org.apache.oro.text.regex
Class Perl5Compiler

java.lang.Object
  extended byorg.apache.oro.text.regex.Perl5Compiler
All Implemented Interfaces:
PatternCompiler

public final class Perl5Compiler
extends Object
implements PatternCompiler

The Perl5Compiler class is used to create compiled regular expressions conforming to the Perl5 regular expression syntax. It generates Perl5Pattern instances upon compilation to be used in conjunction with a Perl5Matcher instance. Please see the user's guide for more information about Perl5 regular expressions.

Version:
$Id: Perl5Compiler.java,v 1.1 2005/10/05 20:19:56 eytanadar Exp $
Author:
Daniel F. Savarese
See Also:
PatternCompiler, MalformedPatternException, Perl5Pattern, Perl5Matcher

Field Summary
static int CASE_INSENSITIVE_MASK
          A mask passed as an option to the compile methods to indicate a compiled regular expression should be case insensitive.
static int DEFAULT_MASK
          The default mask for the compile methods.
static int EXTENDED_MASK
          A mask passed as an option to the compile methods to indicate a compiled regular expression should be treated as a Perl5 extended pattern (i.e., a pattern using the /x modifier).
static int MULTILINE_MASK
          A mask passed as an option to the compile methods to indicate a compiled regular expression should treat input as having multiple lines.
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 SINGLELINE_MASK
          A mask passed as an option to the compile methods to indicate a compiled regular expression should treat input as being a single line.
 
Constructor Summary
Perl5Compiler()
           
 
Method Summary
 Pattern compile(char[] pattern)
          Same as calling compile(pattern, Perl5Compiler.DEFAULT_MASK);
 Pattern compile(char[] pattern, int options)
          Compiles a Perl5 regular expression into a Perl5Pattern instance that can be used by a Perl5Matcher object to perform pattern matching.
 Pattern compile(String pattern)
          Same as calling compile(pattern, Perl5Compiler.DEFAULT_MASK);
 Pattern compile(String pattern, int options)
          Compiles a Perl5 regular expression into a Perl5Pattern instance that can be used by a Perl5Matcher object to perform pattern matching.
static String quotemeta(char[] expression)
          Given a character string, returns a Perl5 expression that interprets each character of the original string literally.
static String quotemeta(String expression)
          Given a character string, returns a Perl5 expression that interprets each character of the original string literally.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

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 regular expression to be case sensitive and to not specify if it is multiline or singleline. When MULITLINE_MASK and SINGLINE_MASK are not defined, the ^, $, and . metacharacters are interpreted according to the value of isMultiline() in Perl5Matcher. The default behavior of Perl5Matcher is to treat the Perl5Pattern as though MULTILINE_MASK were enabled. If isMultiline() returns false, then the pattern is treated as though SINGLINE_MASK were set. However, compiling a pattern with the MULTILINE_MASK or SINGLELINE_MASK masks will ALWAYS override whatever behavior is specified by the setMultiline() in Perl5Matcher.

See Also:
Constant Field Values

CASE_INSENSITIVE_MASK

public static final int CASE_INSENSITIVE_MASK
A mask passed as an option to the compile methods to indicate a compiled regular expression should be case insensitive.

See Also:
Constant Field Values

MULTILINE_MASK

public static final int MULTILINE_MASK
A mask passed as an option to the compile methods to indicate a compiled regular expression should treat input as having multiple lines. This option affects the interpretation of the ^ and $ metacharacters. When this mask is used, the ^ metacharacter matches at the beginning of every line, and the $ metacharacter matches at the end of every line. Additionally the . metacharacter will not match newlines when an expression is compiled with MULTILINE_MASK , which is its default behavior. The SINGLELINE_MASK and MULTILINE_MASK should not be used together.

See Also:
Constant Field Values

SINGLELINE_MASK

public static final int SINGLELINE_MASK
A mask passed as an option to the compile methods to indicate a compiled regular expression should treat input as being a single line. This option affects the interpretation of the ^ and $ metacharacters. When this mask is used, the ^ metacharacter matches at the beginning of the input, and the $ metacharacter matches at the end of the input. The ^ and $ metacharacters will not match at the beginning and end of lines occurring between the begnning and end of the input. Additionally, the . metacharacter will match newlines when an expression is compiled with SINGLELINE_MASK , unlike its default behavior. The SINGLELINE_MASK and MULTILINE_MASK should not be used together.

See Also:
Constant Field Values

EXTENDED_MASK

public static final int EXTENDED_MASK
A mask passed as an option to the compile methods to indicate a compiled regular expression should be treated as a Perl5 extended pattern (i.e., a pattern using the /x modifier). This option tells the compiler to ignore whitespace that is not backslashed or within a character class. It also tells the compiler to treat the # character as a metacharacter introducing a comment as in Perl. In other words, the # character will comment out any text in the regular expression between it and the next newline. The intent of this option is to allow you to divide your patterns into more readable parts. It is provided to maintain compatibility with Perl5 regular expressions, although it will not often make sense to use it in Java.

See Also:
Constant Field Values

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.

See Also:
Constant Field Values
Constructor Detail

Perl5Compiler

public Perl5Compiler()
Method Detail

quotemeta

public static final String quotemeta(char[] expression)
Given a character string, returns a Perl5 expression that interprets each character of the original string literally. In other words, all special metacharacters are quoted/escaped. This method is useful for converting user input meant for literal interpretation into a safe regular expression representing the literal input.

In effect, this method is the analog of the Perl5 quotemeta() builtin method.

Parameters:
expression - The expression to convert.
Returns:
A String containing a Perl5 regular expression corresponding to a literal interpretation of the pattern.

quotemeta

public static final String quotemeta(String expression)
Given a character string, returns a Perl5 expression that interprets each character of the original string literally. In other words, all special metacharacters are quoted/escaped. This method is useful for converting user input meant for literal interpretation into a safe regular expression representing the literal input.

In effect, this method is the analog of the Perl5 quotemeta() builtin method.

Returns:
A String containing a Perl5 regular expression corresponding to a literal interpretation of the pattern.

compile

public Pattern compile(char[] pattern,
                       int options)
                throws MalformedPatternException
Compiles a Perl5 regular expression into a Perl5Pattern instance that can be used by a Perl5Matcher object to perform pattern matching. Please see the user's guide for more information about Perl5 regular expressions.

Specified by:
compile in interface PatternCompiler
Parameters:
pattern - A Perl5 regular expression to compile.
options - A set of flags giving the compiler instructions on how to treat the regular expression. The flags are a logical OR of any number of the five MASK constants. For example:
 regex =
   compiler.compile(pattern, Perl5Compiler.
                    CASE_INSENSITIVE_MASK |
                    Perl5Compiler.MULTILINE_MASK);
                 
This says to compile the pattern so that it treats input as consisting of multiple lines and to perform matches in a case insensitive manner.
Returns:
A Pattern instance constituting the compiled regular expression. This instance will always be a Perl5Pattern and can be reliably casted to a Perl5Pattern.
Throws:
MalformedPatternException - If the compiled expression is not a valid Perl5 regular expression.

compile

public Pattern compile(char[] pattern)
                throws MalformedPatternException
Same as calling compile(pattern, Perl5Compiler.DEFAULT_MASK);

Specified by:
compile in interface PatternCompiler
Parameters:
pattern - A regular expression to compile.
Returns:
A Pattern instance constituting the compiled regular expression. This instance will always be a Perl5Pattern and can be reliably casted to a Perl5Pattern.
Throws:
MalformedPatternException - If the compiled expression is not a valid Perl5 regular expression.

compile

public Pattern compile(String pattern)
                throws MalformedPatternException
Same as calling compile(pattern, Perl5Compiler.DEFAULT_MASK);

Specified by:
compile in interface PatternCompiler
Parameters:
pattern - A regular expression to compile.
Returns:
A Pattern instance constituting the compiled regular expression. This instance will always be a Perl5Pattern and can be reliably casted to a Perl5Pattern.
Throws:
MalformedPatternException - If the compiled expression is not a valid Perl5 regular expression.

compile

public Pattern compile(String pattern,
                       int options)
                throws MalformedPatternException
Compiles a Perl5 regular expression into a Perl5Pattern instance that can be used by a Perl5Matcher object to perform pattern matching. Please see the user's guide for more information about Perl5 regular expressions.

Specified by:
compile in interface PatternCompiler
Parameters:
pattern - A Perl5 regular expression to compile.
options - A set of flags giving the compiler instructions on how to treat the regular expression. The flags are a logical OR of any number of the five MASK constants. For example:
 regex =
   compiler.compile("^\\w+\\d+$",
                    Perl5Compiler.CASE_INSENSITIVE_MASK |
                    Perl5Compiler.MULTILINE_MASK);
                 
This says to compile the pattern so that it treats input as consisting of multiple lines and to perform matches in a case insensitive manner.
Returns:
A Pattern instance constituting the compiled regular expression. This instance will always be a Perl5Pattern and can be reliably casted to a Perl5Pattern.
Throws:
MalformedPatternException - If the compiled expression is not a valid Perl5 regular expression.