source: trunk/src/ws/fugue88/jpath/SimplePathParser.java

/*
 * Created on Aug 31, 2005
 * 
 * $Log$
 * Revision 1.1  2005/09/21 22:00:45  dsowen
 * Split out the access stuff into accesslib.
 * New Creator interface off-loads object creation to user.
 *
 */
package ws.fugue88.jpath;

import java.nio.CharBuffer;
import java.text.ParseException;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author dsowen
 */
public class SimplePathParser extends PathParser {

        public Path parse(final String path) throws ParseException
        {
                final List parts = new LinkedList();

                CharSequence buff = CharBuffer.wrap(path);
                do {
                        final PathPart pp;
                        Matcher m;
                        if((m = IDENT.matcher(buff)).find()) {
                                pp = new Identifier(m.group(1));
                        } else if((m = NUM_SEL.matcher(buff)).find()) {
                                pp = new NumberSelector(m.group(1));
                        } else if((m = STR_SEL.matcher(buff)).find()) {
                                pp = new StringSelector(unquote(m.group(1)));
                        } else {
                                throw new ParseException(
                                                "Expected identifier or selector, found '"
                                                                + (buff.length() > 40 ? buff.subSequence(0, 37)
                                                                                + "..." : buff) + "'.", -1);
                        }
                        parts.add(pp);
                        buff = buff.subSequence(m.end(), buff.length());
                } while(buff.length() > 0);

                return new Path(parts);
        }

        private static final String IDENT_START = "A-Za-z_";
        private static final String IDENT_END = IDENT_START + "0-9";
        private static final Pattern IDENT = Pattern.compile("^/([" + IDENT_START
                        + "][" + IDENT_END + "]*)");

        private static final String NUM_LIT = "-?[0-9]+";
        private static final Pattern NUM_SEL = Pattern.compile("^\\[(" + NUM_LIT
                        + ")\\]");

        private static final String STR_LIT = "'((?:[^']|\\\\')*)'";
        private static final Pattern STR_SEL = Pattern.compile("^\\[" + STR_LIT
                        + "\\]");
}