Package org.apache.oro.text.regex

Class Perl5Matcher

  • All Implemented Interfaces:
    PatternMatcher
    public final class Perl5Matcher
extends java.lang.Object
implements PatternMatcher
    The Perl5Matcher class is used to match regular expressions (conforming to the Perl5 regular expression syntax) generated by Perl5Compiler.

    Perl5Compiler and Perl5Matcher are designed with the intent that you use a separate instance of each per thread to avoid the overhead of both synchronization and concurrent access (e.g., a match that takes a long time in one thread will block the progress of another thread with a shorter match). If you want to use a single instance of each in a concurrent program, you must appropriately protect access to the instances with critical sections. If you want to share Perl5Pattern instances between concurrently executing instances of Perl5Matcher, you must compile the patterns with Perl5Compiler.READ_ONLY_MASK.

    Since:
    1.0
    See Also:
    PatternMatcher, Perl5Compiler

    • Field Detail

      • __lastSuccess

        private boolean __lastSuccess

      • __caseInsensitive

        private boolean __caseInsensitive

      • __previousChar

        private char __previousChar

      • __input

        private char[] __input

      • __originalInput

        private char[] __originalInput

      • __numParentheses

        private int __numParentheses

      • __bol

        private int __bol

      • __eol

        private int __eol

      • __currentOffset

        private int __currentOffset

      • __endOffset

        private int __endOffset

      • __program

        private char[] __program

      • __expSize

        private int __expSize

      • __inputOffset

        private int __inputOffset

      • __lastParen

        private int __lastParen

      • __beginMatchOffsets

        private int[] __beginMatchOffsets

      • __endMatchOffsets

        private int[] __endMatchOffsets

      • __stack

        private final java.util.Stack<int[]> __stack

      • __DEFAULT_LAST_MATCH_END_OFFSET

        private static final int __DEFAULT_LAST_MATCH_END_OFFSET
        See Also:
        Constant Field Values

      • __lastMatchInputEndOffset

        private int __lastMatchInputEndOffset

    • Constructor Detail

      • Perl5Matcher

        public Perl5Matcher()

    • Method Detail

      • __compare

        private static boolean __compare​(char[] s1,
                                 int s1off,
                                 char[] s2,
                                 int s2off,
                                 int n)

      • __findFirst

        private static int __findFirst​(char[] input,
                               int curr,
                               int endOffset,
                               char[] mustString)

      • __pushState

        private void __pushState​(int parenFloor)

      • __popState

        private void __popState()

      • __initInterpreterGlobals

        private void __initInterpreterGlobals​(Perl5Pattern expression,
                                      char[] input,
                                      int beginOffset,
                                      int endOff,
                                      int currentOffset)

      • __setLastMatchResult

        private void __setLastMatchResult()

      • __interpret

        private boolean __interpret​(Perl5Pattern expression,
                            char[] input,
                            int beginOffset,
                            int endOff,
                            int currentOffset)

      • __matchUnicodeClass

        private boolean __matchUnicodeClass​(char code,
                                    char[] __program1,
                                    int off,
                                    char opcode)

      • __tryExpression

        private boolean __tryExpression​(int offset)

      • __repeat

        private int __repeat​(int offset,
                     int max)

      • __match

        private boolean __match​(int offset)

      • _toLower

        static char[] _toLower​(char[] in)

      • matchesPrefix

        public boolean matchesPrefix​(char[] in,
                             Pattern pattern,
                             int offset)
        Determines if a prefix of a string (represented as a char[]) matches a given pattern, starting from a given offset into the string. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch().

        This method is useful for certain common token identification tasks that are made more difficult without this functionality.

        Specified by:
        matchesPrefix in interface PatternMatcher
        Parameters:
        in - The char[] to test for a prefix match.
        pattern - The Pattern to be matched.
        offset - The offset at which to start searching for the prefix.
        Returns:
        True if input matches pattern, false otherwise.

      • matchesPrefix

        public boolean matchesPrefix​(char[] input,
                             Pattern pattern)
        Determines if a prefix of a string (represented as a char[]) matches a given pattern. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch().

        This method is useful for certain common token identification tasks that are made more difficult without this functionality.

        Specified by:
        matchesPrefix in interface PatternMatcher
        Parameters:
        input - The char[] to test for a prefix match.
        pattern - The Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.

      • matchesPrefix

        public boolean matchesPrefix​(java.lang.String input,
                             Pattern pattern)
        Determines if a prefix of a string matches a given pattern. If a prefix of the string matches the pattern, a MatchResult instance representing the match is made accesible via getMatch().

        This method is useful for certain common token identification tasks that are made more difficult without this functionality.

        Specified by:
        matchesPrefix in interface PatternMatcher
        Parameters:
        input - The String to test for a prefix match.
        pattern - The Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.

      • matchesPrefix

        public boolean matchesPrefix​(PatternMatcherInput input,
                             Pattern pattern)
        Determines if a prefix of a PatternMatcherInput instance matches a given pattern. If there is a match, a MatchResult instance representing the match is made accesible via getMatch(). Unlike the contains(PatternMatcherInput, Pattern) method, the current offset of the PatternMatcherInput argument is not updated. However, unlike the matches(PatternMatcherInput, Pattern) method, matchesPrefix() will start its search from the current offset rather than the begin offset of the PatternMatcherInput.

        This method is useful for certain common token identification tasks that are made more difficult without this functionality.

        Specified by:
        matchesPrefix in interface PatternMatcher
        Parameters:
        input - The PatternMatcherInput to test for a prefix match.
        pattern - The Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.

      • matches

        public boolean matches​(char[] in,
                       Pattern pattern)
        Determines if a string (represented as a char[]) exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch(). The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        Note: matches() is not the same as sticking a ^ in front of your expression and a $ at the end of your expression in Perl5 and using the =~ operator, even though in many cases it will be equivalent. matches() literally looks for an exact match according to the rules of Perl5 expression matching. Therefore, if you have a pattern foo|foot and are matching the input foot it will not produce an exact match. But foot|foo will produce an exact match for either foot or foo. Remember, Perl5 regular expressions do not match the longest possible match. From the perlre manpage:

        Alternatives are tried from left to right, so the first alternative found for which the entire expression matches, is the one that is chosen. This means that alternatives are not necessarily greedy. For example: when matching foo|foot against "barefoot", only the "foo" part will match, as that is the first alternative tried, and it successfully matches the target string.

        Specified by:
        matches in interface PatternMatcher
        Parameters:
        in - The char[] to test for an exact match.
        pattern - The Perl5Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • matches

        public boolean matches​(java.lang.String input,
                       Pattern pattern)
        Determines if a string exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch(). The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        Note: matches() is not the same as sticking a ^ in front of your expression and a $ at the end of your expression in Perl5 and using the =~ operator, even though in many cases it will be equivalent. matches() literally looks for an exact match according to the rules of Perl5 expression matching. Therefore, if you have a pattern foo|foot and are matching the input foot it will not produce an exact match. But foot|foo will produce an exact match for either foot or foo. Remember, Perl5 regular expressions do not match the longest possible match. From the perlre manpage:

        Alternatives are tried from left to right, so the first alternative found for which the entire expression matches, is the one that is chosen. This means that alternatives are not necessarily greedy. For example: when matching foo|foot against "barefoot", only the "foo" part will match, as that is the first alternative tried, and it successfully matches the target string.

        Specified by:
        matches in interface PatternMatcher
        Parameters:
        input - The String to test for an exact match.
        pattern - The Perl5Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • matches

        public boolean matches​(PatternMatcherInput input,
                       Pattern pattern)
        Determines if the contents of a PatternMatcherInput instance exactly matches a given pattern. If there is an exact match, a MatchResult instance representing the match is made accesible via getMatch() . Unlike the contains(PatternMatcherInput, Pattern) method, the current offset of the PatternMatcherInput argument is not updated. You should remember that the region between the begin (NOT the current) and end offsets of the PatternMatcherInput will be tested for an exact match.

        The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        Note: matches() is not the same as sticking a ^ in front of your expression and a $ at the end of your expression in Perl5 and using the =~ operator, even though in many cases it will be equivalent. matches() literally looks for an exact match according to the rules of Perl5 expression matching. Therefore, if you have a pattern foo|foot and are matching the input foot it will not produce an exact match. But foot|foo will produce an exact match for either foot or foo. Remember, Perl5 regular expressions do not match the longest possible match. From the perlre manpage:

        Alternatives are tried from left to right, so the first alternative found for which the entire expression matches, is the one that is chosen. This means that alternatives are not necessarily greedy. For example: when matching foo|foot against "barefoot", only the "foo" part will match, as that is the first alternative tried, and it successfully matches the target string.

        Specified by:
        matches in interface PatternMatcher
        Parameters:
        input - The PatternMatcherInput to test for a match.
        pattern - The Perl5Pattern to be matched.
        Returns:
        True if input matches pattern, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • contains

        public boolean contains​(java.lang.String input,
                        Pattern pattern)
        Determines if a string contains a pattern. If the pattern is matched by some substring of the input, a MatchResult instance representing the first such match is made acessible via getMatch(). If you want to access subsequent matches you should either use a PatternMatcherInput object or use the offset information in the MatchResult to create a substring representing the remaining input. Using the MatchResult offset information is the recommended method of obtaining the parts of the string preceeding the match and following the match.

        The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        Specified by:
        contains in interface PatternMatcher
        Parameters:
        input - The String to test for a match.
        pattern - The Perl5Pattern to be matched.
        Returns:
        True if the input contains a pattern match, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • contains

        public boolean contains​(char[] in,
                        Pattern pattern)
        Determines if a string (represented as a char[]) contains a pattern. If the pattern is matched by some substring of the input, a MatchResult instance representing the first such match is made acessible via getMatch(). If you want to access subsequent matches you should either use a PatternMatcherInput object or use the offset information in the MatchResult to create a substring representing the remaining input. Using the MatchResult offset information is the recommended method of obtaining the parts of the string preceeding the match and following the match.

        The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        Specified by:
        contains in interface PatternMatcher
        Parameters:
        in - The char[] to test for a match.
        pattern - The Perl5Pattern to be matched.
        Returns:
        True if the input contains a pattern match, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • contains

        public boolean contains​(PatternMatcherInput input,
                        Pattern pattern)
        Determines if the contents of a PatternMatcherInput, starting from the current offset of the input contains a pattern. If a pattern match is found, a MatchResult instance representing the first such match is made acessible via getMatch(). The current offset of the PatternMatcherInput is set to the offset corresponding to the end of the match, so that a subsequent call to this method will continue searching where the last call left off. You should remember that the region between the begin and end offsets of the PatternMatcherInput are considered the input to be searched, and that the current offset of the PatternMatcherInput reflects where a search will start from. Matches extending beyond the end offset of the PatternMatcherInput will not be matched. In other words, a match must occur entirely between the begin and end offsets of the input. See PatternMatcherInput for more details.

        As a side effect, if a match is found, the PatternMatcherInput match offset information is updated. See the PatternMatcherInput.setMatchOffsets(int, int) method for more details.

        The pattern must be a Perl5Pattern instance, otherwise a ClassCastException will be thrown. You are not required to, and indeed should NOT try to (for performance reasons), catch a ClassCastException because it will never be thrown as long as you use a Perl5Pattern as the pattern parameter.

        This method is usually used in a loop as follows: 

         PatternMatcher matcher;
 PatternCompiler compiler;
 Pattern pattern;
 PatternMatcherInput input;
 MatchResult result;

 compiler = new Perl5Compiler();
 matcher = new Perl5Matcher();

 try {
        pattern = compiler.compile(somePatternString);
 } catch (MalformedPatternException e) {
        System.err.println("Bad pattern.");
        System.err.println(e.getMessage());
        return;
 }

 input = new PatternMatcherInput(someStringInput);

 while (matcher.contains(input, pattern)) {
        result = matcher.getMatch();
        // Perform whatever processing on the result you want.
 }

        Specified by:
        contains in interface PatternMatcher
        Parameters:
        input - The PatternMatcherInput to test for a match.
        pattern - The Pattern to be matched.
        Returns:
        True if the input contains a pattern match, false otherwise.
        Throws:
        java.lang.ClassCastException - If a Pattern instance other than a Perl5Pattern is passed as the pattern parameter.

      • getMatch

        public MatchResult getMatch()
        Fetches the last match found by a call to a matches() or contains() method. If you plan on modifying the original search input, you must call this method BEFORE you modify the original search input, as a lazy evaluation technique is used to create the MatchResult. This reduces the cost of pattern matching when you don't care about the actual match and only care if the pattern occurs in the input. Otherwise, a MatchResult would be created for every match found, whether or not the MatchResult was later used by a call to getMatch().

        Specified by:
        getMatch in interface PatternMatcher
        Returns:
        A MatchResult instance containing the pattern match found by the last call to any one of the matches() or contains() methods. If no match was found by the last call, returns null.