wbxmlparser.java

本文档讲解了OTA的概念

// (c) 2001 Stefan Haustein
// Contributors: Bjorn Aadland

package org.kxml.wap;

import java.io.IOException;
import java.io.InputStream;
import java.util.*;
import org.kxml.Attribute;
import org.kxml.Xml;
import org.kxml.io.ParseException;
import org.kxml.parser.AbstractXmlParser;
import org.kxml.parser.ParseEvent;
import org.kxml.parser.StartTag;
import org.kxml.parser.Tag;

/** Still Todo:
 * <ul>
 * <li>implement Processing Instructions</li>
 * <li>implement support for more than one codepages</li>
 * </ul>
 */

public class WbxmlParser extends AbstractXmlParser {
    
    InputStream in;
    
    // all known code pages and their tables
    Hashtable otherAttrStartTables = new Hashtable();
    Hashtable otherAttrValueTables = new Hashtable();
    Hashtable otherTagTables = new Hashtable();
    
    String[] attrStartTable;
    String[] attrValueTable;
    String[] tagTable;
    String stringTable;
    
    int version;
    int publicIdentifierId;
    String publicIdentifier=null;
    int charSet;
    
    
    StartTag current;
    ParseEvent next;
    boolean whitespace;
    
    private PublicIDEntry documentPubID=null;
    private PublicIDEntry currentPubID=null;
    
    
    public WbxmlParser(InputStream in) throws Exception {
        
        int publicIdentifierOffset=-1;
        
        this.in = in;
        
        version = readByte();
        publicIdentifierId = readInt();
        
        if (publicIdentifierId == 0)
            publicIdentifierOffset=readInt();
        
        charSet = readInt(); // skip charset
        
        int strTabSize = readInt();
        
        StringBuffer buf = new StringBuffer(strTabSize);
        
        for (int i = 0; i < strTabSize; i++)
            buf.append((char)readByte());
        
        stringTable = buf.toString();
        
        // initialisation of tables and public identifier objects
        WbxmlInitialiser initialiser=null;
        if(publicIdentifierId!=0) {
            initialiser=WbxmlInitialiserFactory.getInitialiserByPublicIdentifierCode(publicIdentifierId);
        }
        else {
            if(publicIdentifierOffset>=0) {
                extractInlinePublicID(publicIdentifierOffset);
                if (publicIdentifier!=null) {
                    initialiser=WbxmlInitialiserFactory.getInitialiserByPublicIdentifier(publicIdentifier);
                }
            }
        }
        if(initialiser!=null) {
            initialiser.initialise(this);
        }
        
        // load the public identifier
        if(publicIdentifier==null) {
            documentPubID=getPublicIDEntryByCode(publicIdentifierId);
        }
        else {
            documentPubID=getPublicIDEntry(publicIdentifier);
        }
        
    }
    
    private void extractInlinePublicID(int anOffset) {
        publicIdentifier=this.extractFromStrT(anOffset);
    }
    
    public ParseEvent peek() throws IOException {
        
        String s;
        
        if (next != null)
            return next;
        
        if (current != null && current.getDegenerated()) {
            next = new Tag
            (Xml.END_TAG, current,
            current.getNamespace(),
            current.getName());
            
            current = current.getParent();
            return next;
        }
        
        ParseEvent result = null;
        
        do {
            int id = in.read();
            
            switch (id) {
                case -1:
                    if (current != null)
                        throw new RuntimeException("unclosed elements: " + current);
                    
                    next = new ParseEvent(Xml.END_DOCUMENT, null);
                    break;
                    
                case Wbxml.SWITCH_PAGE:
                    int page = readByte();
                    switchPage(page);
                    break;
                    
                case Wbxml.END:
                    next = new Tag(Xml.END_TAG, current,
                    current.getNamespace(),
                    current.getName());
                    
                    current = current.getParent();
                    break;
                    
                case Wbxml.ENTITY:
                    next = new ParseEvent(Xml.TEXT, "" + (char)readInt());
                    break;
                    
                case Wbxml.STR_I: {
                    s = readStrI();
                    next = new ParseEvent(whitespace ? Xml.WHITESPACE : Xml.TEXT, s);
                    break;
                }
                
                case Wbxml.EXT_I_0:
                case Wbxml.EXT_I_1:
                case Wbxml.EXT_I_2:
                case Wbxml.EXT_T_0:
                case Wbxml.EXT_T_1:
                case Wbxml.EXT_T_2:
                case Wbxml.EXT_0:
                case Wbxml.EXT_1:
                case Wbxml.EXT_2:
                case Wbxml.OPAQUE:
                    next = parseWapExtension(id);
                    break;
                    
                case Wbxml.PI:
                    throw new RuntimeException("PI curr. not supp.");
                    // readPI;
                    // break;
                    
                case Wbxml.STR_T: {
                    int pos = readInt();
                    int end = stringTable.indexOf('\0', pos);
                    next = new ParseEvent
                    (Xml.TEXT, stringTable.substring(pos, end));
                    break;
                }
                
                default:
                    next = parseElement(id);
            }
        }
        while (next == null);
        
        return next;
    }
    
    public ParseEvent read() throws IOException {
        if (next == null)
            peek();
        ParseEvent result = next;
        next = null;
        return result;
    }
    
    
    /**
     * Switches to code page <code>page</code>
     *
     * @param page the page to switch to
     */
    private void switchPage(int page){
        Integer ipage = new Integer(page);
        attrStartTable = (String[]) otherAttrStartTables.get(ipage);
        attrValueTable = (String[]) otherAttrValueTables.get(ipage);
        tagTable = (String[]) otherTagTables.get(ipage);
        
        currentPubID=getPublicIDEntryByIndex(page);
    }
    
    /** For handling wap extensions in attributes, overwrite this
    method, call super and return a corresponding TextEvent. */
    
    public ParseEvent parseWapExtension(int id) throws IOException {
        
        switch (id) {
            case Wbxml.EXT_I_0:
            case Wbxml.EXT_I_1:
            case Wbxml.EXT_I_2:
                return new WapExtensionEvent(id, readStrI());
                
            case Wbxml.EXT_T_0:
            case Wbxml.EXT_T_1:
            case Wbxml.EXT_T_2:
                return new WapExtensionEvent(id, new Integer(readInt()));
                
            case Wbxml.EXT_0:
            case Wbxml.EXT_1:
            case Wbxml.EXT_2:
                return new WapExtensionEvent(id, null);
                
            case Wbxml.OPAQUE: {
                int len = readInt();
                byte[] buf = new byte[len];
                
                for (int i = 0; i < len; i++)   // enhance with blockread!
                    buf[i] = (byte)readByte();
                
                return new WapExtensionEvent(id, buf);
            } // case OPAQUE
        } // SWITCH
        
        throw new IOException("illegal id!");
    }
    
    public Vector readAttr() throws IOException {
        
        Vector result = new Vector();
        
        int id = readByte();
        
        while (id != 1) {
            
            String name = resolveId(attrStartTable, id);
            StringBuffer value;
            
            int cut = name.indexOf('=');
            
            if (cut == -1)
                value = new StringBuffer();
            else {
                value = new StringBuffer(name.substring(cut + 1));
                name = name.substring(0, cut);
            }