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Trang, a multi-format schema converter based on RELAX NG.
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package com.thaiopensource.relaxng.parse.sax;

import com.thaiopensource.relaxng.parse.Annotations;
import com.thaiopensource.relaxng.parse.CommentList;
import com.thaiopensource.relaxng.parse.Context;
import com.thaiopensource.relaxng.parse.DataPatternBuilder;
import com.thaiopensource.relaxng.parse.Div;
import com.thaiopensource.relaxng.parse.ElementAnnotationBuilder;
import com.thaiopensource.relaxng.parse.Grammar;
import com.thaiopensource.relaxng.parse.GrammarSection;
import com.thaiopensource.relaxng.parse.IllegalSchemaException;
import com.thaiopensource.relaxng.parse.Include;
import com.thaiopensource.relaxng.parse.IncludedGrammar;
import com.thaiopensource.relaxng.parse.ParsedPatternFuture;
import com.thaiopensource.relaxng.parse.SchemaBuilder;
import com.thaiopensource.relaxng.parse.Scope;
import com.thaiopensource.util.Localizer;
import com.thaiopensource.util.Uri;
import com.thaiopensource.xml.sax.AbstractLexicalHandler;
import com.thaiopensource.xml.sax.XmlBaseHandler;
import com.thaiopensource.xml.util.Naming;
import com.thaiopensource.xml.util.WellKnownNamespaces;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;

class SchemaParser,
        AnnotationsImpl extends Annotations>
        implements ParsedPatternFuture {
  private static final String relaxngURIPrefix =
          WellKnownNamespaces.RELAX_NG.substring(0, WellKnownNamespaces.RELAX_NG.lastIndexOf('/') + 1);
  static final String relaxng10URI = WellKnownNamespaces.RELAX_NG;
  private static final Localizer localizer = new Localizer(SchemaParser.class);

  private String relaxngURI;
  private final XMLReader xr;
  private final ErrorHandler eh;
  private final SchemaBuilder schemaBuilder;
  private Pattern startPattern;
  private Locator locator;
  private final XmlBaseHandler xmlBaseHandler = new XmlBaseHandler();
  private final ContextImpl context = new ContextImpl();

  private boolean hadError = false;

  private Map patternMap;
  private Map nameClassMap;

  static class PrefixMapping {
    final String prefix;
    final String uri;
    final PrefixMapping next;

    PrefixMapping(String prefix, String uri, PrefixMapping next) {
      this.prefix = prefix;
      this.uri = uri;
      this.next = next;
    }
  }

  static abstract class AbstractContext extends DtdContext implements Context {
    PrefixMapping prefixMapping;

    AbstractContext() {
      prefixMapping = new PrefixMapping("xml", WellKnownNamespaces.XML, null);
    }

    AbstractContext(AbstractContext context) {
      super(context);
      prefixMapping = context.prefixMapping;
    }

    public String resolveNamespacePrefix(String prefix) {
      for (PrefixMapping p = prefixMapping; p != null; p = p.next)
        if (p.prefix.equals(prefix))
          return p.uri;
      return null;
    }

    public Set prefixes() {
      Set set = new HashSet();
      for (PrefixMapping p = prefixMapping; p != null; p = p.next)
        set.add(p.prefix);
      return set;
    }

    public Context copy() {
      return new SavedContext(this);
    }
  }

  static class SavedContext extends AbstractContext {
    private final String baseUri;
    SavedContext(AbstractContext context) {
      super(context);
      this.baseUri = context.getBaseUri();
    }

    public String getBaseUri() {
      return baseUri;
    }
  }

  class ContextImpl extends AbstractContext {
    public String getBaseUri() {
      return xmlBaseHandler.getBaseUri();
    }
  }

  static interface CommentHandler {
    void comment(String value);
  }

  abstract class Handler implements ContentHandler, CommentHandler {
    CommentListImpl comments;

    CommentListImpl getComments() {
      CommentListImpl tem = comments;
      comments = null;
      return tem;
    }

    public void comment(String value) {
      if (comments == null)
        comments = schemaBuilder.makeCommentList();
      comments.addComment(value, makeLocation());
    }
    public void processingInstruction(String target, String date) { }
    public void skippedEntity(String name) { }
    public void ignorableWhitespace(char[] ch, int start, int len) { }
    public void startDocument() { }
    public void endDocument() { }
    public void startPrefixMapping(String prefix, String uri) {
      context.prefixMapping = new PrefixMapping(prefix, uri, context.prefixMapping);
    }

    public void endPrefixMapping(String prefix) {
      context.prefixMapping = context.prefixMapping.next;
    }

    public void setDocumentLocator(Locator loc) {
      locator = loc;
      xmlBaseHandler.setLocator(loc);
    }
  }

  abstract class State extends Handler {
    State parent;
    String nsInherit;
    String ns;
    String datatypeLibrary;
    Scope scope;
    Location startLocation;
    AnnotationsImpl annotations;

    void set() {
      xr.setContentHandler(this);
    }

    abstract State create();
    abstract State createChildState(String localName) throws SAXException;

    RootState toRootState() {
      return null;
    }

    NameClassChoiceState toNameClassChoiceState() {
      return null;
    }

    void setParent(State parent) {
      this.parent = parent;
      this.nsInherit = parent.getNs();
      this.datatypeLibrary = parent.datatypeLibrary;
      this.scope = parent.scope;
      this.startLocation = makeLocation();
      if (parent.comments != null) {
        annotations = schemaBuilder.makeAnnotations(parent.comments, getContext());
        parent.comments = null;
      }
      else if (parent.toRootState() != null)
        annotations = schemaBuilder.makeAnnotations(null, getContext());
    }

    String getNs() {
      return ns == null ? nsInherit : ns;
    }

    boolean isRelaxNGElement(String uri) throws SAXException {
      return uri.equals(relaxngURI);
    }

    public void startElement(String namespaceURI,
			     String localName,
			     String qName,
			     Attributes atts) throws SAXException {
      xmlBaseHandler.startElement();
      if (isRelaxNGElement(namespaceURI)) {
	State state = createChildState(localName);
	if (state == null) {
	  xr.setContentHandler(new Skipper(this));
	  return;
	}
	state.setParent(this);
	state.set();
	state.attributes(atts);
      }
      else {
	checkForeignElement();
        ForeignElementHandler feh = new ForeignElementHandler(this, getComments());
        feh.startElement(namespaceURI, localName, qName, atts);
	xr.setContentHandler(feh);
      }
    }

    public void endElement(String namespaceURI,
			   String localName,
			   String qName) throws SAXException {
      xmlBaseHandler.endElement();
      parent.set();
      end();
    }

    void setName(String name) throws SAXException {
      error("illegal_name_attribute");
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      error("illegal_attribute_ignored", name);
    }

    void endAttributes() throws SAXException {
    }

    void checkForeignElement() throws SAXException {
    }

    void attributes(Attributes atts) throws SAXException {
      int len = atts.getLength();
      for (int i = 0; i < len; i++) {
	String uri = atts.getURI(i);
	if (uri.length() == 0) {
	  String name = atts.getLocalName(i);
	  if (name.equals("name"))
	    setName(atts.getValue(i).trim());
	  else if (name.equals("ns"))
	    ns = atts.getValue(i);
	  else if (name.equals("datatypeLibrary")) {
	    datatypeLibrary = atts.getValue(i);
	    checkUri(datatypeLibrary);
	    if (!datatypeLibrary.equals("")
		&& !Uri.isAbsolute(datatypeLibrary))
	      error("relative_datatype_library");
	    if (Uri.hasFragmentId(datatypeLibrary))
	      error("fragment_identifier_datatype_library");
	    datatypeLibrary = Uri.escapeDisallowedChars(datatypeLibrary);
	  }
	  else
	    setOtherAttribute(name, atts.getValue(i));
	}
	else if (uri.equals(relaxngURI))
	  error("qualified_attribute", atts.getLocalName(i));
	else if (uri.equals(WellKnownNamespaces.XML)
		 && atts.getLocalName(i).equals("base"))
	  xmlBaseHandler.xmlBaseAttribute(atts.getValue(i));
        else {
          if (annotations == null)
            annotations = schemaBuilder.makeAnnotations(null, getContext());
          annotations.addAttribute(uri, atts.getLocalName(i), findPrefix(atts.getQName(i), uri),
                                   atts.getValue(i), startLocation);
        }
      }
      endAttributes();
    }

    abstract void end() throws SAXException;

    void endPatternChild(Pattern pattern) {
      // XXX cannot happen; throw exception
    }

    void endNameClassChild(NameClass nc) {
      // XXX cannot happen; throw exception
    }

    public void startDocument() { }
    public void endDocument() {
      if (comments != null && startPattern != null) {
        startPattern = schemaBuilder.commentAfterPattern(startPattern, comments);
        comments = null;
      }
    }

    public void characters(char[] ch, int start, int len) throws SAXException {
      for (int i = 0; i < len; i++) {
	switch(ch[start + i]) {
	case ' ':
	case '\r':
	case '\n':
	case '\t':
	  break;
	default:
	  error("illegal_characters_ignored");
	  break;
	}
      }
    }

    boolean isPatternNamespaceURI(String s) {
      return s.equals(relaxngURI);
    }

    void endForeignChild(ElementAnnotation ea) {
      if (annotations == null)
        annotations = schemaBuilder.makeAnnotations(null, getContext());
      annotations.addElement(ea);
    }

    void mergeLeadingComments() {
      if (comments != null) {
        if (annotations == null)
          annotations = schemaBuilder.makeAnnotations(comments, getContext());
        else
          annotations.addLeadingComment(comments);
        comments = null;
      }
    }
  }

  class ForeignElementHandler extends Handler {
    final State nextState;
    ElementAnnotationBuilder builder;
    final Stack> builderStack = new Stack>();
    StringBuffer textBuf;
    Location textLoc;

    ForeignElementHandler(State nextState, CommentListImpl comments) {
      this.nextState = nextState;
      this.comments = comments;
    }

    public void startElement(String namespaceURI, String localName,
                             String qName, Attributes atts) {
      flushText();
      if (builder != null)
        builderStack.push(builder);
      Location loc = makeLocation();
      builder = schemaBuilder.makeElementAnnotationBuilder(namespaceURI,
                                                           localName,
                                                           findPrefix(qName, namespaceURI),
                                                           loc,
                                                           getComments(),
                                                           getContext());
      int len = atts.getLength();
      for (int i = 0; i < len; i++) {
	String uri = atts.getURI(i);
        builder.addAttribute(uri, atts.getLocalName(i), findPrefix(atts.getQName(i), uri),
                             atts.getValue(i), loc);
      }
    }

    public void endElement(String namespaceURI, String localName,
                           String qName) {
      flushText();
      if (comments != null)
        builder.addComment(getComments());
      ElementAnnotation ea = builder.makeElementAnnotation();
      if (builderStack.empty()) {
        nextState.endForeignChild(ea);
        nextState.set();
      }
      else {
        builder = builderStack.pop();
        builder.addElement(ea);
      }
    }

    public void characters(char ch[], int start, int length) {
      if (textBuf == null)
        textBuf = new StringBuffer();
      textBuf.append(ch, start, length);
      if (textLoc == null)
        textLoc = makeLocation();
    }

    public void comment(String value) {
      flushText();
      super.comment(value);
    }

    void flushText() {
      if (textBuf != null && textBuf.length() != 0) {
        builder.addText(textBuf.toString(), textLoc, getComments());
        textBuf.setLength(0);
      }
      textLoc = null;
    }
  }

  class Skipper extends DefaultHandler implements CommentHandler {
    int level = 1;
    final State nextState;

    Skipper(State nextState) {
      this.nextState = nextState;
    }

    public void startElement(String namespaceURI,
			     String localName,
			     String qName,
			     Attributes atts) throws SAXException {
      ++level;
    }

    public void endElement(String namespaceURI,
			   String localName,
			   String qName) throws SAXException {
      if (--level == 0)
	nextState.set();
    }

    public void comment(String value) {
    }
  }

  abstract class EmptyContentState extends State {

    State createChildState(String localName) throws SAXException {
      error("expected_empty", localName);
      return null;
    }

    abstract Pattern makePattern() throws SAXException;

    void end() throws SAXException {
      if (comments != null) {
        if (annotations == null)
          annotations = schemaBuilder.makeAnnotations(null, getContext());
        annotations.addComment(comments);
        comments = null;
      }
      parent.endPatternChild(makePattern());
    }
  }

  abstract class PatternContainerState extends State {
    List childPatterns = new ArrayList();

    State createChildState(String localName) throws SAXException {
      State state = patternMap.get(localName);
      if (state == null) {
	error("expected_pattern", localName);
	return null;
      }
      return state.create();
    }

    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      if (patterns.size() == 1 && anno == null)
        return patterns.get(0);
      return schemaBuilder.makeGroup(patterns, loc, anno);
    }

    void endPatternChild(Pattern pattern) {
      childPatterns.add(pattern);
    }

    void endForeignChild(ElementAnnotation ea) {
      int nChildPatterns = childPatterns.size();
      if (nChildPatterns == 0)
        super.endForeignChild(ea);
      else
        childPatterns.set(nChildPatterns - 1,
                          schemaBuilder.annotateAfterPattern(childPatterns.get(nChildPatterns - 1), ea));
    }

    void end() throws SAXException {
      if (childPatterns.size() == 0) {
	error("missing_children");
	endPatternChild(schemaBuilder.makeErrorPattern());
      }
      if (comments != null) {
        int nChildPatterns = childPatterns.size();
        childPatterns.set(nChildPatterns - 1,
                          schemaBuilder.commentAfterPattern(childPatterns.get(nChildPatterns - 1), comments));
        comments = null;
      }
      sendPatternToParent(buildPattern(childPatterns, startLocation, annotations));
    }

    void sendPatternToParent(Pattern p) {
      parent.endPatternChild(p);
    }
  }

  class GroupState extends PatternContainerState {
    State create() {
      return new GroupState();
    }
  }

  class ZeroOrMoreState extends PatternContainerState {
    State create() {
      return new ZeroOrMoreState();
    }

    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeZeroOrMore(super.buildPattern(patterns, loc, null), loc, anno);
    }
  }

  class OneOrMoreState extends PatternContainerState {
    State create() {
      return new OneOrMoreState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeOneOrMore(super.buildPattern(patterns, loc, null), loc, anno);
    }
  }

  class OptionalState extends PatternContainerState {
    State create() {
      return new OptionalState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeOptional(super.buildPattern(patterns, loc, null), loc, anno);
    }
  }

  class ListState extends PatternContainerState {
    State create() {
      return new ListState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeList(super.buildPattern(patterns, loc, null), loc, anno);
    }
  }

  class ChoiceState extends PatternContainerState {
    State create() {
      return new ChoiceState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeChoice(patterns, loc, anno);
    }
  }

  class InterleaveState extends PatternContainerState {
    State create() {
      return new InterleaveState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) {
      return schemaBuilder.makeInterleave(patterns, loc, anno);
    }
  }

  class MixedState extends PatternContainerState {
    State create() {
      return new MixedState();
    }
    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeMixed(super.buildPattern(patterns, loc, null), loc, anno);
    }
  }

  static interface NameClassRef {
    void setNameClass(NC nc);
  }

  class ElementState extends PatternContainerState implements NameClassRef {
    NameClass nameClass;
    boolean nameClassWasAttribute;
    String name;

    void setName(String name) {
      this.name = name;
    }

    public void setNameClass(NameClass nc) {
      nameClass = nc;
    }

    void endAttributes() throws SAXException {
      if (name != null) {
	nameClass = expandName(name, getNs(), null);
        nameClassWasAttribute = true;
      }
      else
	new NameClassChildState(this, this).set();
    }

    State create() {
      return new ElementState();
    }

    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeElement(nameClass, super.buildPattern(patterns, loc, null), loc, anno);
    }

    void endForeignChild(ElementAnnotation ea) {
      if (nameClassWasAttribute || childPatterns.size() > 0 || nameClass == null)
        super.endForeignChild(ea);
      else
        nameClass = schemaBuilder.annotateAfterNameClass(nameClass, ea);
    }
  }

  class RootState extends PatternContainerState {
    IncludedGrammar grammar;

    RootState() {
    }

    RootState(IncludedGrammar grammar, Scope scope, String ns) {
      this.grammar = grammar;
      this.scope = scope;
      this.nsInherit = ns;
      this.datatypeLibrary = "";
    }

    RootState toRootState() {
      return this;
    }

    State create() {
      return new RootState();
    }

    State createChildState(String localName) throws SAXException {
      if (grammar == null)
	return super.createChildState(localName);
      if (localName.equals("grammar"))
	return new MergeGrammarState(grammar);
      error("expected_grammar", localName);
      return null;
    }

    void checkForeignElement() throws SAXException {
      error("root_bad_namespace_uri", WellKnownNamespaces.RELAX_NG);
    }

    void endPatternChild(Pattern pattern) {
      startPattern = pattern;
    }

    boolean isRelaxNGElement(String uri) throws SAXException {
      if (!uri.startsWith(relaxngURIPrefix))
	return false;
      if (!uri.equals(WellKnownNamespaces.RELAX_NG))
	warning("wrong_uri_version",
		WellKnownNamespaces.RELAX_NG.substring(relaxngURIPrefix.length()),
		uri.substring(relaxngURIPrefix.length()));
      relaxngURI = uri;
      return true;
    }

  }

  class NotAllowedState extends EmptyContentState {
    State create() {
      return new NotAllowedState();
    }

    Pattern makePattern() {
      return schemaBuilder.makeNotAllowed(startLocation, annotations);
    }
  }

  class EmptyState extends EmptyContentState {
    State create() {
      return new EmptyState();
    }

    Pattern makePattern() {
      return schemaBuilder.makeEmpty(startLocation, annotations);
    }
  }

  class TextState extends EmptyContentState {
    State create() {
      return new TextState();
    }

    Pattern makePattern() {
      return schemaBuilder.makeText(startLocation, annotations);
    }
  }

  class ValueState extends EmptyContentState {
    final StringBuffer buf = new StringBuffer();
    String type;

    State create() {
      return new ValueState();
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      if (name.equals("type"))
	type = checkNCName(value.trim());
      else
	super.setOtherAttribute(name, value);
    }

    public void characters(char[] ch, int start, int len) {
      buf.append(ch, start, len);
    }

    void checkForeignElement() throws SAXException {
      error("value_contains_foreign_element");
    }

    Pattern makePattern() throws SAXException {
      if (type == null)
        return makePattern("", "token");
      else
        return makePattern(datatypeLibrary, type);
    }

    void end() throws SAXException {
      mergeLeadingComments();
      super.end();
    }

    Pattern makePattern(String datatypeLibrary, String type) {
      return schemaBuilder.makeValue(datatypeLibrary,
                                     type,
                                     buf.toString(),
                                     getContext(),
                                     getNs(),
                                     startLocation,
                                     annotations);
    }

  }

  class DataState extends State {
    String type;
    Pattern except = null;
    DataPatternBuilder dpb = null;

    State create() {
      return new DataState();
    }

    State createChildState(String localName) throws SAXException {
      if (localName.equals("param")) {
	if (except != null)
	  error("param_after_except");
	return new ParamState(dpb);
      }
      if (localName.equals("except")) {
	if (except != null)
	  error("multiple_except");
	return new ChoiceState();
      }
      error("expected_param_except", localName);
      return null;
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      if (name.equals("type"))
	type = checkNCName(value.trim());
      else
	super.setOtherAttribute(name, value);
    }

    void endAttributes() throws SAXException {
      if (type == null)
	error("missing_type_attribute");
      else
	dpb = schemaBuilder.makeDataPatternBuilder(datatypeLibrary, type, startLocation);
    }

    void endForeignChild(ElementAnnotation ea) {
      dpb.annotation(ea);
    }

    void end() throws SAXException {
      Pattern p;
      if (dpb != null) {
        if (except != null)
          p = dpb.makePattern(except, startLocation, annotations);
        else
          p = dpb.makePattern(startLocation, annotations);
      }
      else
        p = schemaBuilder.makeErrorPattern();
      // XXX need to capture comments
      parent.endPatternChild(p);
    }

    void endPatternChild(Pattern pattern) {
      except = pattern;
    }

  }

  class ParamState extends State {
    private final StringBuffer buf = new StringBuffer();
    private final DataPatternBuilder dpb;
    private String name;

    ParamState(DataPatternBuilder dpb) {
      this.dpb = dpb;
    }

    State create() {
      return new ParamState(null);
    }

    void setName(String name) throws SAXException {
      this.name = checkNCName(name);
    }

    void endAttributes() throws SAXException {
      if (name == null)
	error("missing_name_attribute");
    }

    State createChildState(String localName) throws SAXException {
      error("expected_empty", localName);
      return null;
    }

    public void characters(char[] ch, int start, int len) {
      buf.append(ch, start, len);
    }

    void checkForeignElement() throws SAXException {
      error("param_contains_foreign_element");
    }

    void end() throws SAXException {
      if (name == null)
	return;
      if (dpb == null)
        return;
      mergeLeadingComments();
      dpb.addParam(name, buf.toString(), getContext(), getNs(), startLocation, annotations);
    }
  }

  class AttributeState extends PatternContainerState implements NameClassRef {
    NameClass nameClass;
    boolean nameClassWasAttribute;
    String name;

    State create() {
      return new AttributeState();
    }

    void setName(String name) {
      this.name = name;
    }

    public void setNameClass(NameClass nc) {
      nameClass = nc;
    }

    void endAttributes() throws SAXException {
      if (name != null) {
	String nsUse;
	if (ns != null)
	  nsUse = ns;
	else
	  nsUse = "";
	nameClass = expandName(name, nsUse, null);
        nameClassWasAttribute = true;
      }
      else
	new NameClassChildState(this, this).set();
    }

    void endForeignChild(ElementAnnotation ea) {
      if (nameClassWasAttribute || childPatterns.size() > 0 || nameClass == null)
        super.endForeignChild(ea);
      else
        nameClass = schemaBuilder.annotateAfterNameClass(nameClass, ea);
    }

    void end() throws SAXException {
      if (childPatterns.size() == 0)
	endPatternChild(schemaBuilder.makeText(startLocation, null));
      super.end();
    }

    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return schemaBuilder.makeAttribute(nameClass, super.buildPattern(patterns, loc, null), loc, anno);
    }

    State createChildState(String localName) throws SAXException {
      State tem = super.createChildState(localName);
      if (tem != null && childPatterns.size() != 0)
	error("attribute_multi_pattern");
      return tem;
    }

  }

  abstract class SinglePatternContainerState extends PatternContainerState {
    State createChildState(String localName) throws SAXException {
      if (childPatterns.size() == 0)
	return super.createChildState(localName);
      error("too_many_children");
      return null;
    }
  }

  class GrammarSectionState extends State {
    GrammarSection section;

    GrammarSectionState() { }

    GrammarSectionState(GrammarSection section) {
      this.section = section;
    }

    State create() {
      return new GrammarSectionState(null);
    }

    State createChildState(String localName) throws SAXException {
      if (localName.equals("define"))
	return new DefineState(section);
      if (localName.equals("start"))
	return new StartState(section);
      if (localName.equals("include")) {
	Include include = section.makeInclude();
	if (include != null)
	  return new IncludeState(include);
      }
      if (localName.equals("div"))
	return new DivState(section.makeDiv());
      error("expected_define", localName);
      // XXX better errors
      return null;
    }

    void end() throws SAXException {
      if (comments != null) {
        section.topLevelComment(comments);
        comments = null;
      }
    }

    void endForeignChild(ElementAnnotation ea) {
      section.topLevelAnnotation(ea);
    }
  }

  class DivState extends GrammarSectionState {
    final Div div;
    DivState(Div div) {
      super(div);
      this.div = div;
    }

    void end() throws SAXException {
      super.end();
      div.endDiv(startLocation, annotations);
    }
  }

  class IncludeState extends GrammarSectionState {
    String href;
    String base;
    final Include include;

    IncludeState(Include include) {
      super(include);
      this.include = include;
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      if (name.equals("href")) {
	href = value;
	checkUriNoFragmentId(href);
      }
      else
	super.setOtherAttribute(name, value);
    }

    void endAttributes() throws SAXException {
      if (href == null)
	error("missing_href_attribute");
      else
        base = xmlBaseHandler.getBaseUri();
    }

    void end() throws SAXException {
      super.end();
      if (href != null) {
        try {
          include.endInclude(href, base, getNs(), startLocation, annotations);
        }
        catch (IllegalSchemaException e) {
        }
      }
    }
  }

  class MergeGrammarState extends GrammarSectionState {
    final IncludedGrammar grammar;
    MergeGrammarState(IncludedGrammar grammar) {
      super(grammar);
      this.grammar = grammar;
    }

    void end() throws SAXException {
      super.end();
      parent.endPatternChild(grammar.endIncludedGrammar(startLocation, annotations));
    }
  }

  class GrammarState extends GrammarSectionState {
    Grammar grammar;

    void setParent(State parent) {
      super.setParent(parent);
      grammar = schemaBuilder.makeGrammar(scope);
      section = grammar;
      scope = grammar;
    }

    State create() {
      return new GrammarState();
    }

    void end() throws SAXException {
      super.end();
      parent.endPatternChild(grammar.endGrammar(startLocation, annotations));
    }
  }

  class RefState extends EmptyContentState {
    String name;

    State create() {
      return new RefState();
    }

    void endAttributes() throws SAXException {
      if (name == null)
	error("missing_name_attribute");
    }

    void setName(String name) throws SAXException {
      this.name = checkNCName(name);
    }

    Pattern makePattern() {
      if (name == null)
        return schemaBuilder.makeErrorPattern();
      return scope.makeRef(name, startLocation, annotations);
    }
  }

  class ParentRefState extends RefState {
    State create() {
      return new ParentRefState();
    }

    Pattern makePattern() {
      if (name == null)
        return schemaBuilder.makeErrorPattern();
      return scope.makeParentRef(name, startLocation, annotations);
    }
  }

  class ExternalRefState extends EmptyContentState {
    String href;
    String base;
    Pattern includedPattern;

    State create() {
      return new ExternalRefState();
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      if (name.equals("href")) {
	href = value;
	checkUriNoFragmentId(href);
      }
      else
	super.setOtherAttribute(name, value);
    }

    void endAttributes() throws SAXException {
      if (href == null)
	error("missing_href_attribute");
      else
        base = xmlBaseHandler.getBaseUri();
    }

    Pattern makePattern() {
      if (href != null) {
        try {
          return schemaBuilder.makeExternalRef(href,
                                               base,
                                               getNs(),
                                               scope,
                                               startLocation,
                                               annotations);
        }
        catch (IllegalSchemaException e) { }
      }
      return schemaBuilder.makeErrorPattern();
    }
  }

  abstract class DefinitionState extends PatternContainerState {
    GrammarSection.Combine combine = null;
    final GrammarSection section;

    DefinitionState(GrammarSection section) {
      this.section = section;
    }

    void setOtherAttribute(String name, String value) throws SAXException {
      if (name.equals("combine")) {
	value = value.trim();
	if (value.equals("choice"))
	  combine = GrammarSection.COMBINE_CHOICE;
	else if (value.equals("interleave"))
	  combine = GrammarSection.COMBINE_INTERLEAVE;
	else
	  error("combine_attribute_bad_value", value);
      }
      else
	super.setOtherAttribute(name, value);
    }

    Pattern buildPattern(List patterns, Location loc, AnnotationsImpl anno) throws SAXException {
      return super.buildPattern(patterns, loc, null);
    }
  }

  class DefineState extends DefinitionState {
    String name;

    DefineState(GrammarSection section) {
      super(section);
    }

    State create() {
      return new DefineState(null);
    }

    void setName(String name) throws SAXException {
      this.name = checkNCName(name);
    }

    void endAttributes() throws SAXException {
      if (name == null)
	error("missing_name_attribute");
    }

    void sendPatternToParent(Pattern p) {
      if (name != null)
	section.define(name, combine, p, startLocation, annotations);
    }

  }

  class StartState extends DefinitionState {

    StartState(GrammarSection section) {
      super(section);
    }

    State create() {
      return new StartState(null);
    }

    void sendPatternToParent(Pattern p) {
      section.define(GrammarSection.START, combine, p, startLocation, annotations);
    }

    State createChildState(String localName) throws SAXException {
      State tem = super.createChildState(localName);
      if (tem != null && childPatterns.size() != 0)
	error("start_multi_pattern");
      return tem;
    }

  }

  abstract class NameClassContainerState extends State {
    State createChildState(String localName) throws SAXException {
      State state = nameClassMap.get(localName);
      if (state == null) {
	error("expected_name_class", localName);
	return null;
      }
      return state.create();
    }
  }

  class NameClassChildState extends NameClassContainerState {
    final State prevState;
    final NameClassRef nameClassRef;

    State create() {
      return null;
    }

    NameClassChildState(State prevState, NameClassRef nameClassRef) {
      this.prevState = prevState;
      this.nameClassRef = nameClassRef;
      setParent(prevState.parent);
      this.ns = prevState.ns;
    }

    void endNameClassChild(NameClass nameClass) {
      nameClassRef.setNameClass(nameClass);
      prevState.set();
    }

    void endForeignChild(ElementAnnotation ea) {
      prevState.endForeignChild(ea);
    }

    void end() throws SAXException {
      nameClassRef.setNameClass(schemaBuilder.makeErrorNameClass());
      error("missing_name_class");
      prevState.set();
      prevState.end();
    }
  }

  abstract class NameClassBaseState extends State {

    abstract NameClass makeNameClass() throws SAXException;

    void end() throws SAXException {
      parent.endNameClassChild(makeNameClass());
    }
  }

  class NameState extends NameClassBaseState {
    final StringBuffer buf = new StringBuffer();

    State createChildState(String localName) throws SAXException {
      error("expected_name", localName);
      return null;
    }

    State create() {
      return new NameState();
    }

    public void characters(char[] ch, int start, int len) {
      buf.append(ch, start, len);
    }

    void checkForeignElement() throws SAXException {
      error("name_contains_foreign_element");
    }

    NameClass makeNameClass() throws SAXException {
      mergeLeadingComments();
      return expandName(buf.toString().trim(), getNs(), annotations);
    }

  }

  private static final int PATTERN_CONTEXT = 0;
  private static final int ANY_NAME_CONTEXT = 1;
  private static final int NS_NAME_CONTEXT = 2;

  class AnyNameState extends NameClassBaseState {
    NameClass except = null;

    State create() {
      return new AnyNameState();
    }

    State createChildState(String localName) throws SAXException {
      if (localName.equals("except")) {
	if (except != null)
	  error("multiple_except");
	return new NameClassChoiceState(getContext());
      }
      error("expected_except", localName);
      return null;
    }

    int getContext() {
      return ANY_NAME_CONTEXT;
    }

    NameClass makeNameClass() {
      if (except == null)
	return makeNameClassNoExcept();
      else
	return makeNameClassExcept(except);
    }

    NameClass makeNameClassNoExcept() {
      return schemaBuilder.makeAnyName(startLocation, annotations);
    }

    NameClass makeNameClassExcept(NameClass except) {
      return schemaBuilder.makeAnyName(except, startLocation, annotations);
    }

    void endNameClassChild(NameClass nameClass) {
      except = nameClass;
    }

  }

  class NsNameState extends AnyNameState {
    State create() {
      return new NsNameState();
    }

    NameClass makeNameClassNoExcept() {
      return schemaBuilder.makeNsName(getNs(), null, null);
    }

    NameClass makeNameClassExcept(NameClass except) {
      return schemaBuilder.makeNsName(getNs(), except, null, null);
    }

    int getContext() {
      return NS_NAME_CONTEXT;
    }

  }

  class NameClassChoiceState extends NameClassContainerState {
    private List nameClasses = new ArrayList();
    private int context;

    NameClassChoiceState() {
      this.context = PATTERN_CONTEXT;
    }

    NameClassChoiceState(int context) {
      this.context = context;
    }

    NameClassChoiceState toNameClassChoiceState() {
      return this;
    }

    void setParent(State parent) {
      super.setParent(parent);
      NameClassChoiceState parentChoice = parent.toNameClassChoiceState();
      if (parentChoice != null)
	this.context = parentChoice.context;
    }

    State create() {
      return new NameClassChoiceState();
    }

    State createChildState(String localName) throws SAXException {
      if (localName.equals("anyName")) {
	if (context >= ANY_NAME_CONTEXT) {
	  error(context == ANY_NAME_CONTEXT
		? "any_name_except_contains_any_name"
		: "ns_name_except_contains_any_name");
	  return null;
	}
      }
      else if (localName.equals("nsName")) {
	if (context == NS_NAME_CONTEXT) {
	  error("ns_name_except_contains_ns_name");
	  return null;
	}
      }
      return super.createChildState(localName);
    }

    void endNameClassChild(NameClass nc) {
      nameClasses.add(nc);
    }

    void endForeignChild(ElementAnnotation ea) {
      int nNameClasses = nameClasses.size();
      if (nNameClasses == 0)
        super.endForeignChild(ea);
      else
        nameClasses.set(nNameClasses - 1,
                        schemaBuilder.annotateAfterNameClass(nameClasses.get(nNameClasses - 1), ea));
    }

    void end() throws SAXException {
      if (nameClasses.size() == 0) {
	error("missing_name_class");
	parent.endNameClassChild(schemaBuilder.makeErrorNameClass());
	return;
      }
      if (comments != null) {
        int nNameClasses = nameClasses.size();
        nameClasses.set(nNameClasses - 1,
                        schemaBuilder.commentAfterNameClass(nameClasses.get(nNameClasses - 1), comments));
        comments = null;
      }
      parent.endNameClassChild(schemaBuilder.makeNameClassChoice(nameClasses, startLocation, annotations));
    }
  }

  private void initPatternTable() {
    patternMap = new HashMap();
    patternMap.put("zeroOrMore", new ZeroOrMoreState());
    patternMap.put("oneOrMore", new OneOrMoreState());
    patternMap.put("optional", new OptionalState());
    patternMap.put("list", new ListState());
    patternMap.put("choice", new ChoiceState());
    patternMap.put("interleave", new InterleaveState());
    patternMap.put("group", new GroupState());
    patternMap.put("mixed", new MixedState());
    patternMap.put("element", new ElementState());
    patternMap.put("attribute", new AttributeState());
    patternMap.put("empty", new EmptyState());
    patternMap.put("text", new TextState());
    patternMap.put("value", new ValueState());
    patternMap.put("data", new DataState());
    patternMap.put("notAllowed", new NotAllowedState());
    patternMap.put("grammar", new GrammarState());
    patternMap.put("ref", new RefState());
    patternMap.put("parentRef", new ParentRefState());
    patternMap.put("externalRef", new ExternalRefState());
  }

  private void initNameClassTable() {
    nameClassMap = new HashMap();
    nameClassMap.put("name", new NameState());
    nameClassMap.put("anyName", new AnyNameState());
    nameClassMap.put("nsName", new NsNameState());
    nameClassMap.put("choice", new NameClassChoiceState());
  }

  public Pattern getParsedPattern() throws IllegalSchemaException {
    if (hadError)
      throw new IllegalSchemaException();
    return startPattern;
  }

  private void error(String key) throws SAXException {
    error(key, locator);
  }

  private void error(String key, String arg) throws SAXException {
    error(key, arg, locator);
  }

  void error(String key, String arg1, String arg2) throws SAXException {
    error(key, arg1, arg2, locator);
  }

  private void error(String key, Locator loc) throws SAXException {
    error(new SAXParseException(localizer.message(key), loc));
  }

  private void error(String key, String arg, Locator loc) throws SAXException {
    error(new SAXParseException(localizer.message(key, arg), loc));
  }

  private void error(String key, String arg1, String arg2, Locator loc)
    throws SAXException {
    error(new SAXParseException(localizer.message(key, arg1, arg2), loc));
  }

  private void error(SAXParseException e) throws SAXException {
    hadError = true;
    if (eh != null)
      eh.error(e);
  }

  void warning(String key) throws SAXException {
    warning(key, locator);
  }

  private void warning(String key, String arg) throws SAXException {
    warning(key, arg, locator);
  }

  private void warning(String key, String arg1, String arg2) throws SAXException {
    warning(key, arg1, arg2, locator);
  }

  private void warning(String key, Locator loc) throws SAXException {
    warning(new SAXParseException(localizer.message(key), loc));
  }

  private void warning(String key, String arg, Locator loc) throws SAXException {
    warning(new SAXParseException(localizer.message(key, arg), loc));
  }

  private void warning(String key, String arg1, String arg2, Locator loc)
    throws SAXException {
    warning(new SAXParseException(localizer.message(key, arg1, arg2), loc));
  }

  private void warning(SAXParseException e) throws SAXException {
    if (eh != null)
      eh.warning(e);
  }

  SchemaParser(XMLReader xr,
               ErrorHandler eh,
               SchemaBuilder schemaBuilder,
               IncludedGrammar grammar,
               Scope scope) throws SAXException {
    this.xr = xr;
    this.eh = eh;
    this.schemaBuilder = schemaBuilder;
    if (eh != null)
      xr.setErrorHandler(eh);
    xr.setDTDHandler(context);
    if (schemaBuilder.usesComments()) {
      try {
        xr.setProperty("http://xml.org/sax/properties/lexical-handler", new LexicalHandlerImpl());
      }
      catch (SAXNotRecognizedException e) {
        warning("no_comment_support", xr.getClass().getName());
      }
      catch (SAXNotSupportedException e) {
        warning("no_comment_support", xr.getClass().getName());
      }
    }
    initPatternTable();
    initNameClassTable();
    new RootState(grammar, scope, SchemaBuilder.INHERIT_NS).set();
  }


  private Context getContext() {
    return context;
  }

  class LexicalHandlerImpl extends AbstractLexicalHandler {
    private boolean inDtd = false;

    public void startDTD(String s, String s1, String s2) throws SAXException {
      inDtd = true;
    }

    public void endDTD() throws SAXException {
      inDtd = false;
    }

    public void comment(char[] chars, int start, int length) throws SAXException {
      if (!inDtd)
        ((CommentHandler)xr.getContentHandler()).comment(new String(chars, start, length));
    }
  }

  private NameClass expandName(String name, String ns, AnnotationsImpl anno) throws SAXException {
    int ic = name.indexOf(':');
    if (ic == -1)
      return schemaBuilder.makeName(ns, checkNCName(name), null, null, anno);
    String prefix = checkNCName(name.substring(0, ic));
    String localName = checkNCName(name.substring(ic + 1));
    for (PrefixMapping tem = context.prefixMapping; tem != null; tem = tem.next)
      if (tem.prefix.equals(prefix))
	return schemaBuilder.makeName(tem.uri, localName, prefix, null, anno);
    error("undefined_prefix", prefix);
    return schemaBuilder.makeName("", localName, null, null, anno);
  }

  private String findPrefix(String qName, String uri) {
    String prefix = null;
    if (qName == null || qName.equals("")) {
      for (PrefixMapping p = context.prefixMapping; p != null; p = p.next)
        if (p.uri.equals(uri)) {
          prefix = p.prefix;
          break;
        }
    }
    else {
      int off = qName.indexOf(':');
      if (off > 0)
        prefix = qName.substring(0, off);
    }
    return prefix;
  }
  private String checkNCName(String str) throws SAXException {
    if (!Naming.isNcname(str))
      error("invalid_ncname", str);
    return str;
  }

  private Location makeLocation() {
    if (locator == null)
      return null;
    return schemaBuilder.makeLocation(locator.getSystemId(),
				      locator.getLineNumber(),
				      locator.getColumnNumber());
  }

  private void checkUriNoFragmentId(String s) throws SAXException {
    checkUri(s);
    if (Uri.hasFragmentId(s))
      error("href_fragment_id");
  }

  private void checkUri(String s) throws SAXException {
    if (!Uri.isValid(s))
      error("invalid_uri", s);
  }
}