Package com.sonar.sslr.impl.channel

Class BlackHoleChannel

java.lang.Object

org.sonar.sslr.channel.Channel<Lexer>

com.sonar.sslr.impl.channel.BlackHoleChannel

public class BlackHoleChannel
extends Channel<Lexer>

Allows to skip characters, which match given regular expression.

Mostly this channel is used with regular expression "\s++" to remove all whitespace characters. And in such case this channel should be the first one in a sequence of channels for performance reasons, because generally whitespace characters are encountered more often than all other and especially between others.

Constructor Summary

Constructors

Constructor	Description
BlackHoleChannel(String regexp)

Method Summary

Modifier and Type	Method	Description
boolean	consume(CodeReader code, Lexer lexer)	Tries to consume the character stream at the current reading cursor position (provided by the CodeReader).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BlackHoleChannel

public BlackHoleChannel(String regexp)

Throws:

PatternSyntaxException - if the expression's syntax is invalid

Method Detail

consume

public boolean consume(CodeReader code,
                       Lexer lexer)

Description copied from class: Channel

Tries to consume the character stream at the current reading cursor position (provided by the CodeReader). If the character stream is consumed the method must return true and the OUTPUT object can be fed.

Specified by:

consume in class Channel<Lexer>

Parameters:

code - the handle on the input character stream

lexer - the OUTPUT that can be optionally fed by the Channel

Returns:

false if the Channel doesn't want to consume the character stream, true otherwise.