org.apache.oro.text.awk

Class AwkCompiler

Implemented Interfaces:
PatternCompiler

public final class AwkCompiler
extends java.lang.Object
implements PatternCompiler

The AwkCompiler class is used to create compiled regular expressions conforming to the Awk regular expression syntax. It generates AwkPattern instances upon compilation to be used in conjunction with an AwkMatcher instance. AwkMatcher finds true leftmost-longest matches, so you must take care with how you formulate your regular expression to avoid matching more than you really want.

The supported regular expression syntax is a superset of traditional AWK, but NOT to be confused with GNU AWK or other AWK variants. Additionally, this AWK implementation is DFA-based and only supports 8-bit ASCII. Consequently, these classes can perform very fast pattern matches in most cases.

This is the traditional Awk syntax that is supported:

  • Special backslashed characters

    This is the extended syntax that is supported:

  • Version:
    2.0.8
    Since:
    1.0
    See Also:
    PatternCompiler, MalformedPatternException, AwkPattern, AwkMatcher

    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
    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.

    Method Summary

    Pattern
    compile(String pattern)
    Same as calling compile(pattern, AwkCompiler.DEFAULT_MASK);

    Pattern
    compile(String pattern, int options)
    Compiles an Awk regular expression into an AwkPattern instance that can be used by an AwkMatcher object to perform pattern matching.
    Pattern
    compile(char[] pattern)
    Same as calling compile(pattern, AwkCompiler.DEFAULT_MASK);

    Pattern
    compile(char[] pattern, int options)
    Compiles an Awk regular expression into an AwkPattern instance that can be used by an AwkMatcher object to perform pattern matching.

    Field Details

    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.
    Field Value:
    1

    DEFAULT_MASK

    public static final int DEFAULT_MASK
    The default mask for the compile methods. It is equal to 0 and indicates no special options are active.
    Field Value:
    0

    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 . metacharacters. When this mask is used, the . metacharacter will not match newlines. The default behavior is for . to match newlines.
    Field Value:
    2

    Method Details

    compile

    public Pattern compile(String pattern)
                throws MalformedPatternException
    Same as calling compile(pattern, AwkCompiler.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 an AwkPattern and can be reliably be casted to an AwkPattern.
    Throws:
    MalformedPatternException - If the compiled expression is not a valid Awk regular expression.

    compile

    public Pattern compile(String pattern,
                           int options)
                throws MalformedPatternException
    Compiles an Awk regular expression into an AwkPattern instance that can be used by an AwkMatcher object to perform pattern matching.

    Specified by:
    compile in interface PatternCompiler
    Parameters:
    pattern - An Awk regular expression to compile.
    options - A set of flags giving the compiler instructions on how to treat the regular expression. Currently the only meaningful flag is AwkCompiler.CASE_INSENSITIVE_MASK.
    Returns:
    A Pattern instance constituting the compiled regular expression. This instance will always be an AwkPattern and can be reliably be casted to an AwkPattern.
    Throws:
    MalformedPatternException - If the compiled expression is not a valid Awk regular expression.

    compile

    public Pattern compile(char[] pattern)
                throws MalformedPatternException
    Same as calling compile(pattern, AwkCompiler.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 an AwkPattern and can be reliably be casted to an AwkPattern.
    Throws:
    MalformedPatternException - If the compiled expression is not a valid Awk regular expression.

    compile

    public Pattern compile(char[] pattern,
                           int options)
                throws MalformedPatternException
    Compiles an Awk regular expression into an AwkPattern instance that can be used by an AwkMatcher object to perform pattern matching.

    Specified by:
    compile in interface PatternCompiler
    Parameters:
    pattern - An Awk regular expression to compile.
    options - A set of flags giving the compiler instructions on how to treat the regular expression. Currently the only meaningful flag is AwkCompiler.CASE_INSENSITIVE_MASK.
    Returns:
    A Pattern instance constituting the compiled regular expression. This instance will always be an AwkPattern and can be reliably be casted to an AwkPattern.
    Throws:
    MalformedPatternException - If the compiled expression is not a valid Awk regular expression.

    Copyright B) 2000-2003 Apache Software Foundation. All Rights Reserved.