expression always starts with the given string.
java.util.Set<RegularExpression.PartialSubstring>	substringAux(int charsToSkip, int missingChars)	Returns the set of all possible substrings of this regular expression, starting at the given index (inclusive) and ending at the given index (exclusive).
<A extends Automaton<A,T>,T extends TransitionSymbol<T>> A	toAutomaton(AutomataFactory<A,T> factory)	Transforms this regular expression into its equivalent automaton.
protected RegularExpression	topAsEmptyString()	Yields a new regular expression where all TopAtom are assumed to have length zero.
protected RegularExpression	topAsSingleChar()	Yields a new regular expression where all TopAtom are assumed to have length one.
java.lang.String	toString()
RegularExpression	trimLeft()	Yields a new regular expression where leading whitespaces have been removed from this.
RegularExpression	trimRight()	Yields a new regular expression where trailing whitespaces have been removed from this.
protected RegularExpression	unrollStarToFixedLength(int length)	Yields a new regular expression where all Star have been unrolled to a sequence of their inner regular expression of length length.

Methods inherited from class it.unive.lisa.util.datastructures.regex.RegularExpression

asAtom, asComp, asEmptySet, asOr, asStar, comp, compareTo, isAtom, isComp, isEmptySet, isEpsilon, isOr, isStar, or, star, substring

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Star

public Star(RegularExpression op)

Builds the star.

Parameters:

op - the inner regular expression

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getOperand

public RegularExpression getOperand()

Yields the inner regular expression.

Returns:

the inner regular expression

simplify

public RegularExpression simplify()

Description copied from class: RegularExpression

Yields a simplified version of this regular expression. Simplification happens through heuristics.

Specified by:

simplify in class RegularExpression

Returns:

a simplified regular expression equivalent to this

toAutomaton

public <A extends Automaton<A,T>,T extends TransitionSymbol<T>> A toAutomaton(AutomataFactory<A,T> factory)

Description copied from class: RegularExpression

Transforms this regular expression into its equivalent automaton.

Specified by:

toAutomaton in class RegularExpression

Type Parameters:

A - the concrete type of Automaton that this method yields

T - the concrete type of TransitionSymbols that instances of A have on their transitions

Parameters:

factory - the factory that can be used to create the automaton

Returns:

the automaton

substringAux

public java.util.Set<RegularExpression.PartialSubstring> substringAux(int charsToSkip,
                                                                      int missingChars)

Description copied from class: RegularExpression

Returns the set of all possible substrings of this regular expression, starting at the given index (inclusive) and ending at the given index (exclusive). Each substring is decorated with the number of characters that are still missing to reach the beginning of the substring, and the number of characters that still need to be added to the string to reach the desired length.

Specified by:

substringAux in class RegularExpression

Parameters:

charsToSkip - the number of characters to skip before starting to collect the substring

missingChars - the number of missing characters to complete the substring

Returns:

the set of partial substrings

isEmpty

public boolean isEmpty()

Description copied from class: RegularExpression

Yields true if and only if this regular expression corresponds to the empty string or to no strings at all.

Specified by:

isEmpty in class RegularExpression

Returns:

true if that condition holds

is

public boolean is(java.lang.String str)

Description copied from class: RegularExpression

Yields true if and only if this regular expression corresponds to the given string.

Specified by:

is in class RegularExpression

Parameters:

str - the string

Returns:

true if that condition holds

maxLength

public int maxLength()

Description copied from interface: TransitionSymbol

Yields the maximum length of this symbol.

Returns:

the maximum length

minLength

public int minLength()

Description copied from interface: TransitionSymbol

Yields the minimum length of this symbol.

Returns:

the minimum length

mayContain

public boolean mayContain(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression may contain the given string.

Specified by:

mayContain in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

contains

public boolean contains(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression always contains the given string.

Specified by:

contains in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

mayStartWith

public boolean mayStartWith(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression may start with the given string.

Specified by:

mayStartWith in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

startsWith

public boolean startsWith(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression always starts with the given string.

Specified by:

startsWith in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

mayEndWith

public boolean mayEndWith(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression may end with the given string.

Specified by:

mayEndWith in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

endsWith

public boolean endsWith(java.lang.String s)

Description copied from class: RegularExpression

Yields true if and only if this regular expression always ends with the given string.

Specified by:

endsWith in class RegularExpression

Parameters:

s - the string

Returns:

true if that condition holds

unrollStarToFixedLength

protected RegularExpression unrollStarToFixedLength(int length)

Description copied from class: RegularExpression

Yields a new regular expression where all Star have been unrolled to a sequence of their inner regular expression of length length.

Specified by:

unrollStarToFixedLength in class RegularExpression

Parameters:

length - the length

Returns:

the regular expression with unrolled stars

reverse

public RegularExpression reverse()

Description copied from interface: TransitionSymbol

Yields a new symbol that corresponds to this one, but read back-to-front.

Returns:

the reversed symbol

topAsEmptyString

protected RegularExpression topAsEmptyString()

Description copied from class: RegularExpression

Yields a new regular expression where all TopAtom are assumed to have length zero.

Specified by:

topAsEmptyString in class RegularExpression

Returns:

the regular expression with empty top regular expressions

topAsSingleChar

protected RegularExpression topAsSingleChar()

Description copied from class: RegularExpression

Yields a new regular expression where all TopAtom are assumed to have length one.

Specified by:

topAsSingleChar in class RegularExpression

Returns:

the regular expression with shrinked top regular expressions

explode

public RegularExpression[] explode()

Description copied from class: RegularExpression

Yields a new regular expression that is the exploded version of this one, that is, where all atoms have been broken down to the composition of the characters that compose their inner strings.

Specified by:

explode in class RegularExpression

Returns:

the exploded regular expression

compareToAux

protected int compareToAux(RegularExpression other)

Description copied from class: RegularExpression

Auxiliary RegularExpression.compareTo(RegularExpression) that can safely assume that other is an object of the same class as this.

Specified by:

compareToAux in class RegularExpression

Parameters:

other - the other regular expression

Returns:

a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object

repeat

public RegularExpression repeat(long n)

Description copied from class: RegularExpression

Yields a new regular expression corresponding to the n-repetition of this.

Specified by:

repeat in class RegularExpression

Parameters:

n - number of repetitions

Returns:

a new regular expression corresponding to the n-repetition of this

trimLeft

public RegularExpression trimLeft()

Description copied from class: RegularExpression

Yields a new regular expression where leading whitespaces have been removed from this.

Specified by:

trimLeft in class RegularExpression

Returns:

a new regular expression where leading whitespaces have been removed from this

trimRight

public RegularExpression trimRight()

Description copied from class: RegularExpression

Yields a new regular expression where trailing whitespaces have been removed from this.

Specified by:

trimRight in class RegularExpression

Returns:

a new regular expression where trailing whitespaces have been removed from this

readsWhiteSpaceString

protected boolean readsWhiteSpaceString()

Description copied from class: RegularExpression

Checks whether this regular expression recognize a string made just of whitespaces.

Specified by:

readsWhiteSpaceString in class RegularExpression

Returns:

true if this regular expression recognize a string made just of whitespaces, false otherwise.