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{
import java.util.Vector;
}
/** Parse an entire html file, firing events to a single listener
* for each image and href link encountered. All tokens are
* defined to skip so the lexer will continue scarfing until EOF.
*/
class LinkExtractor extends Lexer;
options {
caseSensitive=false;
k=2;
filter=SCARF;
charVocabulary='\3'..'\177';
}
{
protected LinkListener listener;
public void addLinkListener(LinkListener listener) {
this.listener = listener;
}
public void removeLinkListener(LinkListener listener) {
this.listener = null;
}
public void fireImageLinkEvent(String target, int line) {
listener.imageReference(target, line);
}
public void fireHREFLinkEvent(String target, int line) {
listener.hrefReference(target, line);
}
/** strip quotes from "..." or '...' strings */
public static String stripQuotes(String src) {
int h = src.indexOf('"');
if ( h==-1 ) h = src.indexOf('\'');
int t = src.lastIndexOf('"');
if ( t==-1 ) t = src.lastIndexOf('\'');
if ( h==-1 || t==-1 ) return src;
return src.substring(h+1,t);
}
}
AHREF
: "<a" WS (ATTR)+ '>' {$setType(Token.SKIP);}
;
IMG : "<img" WS (ATTR)+ '>' {$setType(Token.SKIP);}
;
protected
ATTR
options {
ignore=WS;
}
: w:WORD '='
( s:STRING
| v:WORD
)
{
String target = s!=null ? stripQuotes(s.getText()) : v.getText();
if ( w.getText().equalsIgnoreCase("href") ) {
fireHREFLinkEvent(target, getLine());
}
else if ( w.getText().equalsIgnoreCase("src") ) {
fireImageLinkEvent(target, getLine());
}
}
;
/** Match until next whitespace; can be file, int, etc... */
protected
WORD: (
options {
generateAmbigWarnings=false;
}
: 'a'..'z' | '0'..'9' | '/' | '.' | '#' | '_'
)+
;
protected
STRING
: '"' (~'"')* '"'
| '\'' (~'\'')* '\''
;
protected
WS : ( ' '
| '\t'
| '\f'
| ( "\r\n" // DOS
| '\r' // Macintosh
| '\n' // Unix (the right way)
)
{ newline(); }
)
{ $setType(Token.SKIP); }
;
protected
SCARF
: WS // track line numbers while you scarf
| .
;
|
