org.graalvm.shadowed.com.ibm.icu.impl.number.parse

Interface NumberParseMatcher

All Known Implementing Classes:

AffixMatcher, AffixPatternMatcher, CodePointMatcher, CombinedCurrencyMatcher, DecimalMatcher, IgnorablesMatcher, InfinityMatcher, MinusSignMatcher, MultiplierParseHandler, NanMatcher, PaddingMatcher, PercentMatcher, PermilleMatcher, PlusSignMatcher, RequireAffixValidator, RequireCurrencyValidator, RequireDecimalSeparatorValidator, RequireNumberValidator, ScientificMatcher, SeriesMatcher, SymbolMatcher, ValidationMatcher

public interface NumberParseMatcher

The core interface implemented by all matchers used for number parsing. Given a string, there should NOT be more than one way to consume the string with the same matcher applied multiple times. If there is, the non-greedy parsing algorithm will be unhappy and may enter an exponential-time loop. For example, consider the "A Matcher" that accepts "any number of As". Given the string "AAAA", there are 2^N = 8 ways to apply the A Matcher to this string: you could have the A Matcher apply 4 times to each character; you could have it apply just once to all the characters; you could have it apply to the first 2 characters and the second 2 characters; and so on. A better version of the "A Matcher" would be for it to accept exactly one A, and allow the algorithm to run it repeatedly to consume a string of multiple As. The A Matcher can implement the Flexible interface below to signal that it can be applied multiple times in a row.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	NumberParseMatcher.Flexible Matchers can implement the Flexible interface to indicate that they are optional and can be run repeatedly.

Method Summary

Modifier and Type	Method and Description
boolean	match(StringSegment segment, ParsedNumber result) Runs this matcher starting at the beginning of the given StringSegment.
void	postProcess(ParsedNumber result) Method called at the end of a parse, after all matchers have failed to consume any more chars.
boolean	smokeTest(StringSegment segment) Performs a fast "smoke check" for whether or not this matcher could possibly match against the given string segment.

Method Detail

match

boolean match(StringSegment segment,
              ParsedNumber result)

Runs this matcher starting at the beginning of the given StringSegment. If this matcher finds something interesting in the StringSegment, it should update the offset of the StringSegment corresponding to how many chars were matched.

Parameters:

segment - The StringSegment to match against. Matches always start at the beginning of the segment. The segment is guaranteed to contain at least one char.

result - The data structure to store results if the match succeeds.

Returns:

Whether this matcher thinks there may be more interesting chars beyond the end of the string segment.

smokeTest

boolean smokeTest(StringSegment segment)

Performs a fast "smoke check" for whether or not this matcher could possibly match against the given string segment. The test should be as fast as possible but also as restrictive as possible. For example, matchers can maintain a UnicodeSet of all code points that count possibly start a match. Matchers should use the StringSegment.startsWith(int) method in order to correctly handle case folding.

Parameters:

segment - The segment to check against.

Returns:

true if the matcher might be able to match against this segment; false if it definitely will not be able to match.

postProcess

void postProcess(ParsedNumber result)

Method called at the end of a parse, after all matchers have failed to consume any more chars. Allows a matcher to make final modifications to the result given the knowledge that no more matches are possible.

Parameters:

result - The data structure to store results.