org.apache.oro.text
Class GlobCompiler
java.lang.Object
org.apache.oro.text.GlobCompiler
- PatternCompiler
public final class GlobCompiler
extends java.lang.Object
The GlobCompiler class will compile a glob expression into a Perl5Pattern
that may be used to match patterns in conjunction with Perl5Matcher.
Rather than create extra GlobMatcher and GlobPattern classes tailored
to the task of matching glob expressions, we have simply reused the
Perl5 regular expression classes from org.apache.oro.text.regex by
making GlobCompiler translate a glob expression into a Perl5 expression
that is compiled by a Perl5Compiler instance internal to the GlobCompiler.
Because there are various similar glob expression syntaxes, GlobCompiler
tries to provide a small amount of customization by providing the
STAR_CANNOT_MATCH_NULL_MASK
and
QUESTION_MATCHES_ZERO_OR_ONE_MASK
compilation options.
The GlobCompiler expression syntax is based on Unix shell glob expressions
but should be usable to simulate Win32 wildcards. The following syntax
is supported:
- * - Matches zero or more instances of any character. If the
STAR_CANNOT_MATCH_NULL_MASK option is used, * matches
one or more instances of any character.
- ? - Matches one instance of any character. If the
QUESTION_MATCHES_ZERO_OR_ONE_MASK option is used, ?
matches zero or one instances of any character.
- [...] - Matches any of characters enclosed by the brackets.
* and ? lose their special meanings within a
character class. Additionaly if the first character following
the opening bracket is a ! or a ^, then any
character not in the character class is matched. A -
between two characters can be used to denote a range. A
- at the beginning or end of the character class matches
itself rather than referring to a range. A ] immediately
following the opening [ matches itself rather than
indicating the end of the character class, otherwise it must be
escaped with a backslash to refer to itself.
- \ - A backslash matches itself in most situations. But
when a special character such as a * follows it, a
backslash escapes the character, indicating that
the special chracter should be interpreted as a normal character
instead of its special meaning.
- All other characters match themselves.
Please remember that the when you construct a Java string in Java code,
the backslash character is itself a special Java character, and it must
be double backslashed to represent single backslash in a regular
expression.
Version:
- 1.0
PatternCompiler
, Perl5Matcher
static int | CASE_INSENSITIVE_MASK - A mask passed as an option to the
compile methods
to indicate a compiled glob expression should be case insensitive.
|
static int | DEFAULT_MASK - The default mask for the
compile methods.
|
static int | QUESTION_MATCHES_ZERO_OR_ONE_MASK - A mask passed as an option to the
compile methods
to indicate that a ? should not be allowed to match the null string.
|
static int | READ_ONLY_MASK - A mask passed as an option to the
compile methods
to indicate that the resulting Perl5Pattern should be treated as a
read only data structure by Perl5Matcher, making it safe to share
a single Perl5Pattern instance among multiple threads without needing
synchronization.
|
static int | STAR_CANNOT_MATCH_NULL_MASK - A mask passed as an option to the
compile methods
to indicate that a * should not be allowed to match the null string.
|
Pattern | compile(String pattern) - Same as calling compile(pattern, GlobCompiler.DEFAULT_MASK);
|
Pattern | compile(String pattern, int options) - Compiles a Glob expression into a Perl5Pattern instance that
can be used by a Perl5Matcher object to perform pattern matching.
|
Pattern | compile(char[] pattern) - Same as calling compile(pattern, GlobCompiler.DEFAULT_MASK);
|
Pattern | compile(char[] pattern, int options) - Compiles a Glob expression into a Perl5Pattern instance that
can be used by a Perl5Matcher object to perform pattern matching.
|
static String | globToPerl5(char[] pattern, int options) - This static method is the basic engine of the Glob PatternCompiler
implementation.
|
CASE_INSENSITIVE_MASK
public static final int CASE_INSENSITIVE_MASK
A mask passed as an option to the compile
methods
to indicate a compiled glob expression should be case insensitive.
- 1
DEFAULT_MASK
public static final int DEFAULT_MASK
The default mask for the compile
methods.
It is equal to 0. The default behavior is for a glob expression to
be case sensitive unless it is compiled with the CASE_INSENSITIVE_MASK
option.
- 0
QUESTION_MATCHES_ZERO_OR_ONE_MASK
public static final int QUESTION_MATCHES_ZERO_OR_ONE_MASK
A mask passed as an option to the compile
methods
to indicate that a ? should not be allowed to match the null string.
The normal behavior of the ? metacharacter is that it may match any 1
character. This mask causes it to match 0 or 1 characters.
- 4
READ_ONLY_MASK
public static final int READ_ONLY_MASK
A mask passed as an option to the compile
methods
to indicate that the resulting Perl5Pattern should be treated as a
read only data structure by Perl5Matcher, making it safe to share
a single Perl5Pattern instance among multiple threads without needing
synchronization. Without this option, Perl5Matcher reserves the right
to store heuristic or other information in Perl5Pattern that might
accelerate future matches. When you use this option, Perl5Matcher will
not store or modify any information in a Perl5Pattern. Use this option
when you want to share a Perl5Pattern instance among multiple threads
using different Perl5Matcher instances.
- 8
STAR_CANNOT_MATCH_NULL_MASK
public static final int STAR_CANNOT_MATCH_NULL_MASK
A mask passed as an option to the compile
methods
to indicate that a * should not be allowed to match the null string.
The normal behavior of the * metacharacter is that it may match any
0 or more characters. This mask causes it to match 1 or more
characters of anything.
- 2
GlobCompiler
public GlobCompiler()
The default GlobCompiler constructor. It initializes an internal
Perl5Compiler instance to compile translated glob expressions.
compile
public Pattern compile(String pattern)
throws MalformedPatternException
Same as calling
compile(pattern, GlobCompiler.DEFAULT_MASK);
- compile in interface PatternCompiler
pattern
- A regular expression to compile.
- A Pattern instance constituting the compiled regular expression.
This instance will always be a Perl5Pattern and can be reliably
casted to a Perl5Pattern.
MalformedPatternException
- If the compiled expression
is not a valid Glob expression.
compile
public Pattern compile(String pattern,
int options)
throws MalformedPatternException
Compiles a Glob expression into a Perl5Pattern instance that
can be used by a Perl5Matcher object to perform pattern matching.
- compile in interface PatternCompiler
pattern
- A Glob expression to compile.options
- A set of flags giving the compiler instructions on
how to treat the glob expression. The flags
are a logical OR of any number of the 3 MASK
constants. For example:
regex =
compiler.compile("*.*", GlobCompiler.
CASE_INSENSITIVE_MASK |
GlobCompiler.STAR_CANNOT_MATCH_NULL_MASK);
This says to compile the pattern so that *
cannot match the null string and to perform
matches in a case insensitive manner.
- A Pattern instance constituting the compiled expression.
This instance will always be a Perl5Pattern and can be reliably
casted to a Perl5Pattern.
MalformedPatternException
- If the compiled expression
is not a valid Glob expression.
compile
public Pattern compile(char[] pattern)
throws MalformedPatternException
Same as calling
compile(pattern, GlobCompiler.DEFAULT_MASK);
- compile in interface PatternCompiler
pattern
- A regular expression to compile.
- A Pattern instance constituting the compiled regular expression.
This instance will always be a Perl5Pattern and can be reliably
casted to a Perl5Pattern.
MalformedPatternException
- If the compiled expression
is not a valid Glob expression.
compile
public Pattern compile(char[] pattern,
int options)
throws MalformedPatternException
Compiles a Glob expression into a Perl5Pattern instance that
can be used by a Perl5Matcher object to perform pattern matching.
- compile in interface PatternCompiler
pattern
- A Glob expression to compile.options
- A set of flags giving the compiler instructions on
how to treat the glob expression. The flags
are a logical OR of any number of the 3 MASK
constants. For example:
regex =
compiler.compile(pattern, GlobCompiler.
CASE_INSENSITIVE_MASK |
GlobCompiler.STAR_CANNOT_MATCH_NULL_MASK);
This says to compile the pattern so that *
cannot match the null string and to perform
matches in a case insensitive manner.
- A Pattern instance constituting the compiled expression.
This instance will always be a Perl5Pattern and can be reliably
casted to a Perl5Pattern.
MalformedPatternException
- If the compiled expression
is not a valid Glob expression.
globToPerl5
public static String globToPerl5(char[] pattern,
int options)
This static method is the basic engine of the Glob PatternCompiler
implementation. It takes a glob expression in the form of a character
array and converts it into a String representation of a Perl5 pattern.
The method is made public so that programmers may use it for their
own purposes. However, the GlobCompiler compile methods work by
converting the glob pattern to a Perl5 pattern using this method, and
then invoking the compile() method of an internally stored Perl5Compiler
instance.
pattern
- A character array representation of a Glob pattern.
- A String representation of a Perl5 pattern equivalent to the
Glob pattern.
Copyright B) 2000-2003 Apache Software Foundation. All Rights Reserved.