gnu.regexp
public class RE extends REToken
A regular expression object (class RE) is compiled by constructing it
from a String, StringBuffer or character array, with optional
compilation flags (below)
and an optional syntax specification (see RESyntax; if not specified,
RESyntax.RE_SYNTAX_PERL5
is used).
Various methods attempt to match input text against a compiled regular expression. These methods are:
isMatch
: returns true if the input text in its entirety
matches the regular expression pattern.
getMatch
: returns the first match found in the input text,
or null if no match is found.
getAllMatches
: returns an array of all non-overlapping
matches found in the input text. If no matches are found, the array is
zero-length.
substitute
: substitute the first occurence of the pattern
in the input text with a replacement string (which may include
metacharacters $0-$9, see REMatch.substituteInto).
substituteAll
: same as above, but repeat for each match
before returning.
getMatchEnumeration
: returns an REMatchEnumeration object
that allows iteration over the matches (see REMatchEnumeration for some
reasons why you may want to do this instead of using getAllMatches
.
These methods all have similar argument lists. The input can be a String, a character array, a StringBuffer, a Reader or an InputStream of some sort. Note that when using a Reader or InputStream, the stream read position cannot be guaranteed after attempting a match (this is not a bug, but a consequence of the way regular expressions work). Using an REMatchEnumeration can eliminate most positioning problems.
The optional index argument specifies the offset from the beginning of the text at which the search should start (see the descriptions of some of the execution flags for how this can affect positional pattern operators). For a Reader or InputStream, this means an offset from the current read position, so subsequent calls with the same index argument on a Reader or an InputStream will not necessarily access the same position on the stream, whereas repeated searches at a given index in a fixed string will return consistent results.
You can optionally affect the execution environment by using a combination of execution flags (constants listed below).
All operations on a regular expression are performed in a thread-safe manner.
Version: 1.1.4-dev, to be released
Field Summary | |
---|---|
static int | REG_ANCHORINDEX
Execution flag.
|
static int | REG_DOT_NEWLINE
Compilation flag. |
static int | REG_ICASE
Compilation flag. |
static int | REG_MULTILINE
Compilation flag. |
static int | REG_NOTBOL
Execution flag.
|
static int | REG_NOTEOL
Execution flag.
|
static int | REG_NO_INTERPOLATE
Execution flag.
|
Constructor Summary | |
---|---|
RE(Object pattern)
Constructs a regular expression pattern buffer without any compilation
flags set, and using the default syntax (RESyntax.RE_SYNTAX_PERL5).
| |
RE(Object pattern, int cflags)
Constructs a regular expression pattern buffer using the specified
compilation flags and the default syntax (RESyntax.RE_SYNTAX_PERL5).
| |
RE(Object pattern, int cflags, RESyntax syntax)
Constructs a regular expression pattern buffer using the specified
compilation flags and regular expression syntax.
| |
protected | RE() |
Method Summary | |
---|---|
boolean | chain(REToken next) |
void | dump(StringBuffer os) |
REMatch[] | getAllMatches(Object input)
Returns an array of all matches found in the input.
|
REMatch[] | getAllMatches(Object input, int index)
Returns an array of all matches found in the input,
beginning at the specified index position.
|
REMatch[] | getAllMatches(Object input, int index, int eflags)
Returns an array of all matches found in the input string,
beginning at the specified index position and using the specified
execution flags.
|
static String | getLocalizedMessage(String key) |
REMatch | getMatch(Object input)
Returns the first match found in the input. |
REMatch | getMatch(Object input, int index)
Returns the first match found in the input, beginning
the search at the specified index. |
REMatch | getMatch(Object input, int index, int eflags)
Returns the first match found in the input, beginning
the search at the specified index, and using the specified
execution flags. |
REMatch | getMatch(Object input, int index, int eflags, StringBuffer buffer)
Returns the first match found in the input, beginning the search
at the specified index, and using the specified execution flags.
|
REMatchEnumeration | getMatchEnumeration(Object input)
Returns an REMatchEnumeration that can be used to iterate over the
matches found in the input text.
|
REMatchEnumeration | getMatchEnumeration(Object input, int index)
Returns an REMatchEnumeration that can be used to iterate over the
matches found in the input text.
|
REMatchEnumeration | getMatchEnumeration(Object input, int index, int eflags)
Returns an REMatchEnumeration that can be used to iterate over the
matches found in the input text.
|
REMatch | getMatchImpl(CharIndexed input, int anchor, int eflags, StringBuffer buffer) |
int | getMinimumLength()
Returns the minimum number of characters that could possibly
constitute a match of this regular expression. |
int | getNumSubs()
Returns the maximum number of subexpressions in this regular expression.
|
protected void | initialize(Object patternObj, int cflags, RESyntax syntax, int myIndex, int nextSub) |
boolean | isMatch(Object input)
Checks if the regular expression matches the input in its entirety.
|
boolean | isMatch(Object input, int index)
Checks if the input string, starting from index, is an exact match of
this regular expression.
|
boolean | isMatch(Object input, int index, int eflags)
Checks if the input, starting from index and using the specified
execution flags, is an exact match of this regular expression.
|
boolean | match(CharIndexed input, REMatch mymatch) |
void | setUncle(REToken uncle) |
String | substitute(Object input, String replace)
Substitutes the replacement text for the first match found in the input.
|
String | substitute(Object input, String replace, int index)
Substitutes the replacement text for the first match found in the input
beginning at the specified index position. |
String | substitute(Object input, String replace, int index, int eflags)
Substitutes the replacement text for the first match found in the input
string, beginning at the specified index position and using the
specified execution flags.
|
String | substituteAll(Object input, String replace)
Substitutes the replacement text for each non-overlapping match found
in the input text.
|
String | substituteAll(Object input, String replace, int index)
Substitutes the replacement text for each non-overlapping match found
in the input text, starting at the specified index.
|
String | substituteAll(Object input, String replace, int index, int eflags)
Substitutes the replacement text for each non-overlapping match found
in the input text, starting at the specified index and using the
specified execution flags.
|
String | toString()
Return a human readable form of the compiled regular expression,
useful for debugging. |
static String | version() Returns a string representing the version of the gnu.regexp package. |
This example demonstrates the results of various ways of matching on a substring.
// Results:
String s = "food bar fool";
RE exp = new RE("^foo.");
REMatch m0 = exp.getMatch(s);
REMatch m1 = exp.getMatch(s.substring(8));
REMatch m2 = exp.getMatch(s.substring(8),0,RE.REG_NOTBOL);
REMatch m3 = exp.getMatch(s,8);
REMatch m4 = exp.getMatch(s,8,RE.REG_ANCHORINDEX);
// m0 = "food"
// m1 = "fool"
// m2 = null
// m3 = null
// m4 = "fool"
Parameters: pattern A regular expression pattern, in the form of a String, StringBuffer or char[]. Other input types will be converted to strings using the toString() method.
Throws: REException The input pattern could not be parsed. NullPointerException The pattern was null.
Parameters: pattern A regular expression pattern, in the form of a String, StringBuffer, or char[]. Other input types will be converted to strings using the toString() method. cflags The logical OR of any combination of the compilation flags listed above.
Throws: REException The input pattern could not be parsed. NullPointerException The pattern was null.
Parameters: pattern A regular expression pattern, in the form of a String, StringBuffer, or char[]. Other input types will be converted to strings using the toString() method. cflags The logical OR of any combination of the compilation flags listed above. syntax The type of regular expression syntax to use.
Throws: REException The input pattern could not be parsed. NullPointerException The pattern was null.
Parameters: input The input text.
Returns: a non-null (but possibly zero-length) array of matches
Parameters: input The input text. index The offset index at which the search should be begin.
Returns: a non-null (but possibly zero-length) array of matches
Parameters: input The input text. index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Returns: a non-null (but possibly zero-length) array of matches
Parameters: input The input text.
Returns: An REMatch instance referencing the match, or null if none.
Parameters: input The input text. index The offset within the text to begin looking for a match.
Returns: An REMatch instance referencing the match, or null if none.
Parameters: input The input text. index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Returns: An REMatch instance referencing the match, or null if none.
Parameters: input The input text. index The offset index at which the search should be begin. eflags The logical OR of any execution flags above. buffer The StringBuffer to save pre-match text in.
Returns: An REMatch instance referencing the match, or null if none.
Parameters: input The input text.
Returns: A non-null REMatchEnumeration instance.
Parameters: input The input text. index The offset index at which the search should be begin.
Returns: A non-null REMatchEnumeration instance, with its input cursor set to the index position specified.
Parameters: input The input text. index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Returns: A non-null REMatchEnumeration instance, with its input cursor set to the index position specified.
Parameters: input The input text.
Parameters: input The input text. index The offset index at which the search should be begin.
Parameters: input The input text. index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
Returns: A String interpolating the substituted text.
See Also: REMatch
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto). index The offset index at which the search should be begin.
Returns: A String containing the substring of the input, starting at the index position, and interpolating the substituted text.
See Also: REMatch
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto). index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Returns: A String containing the substring of the input, starting at the index position, and interpolating the substituted text.
See Also: REMatch
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
Returns: A String interpolating the substituted text.
See Also: REMatch
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto). index The offset index at which the search should be begin.
Returns: A String containing the substring of the input, starting at the index position, and interpolating the substituted text.
See Also: REMatch
Parameters: input The input text. replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto). index The offset index at which the search should be begin. eflags The logical OR of any execution flags above.
Returns: A String containing the substring of the input, starting at the index position, and interpolating the substituted text.
See Also: REMatch