Parser.java :  » Web-Framework » anvil » anvil » script » statements » taglib » Java Open Source

/*
 * $Id: Parser.java,v 1.4 2002/09/16 08:05:06 jkl Exp $
 *
 * Copyright (c) 2002 Njet Communications Ltd. All Rights Reserved.
 *
 * Use is subject to license terms, as defined in
 * Anvil Sofware License, Version 1.1. See LICENSE 
 * file, or http://njet.org/license-1.1.txt
 */
package anvil.script.statements.taglib;

import anvil.ErrorListener;
import anvil.Location;
import anvil.parser.DocumentHandler;
import anvil.parser.InputSource;
import anvil.parser.Locator;
import anvil.parser.URLInputSource;
import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;


public class Parser implements DocumentHandler
{

  private static final int STATE_NULL = 0;
  private static final int STATE_LIB = 1;
  private static final int STATE_LIB_ATTR = 2;
  private static final int STATE_TAG = 3;
  private static final int STATE_TAG_ATTR = 4;
  private static final int STATE_ATTR = 5;
  private static final int STATE_ATTR_ATTR = 6;

  private Locator _locator;
  private ErrorListener _listener;
  private TagLibrary _lib = null;
  private Tag _tag = null;
  private Attribute _attr = null;
  private String _property = null;
  private int _state = STATE_NULL;

  public Parser(ErrorListener listener)
  {
    _listener = listener;
  }

  
  public void error(String message)
  {
    _listener.error(_locator.getLocation(), message);
  }


  private String getName(anvil.parser.Tag tag)
  {
    String name = tag.getValue("name");
    if (name == null) {
      error("Attribute 'name' missing from tag");
      name = "";
    } else {
      if (!anvil.script.Grammar.isValidIdentifier(name)) {
       error("Value of attribute 'name' is not a valid identifier");
      }
    }
    return name;
  }


  public void setDocumentLocator(Locator locator)
  {
    _locator = locator;
  }
  


  public void startDocument()
  {
  }


  public void endDocument()
  {
  }
  

  public void handleCharacters(String cdata)
  {
    boolean ok = true;
    switch(_state) {
    case STATE_LIB_ATTR:
      ok = _lib.setAttribute(this, _property, cdata);
      break;
    case STATE_TAG_ATTR:
      ok = _tag.setAttribute(this, _property, cdata);
      break;
    case STATE_ATTR_ATTR:
      ok = _attr.setAttribute(this, _property, cdata);
      break;
    }
    if (!ok) {
      error("Invalid property '"+_property+"'");
    }
  }

  public void handleComment(String cdata)
  {
  }

  public void handleTag(anvil.parser.Tag tag)
  {
    String tagname = tag.getName();
    switch(_state) {
    case STATE_NULL:
      if (tagname.equalsIgnoreCase("taglib")) {
        _state = STATE_LIB;
        _lib = new TagLibrary(getName(tag));
        return;
      }
      break;

    case STATE_LIB:
      if (tagname.equalsIgnoreCase("tag")) {
        _state = STATE_TAG;
        _tag = new Tag(_lib, getName(tag));
        _lib.addTag(_tag);
        return;

      } else if (tagname.equalsIgnoreCase("/taglib")) {
        _state = STATE_NULL;
        return;

      }
      _state = STATE_LIB_ATTR;
      _property = tagname;
      return;

    case STATE_LIB_ATTR:
      if (tagname.equalsIgnoreCase("/"+_property)) {
        _state = STATE_LIB;
        return;
      } 
      break;

    case STATE_TAG:
      if (tagname.equalsIgnoreCase("attribute")) {
        _state = STATE_ATTR;
        _attr = new Attribute(getName(tag));
        _tag.addAttribute(_attr);
        return;

      } else if (tagname.equalsIgnoreCase("/tag")) {
        _state = STATE_LIB;
        return;

      }
      _state = STATE_TAG_ATTR;
      _property = tagname;
      return;

    case STATE_TAG_ATTR:
      if (tagname.equalsIgnoreCase("/"+_property)) {
        _state = STATE_TAG;
        return;
      } 
      break;

    case STATE_ATTR:
      if (tagname.equalsIgnoreCase("/attribute")) {
        _state = STATE_TAG;
        return;
      }
      _state = STATE_ATTR_ATTR;
      _property = tagname;
      return;

    case STATE_ATTR_ATTR:
      if (tagname.equalsIgnoreCase("/"+_property)) {
        _state = STATE_ATTR;
        return;
      } 
    }
    error("Invalid tag " + tag);
  }


  public void handleProcessingInstruction(String data)
  {
  }


  public TagLibrary getLibrary()
  {
    return _lib;
  }


  public static TagLibrary parse(ErrorListener listener, URL url, Location location, 
    String namespace, String tagns)
  {
    try {
      anvil.parser.Parser parser = new anvil.parser.Parser();
      Parser libparser = new Parser(listener);
      parser.parse(libparser, new URLInputSource(url));
      TagLibrary library = libparser.getLibrary();
      library.setNamespaces(namespace, tagns);
      return library;
    } catch (IOException e) {
    
      listener.error(location, "IO-Error while loading taglib description: "+e);
    }
    return null;
  }

  
}