qdparser.java

用Java实现的免费XML解析器

package qdxml;

import java.io.*;
import java.util.*;

/** Quick and Dirty xml parser.  This parser is, like the SAX parser,
    an event based parser, but with much less functionality.  */
public class QDParser {
  private static int popMode(Stack st) {
    if(!st.empty())
      return ((Integer)st.pop()).intValue();
    else
      return PRE;
  }
  private final static int 
    TEXT = 1,
    ENTITY = 2,
    OPEN_TAG = 3,
    CLOSE_TAG = 4,
    START_TAG = 5,
    ATTRIBUTE_LVALUE = 6,
    ATTRIBUTE_EQUAL = 9,
    ATTRIBUTE_RVALUE = 10,
    QUOTE = 7,
    IN_TAG = 8,
    SINGLE_TAG = 12,
    COMMENT = 13,
    DONE = 11,
    DOCTYPE = 14,
    PRE = 15,
    CDATA = 16;
  public static void parse(DocHandler doc,Reader r) throws Exception {
    Stack st = new Stack();
    int depth = 0;
    int mode = PRE;
    int c = 0;
    int quotec = '"';
    depth = 0;
    StringBuffer sb = new StringBuffer();
    StringBuffer etag = new StringBuffer();
    String tagName = null;
    String lvalue = null;
    String rvalue = null;
    Hashtable attrs = null;
    st = new Stack();
    doc.startDocument();
    int line=1, col=0;
    boolean eol = false;
    while((c = r.read()) != -1) {

      // We need to map \r, \r\n, and \n to \n
      // See XML spec section 2.11
      if(c == '\n' && eol) {
        eol = false;
	continue;
      } else if(eol) {
        eol = false;
      } else if(c == '\n') {
        line++;
	col=0;
      } else if(c == '\r') {
        eol = true;
	c = '\n';
	line++;
	col=0;
      } else {
        col++;
      }

      if(mode == DONE) {
	doc.endDocument();
        return;

      // We are between tags collecting text.
      } else if(mode == TEXT) {
        if(c == '<') {
	  st.push(new Integer(mode));
	  mode = START_TAG;
	  if(sb.length() > 0) {
	    doc.text(sb.toString());
	    sb.setLength(0);
	  }
        } else if(c == '&') {
	  st.push(new Integer(mode));
	  mode = ENTITY;
	  etag.setLength(0);
	} else
	  sb.append((char)c);

      // we are processing a closing tag: e.g. </foo>
      } else if(mode == CLOSE_TAG) {
        if(c == '>') {
	  mode = popMode(st);
	  tagName = sb.toString();
	  sb.setLength(0);
	  depth--;
	  if(depth==0)
	    mode = DONE;
	  doc.endElement(tagName);
	} else {
	  sb.append((char)c);
	}

      // we are processing CDATA
      } else if(mode == CDATA) {
        if(c == '>'
	&& sb.toString().endsWith("]]")) {
	  sb.setLength(sb.length()-2);
	  doc.text(sb.toString());
	  sb.setLength(0);
	  mode = popMode(st);
	} else
	  sb.append((char)c);

      // we are processing a comment.  We are inside
      // the <!-- .... --> looking for the -->.
      } else if(mode == COMMENT) {
        if(c == '>'
	&& sb.toString().endsWith("--")) {
	  sb.setLength(0);
	  mode = popMode(st);
	} else
	  sb.append((char)c);

      // We are outside the root tag element
      } else if(mode == PRE) {
	if(c == '<') {
	  mode = TEXT;
	  st.push(new Integer(mode));
	  mode = START_TAG;
        }

      // We are inside one of these <? ... ?>
      // or one of these <!DOCTYPE ... >
      } else if(mode == DOCTYPE) {
	if(c == '>') {
	  mode = popMode(st);
	  if(mode == TEXT) mode = PRE;
	}

      // we have just seen a < and
      // are wondering what we are looking at
      // <foo>, </foo>, <!-- ... --->, etc.
      } else if(mode == START_TAG) {
        mode = popMode(st);
	if(c == '/') {
	  st.push(new Integer(mode));
	  mode = CLOSE_TAG;
	} else if (c == '?') {
	  mode = DOCTYPE;
        } else {
	  st.push(new Integer(mode));
	  mode = OPEN_TAG;
	  tagName = null;
	  attrs = new Hashtable();
	  sb.append((char)c);
        }

      // we are processing an entity, e.g. &lt;, &#187;, etc.
      } else if(mode == ENTITY) {
        if(c == ';') {
	  mode = popMode(st);
	  String cent = etag.toString();
	  etag.setLength(0);
	  if(cent.equals("lt"))
	    sb.append('<');
	  else if(cent.equals("gt"))
	    sb.append('>');
	  else if(cent.equals("amp"))
	    sb.append('&');
	  else if(cent.equals("quot"))
	    sb.append('"');
	  else if(cent.equals("apos"))
	    sb.append('\'');
	  // Could parse hex entities if we wanted to
	  //else if(cent.startsWith("#x"))
	    //sb.append((char)Integer.parseInt(cent.substring(2),16));
	  else if(cent.startsWith("#"))
	    sb.append((char)Integer.parseInt(cent.substring(1)));
	  // Insert custom entity definitions here
	  else
	    exc("Unknown entity: &"+cent+";",line,col);
	} else {
	  etag.append((char)c);
	}

      // we have just seen something like this:
      // <foo a="b"/
      // and are looking for the final >.
      } else if(mode == SINGLE_TAG) {
	if(tagName == null)
	  tagName = sb.toString();
        if(c != '>')
	  exc("Expected > for tag: <"+tagName+"/>",line,col);
	doc.startElement(tagName,attrs);
	doc.endElement(tagName);
	if(depth==0) {
	  doc.endDocument();
	  return;
	}
	sb.setLength(0);
	attrs = new Hashtable();
	tagName = null;
	mode = popMode(st);

      // we are processing something
      // like this <foo ... >.  It could
      // still be a <!-- ... --> or something.
      } else if(mode == OPEN_TAG) {
	if(c == '>') {
	  if(tagName == null)
            tagName = sb.toString();
	  sb.setLength(0);
	  depth++;
	  doc.startElement(tagName,attrs);
	  tagName = null;
	  attrs = new Hashtable();
	  mode = popMode(st);
	} else if(c == '/') {
	  mode = SINGLE_TAG;
	} else if(c == '-' && sb.toString().equals("!-")) {
	  mode = COMMENT;
	} else if(c == '[' && sb.toString().equals("![CDATA")) {
	  mode = CDATA;
	  sb.setLength(0);
	} else if(c == 'E' && sb.toString().equals("!DOCTYP")) {
	  sb.setLength(0);
	  mode = DOCTYPE;
	} else if(Character.isWhitespace((char)c)) {
	  tagName = sb.toString();
	  sb.setLength(0);
	  mode = IN_TAG;
	} else {
	  sb.append((char)c);
	}

      // We are processing the quoted right-hand side
      // of an element's attribute.
      } else if(mode == QUOTE) {
        if(c == quotec) {
	  rvalue = sb.toString();
	  sb.setLength(0);
	  attrs.put(lvalue,rvalue);
	  mode = IN_TAG;
	// See section the XML spec, section 3.3.3
	// on normalization processing.
	} else if(" \r\n\u0009".indexOf(c)>=0) {
	  sb.append(' ');
	} else if(c == '&') {
	  st.push(new Integer(mode));
	  mode = ENTITY;
	  etag.setLength(0);
	} else {
	  sb.append((char)c);
	}

      } else if(mode == ATTRIBUTE_RVALUE) {
        if(c == '"' || c == '\'') {
	  quotec = c;
	  mode = QUOTE;
	} else if(Character.isWhitespace((char)c)) {
	  ;
	} else {
	  exc("Error in attribute processing",line,col);
	}

      } else if(mode == ATTRIBUTE_LVALUE) {
        if(Character.isWhitespace((char)c)) {
	  lvalue = sb.toString();
	  sb.setLength(0);
	  mode = ATTRIBUTE_EQUAL;
	} else if(c == '=') {
	  lvalue = sb.toString();
	  sb.setLength(0);
	  mode = ATTRIBUTE_RVALUE;
	} else {
	  sb.append((char)c);
	}

      } else if(mode == ATTRIBUTE_EQUAL) {
        if(c == '=') {
	  mode = ATTRIBUTE_RVALUE;
	} else if(Character.isWhitespace((char)c)) {
	  ;
	} else {
	  exc("Error in attribute processing.",line,col);
	}

      } else if(mode == IN_TAG) {
	if(c == '>') {
	  mode = popMode(st);
	  doc.startElement(tagName,attrs);
	  depth++;
	  tagName = null;
	  attrs = new Hashtable();
	} else if(c == '/') {
	  mode = SINGLE_TAG;
        } else if(Character.isWhitespace((char)c)) {
	  ;
	} else {
	  mode = ATTRIBUTE_LVALUE;
	  sb.append((char)c);
	}
      }
    }
    if(mode == DONE)
      doc.endDocument();
    else
      exc("missing end tag",line,col);
  }
  private static void exc(String s,int line,int col)
    throws Exception
  {
    throw new Exception(s+" near line "+line+", column "+col);
  }
}