javadoccomment.java

JAVA在编译原理上的应用。

package lolo.scans;

/** A recognizer class to scan for javadoc comments. 
 * <p>By default these symbols will be ignored.
 *
 * @author <a href="http://www.inf.uos.de/bernd" target="_blank">Bernd K&uuml;hl</a>
           (<a href="mailto:[e-mail]">[e-mail]</a>)
 */
public class JavadocComment extends SlashSlashComment {
    /** The legal characters. */ // A means ANY
    protected static final String chars = "A*/";
    /** The state table. */
    protected static final int newState [][] = {
        // current state, input => newstate
        // ANY  *   /  
        {  7,   7,  1   },  // state 0, find /
        {  7,   2,  7   },  // state 1, find * for /*
        {  7,   3,  7   },  // state 2, find * for /**
        {  4,   4,  7   },  // state 3, find * or any, /**/...*/ is no legal javadoc comment
        {  4,   5,  4   },  // state 4, find * or any
        {  4,   5,  6   }   // state 5, find / for */
                            // state 6, comment found
                            // state 7, error
    };

    public State nextChar(char ch) {
        // is ch a legal input character?
        int input = chars.indexOf(ch);
        if (input < 0) input = 0;
        
        boolean found = false, more = false;
        state = newState[state][input];
        switch(state) {
            case 7:	 break;    // error state, parse ends
            case 0:	 new RuntimeException("illegal state "+state); // cann't be..
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:	 more = true; break;
            case 6:	 found = true; break;
            default: new RuntimeException("illegal state "+state); // cann't be..
        }
        
        return stateObject.set(more, found);
    }
}