/**
    * Redistribution and use of this software and associated documentation ("Software"), with or
    * without modification, are permitted provided that the following conditions are met:
    *
    * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
    * must also contain a copy of this document.
    *
    * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
    * conditions and the following disclaimer in the documentation and/or other materials provided with
   * the distribution.
   *
   * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
   * without prior written permission of Intalio, Inc. For written permission, please contact
   * info@exolab.org.
   *
   * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
   * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
   * Intalio, Inc.
   *
   * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
   *
   * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
   * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * Copyright 2004 (C) Intalio, Inc. All Rights Reserved.
   *
   * $Id$
   */
  
  package org.exolab.castor.xml.schema.reader;
  
  import org.exolab.castor.net.URILocation;
  import org.exolab.castor.net.URIResolver;
  import org.exolab.castor.xml.AttributeSet;
  import org.exolab.castor.xml.Namespaces;
  import org.exolab.castor.xml.XMLException;
  import org.exolab.castor.xml.schema.Annotation;
  import org.exolab.castor.xml.schema.AttributeGroup;
  import org.exolab.castor.xml.schema.AttributeGroupDecl;
  import org.exolab.castor.xml.schema.ComplexType;
  import org.exolab.castor.xml.schema.Group;
  import org.exolab.castor.xml.schema.ModelGroup;
  import org.exolab.castor.xml.schema.RedefineSchema;
  import org.exolab.castor.xml.schema.Schema;
  import org.exolab.castor.xml.schema.SchemaContext;
  import org.exolab.castor.xml.schema.SchemaException;
  import org.exolab.castor.xml.schema.SchemaNames;
  import org.exolab.castor.xml.schema.SimpleType;
  import org.exolab.castor.xml.schema.XMLType;
  import org.xml.sax.Locator;
  import org.xml.sax.Parser;
  
  /**
   * The purpose of this class is to read redefined elements in an XML schema. The following xml
   * schema structure can be redefined:
   * <ul>
   * <li>Complextypes</li>
   * <li>Simpletypes</li>
   * <li>AttributeGroup</li>
   * <li>Group</li>
   * </ul>
   * 
   * @author <a href="mailto:blandin@intalio.com">Arnaud Blandin</a>
   * @version $Revision$ $Date: 2006-04-25 15:08:23 -0600 (Tue, 25 Apr 2006) $
   **/
  public class RedefineUnmarshaller extends ComponentReader {
  
    /**
     * The current ComponentReader used to read nested structures
     **/
    private ComponentReader _unmarshaller;
  
    /**
     * The current branch depth
     **/
    private int _depth = 0;
  
    /**
     * The parent XML schema
     */
    private Schema _schema;
  
    /**
     * The imported XML Schema
     */
    private Schema _importedSchema;
  
    private RedefineSchema _redefineSchema;
  
    /**
     * The XML Schema imported
     */
  
   public RedefineUnmarshaller(final SchemaContext schemaContext, final Schema schema,
       final AttributeSet atts, final URIResolver uriResolver, final Locator locator,
       final SchemaUnmarshallerState state) throws XMLException {
     super(schemaContext);
     if (schema == null) {
       String err = SchemaNames.REDEFINE + " must be used with an existing parent XML Schema.";
       throw new SchemaException(err);
     }
     setURIResolver(uriResolver);
 
     URILocation uri = null;
     // -- Get schemaLocation
     String schemaLocation = atts.getValue(SchemaNames.SCHEMALOCATION_ATTR);
     _schema = schema;
 
     if (schemaLocation == null) {
       // -- <redefine/> or <redefine> <annotation>(*) </redefine>
       _redefineSchema = new RedefineSchema(schema);
       _schema.addRedefineSchema(_redefineSchema);
       return;
     }
 
 
     if (schemaLocation.indexOf("\\") != -1) {
       String err = "'" + schemaLocation + "' is not a valid URI as defined by IETF RFC 2396.";
       err += "The URI mustn't contain '\\'.";
       error(err);
     }
 
     uri = derive(locator, schemaLocation);
     if (uri != null) {
       schemaLocation = uri.getAbsoluteURI();
     }
 
     // -- Schema object to hold import schema
     boolean addSchema = false;
     _redefineSchema = schema.getRedefineSchema(schemaLocation);
     Schema importedSchema = null;
 
     boolean alreadyLoaded = false;
 
     // -- The schema is not yet loaded
     if (_redefineSchema == null) {
       if (uri instanceof SchemaLocation) {
         importedSchema = ((SchemaLocation) uri).getSchema();
         // -- set the main schema in order to handle
         // -- redefinition at runtime
 
         // importedSchema.addMainSchema(schema);
 
         _redefineSchema = new RedefineSchema(schema, importedSchema);
         schema.addRedefineSchema(_redefineSchema);
         alreadyLoaded = true;
       } else {
         importedSchema = new Schema();
         addSchema = true;
       }
     } else {
       // -- check schema location, if different, allow merge
       String tmpLocation = _redefineSchema.getOriginalSchema().getSchemaLocation();
       alreadyLoaded = schemaLocation.equals(tmpLocation);
     }
 
     state.markAsProcessed(schemaLocation, importedSchema);
 
     if (alreadyLoaded)
       return;
 
     // -- Parser Schema
     Parser parser = createParser("import");
 
     // -- Create Schema object and setup unmarshaller
     SchemaUnmarshaller schemaUnmarshaller = new SchemaUnmarshaller(getSchemaContext(), state);
     schemaUnmarshaller.setURIResolver(getURIResolver());
     schemaUnmarshaller.setSchema(importedSchema);
 
     // parse schema to be imported
     parseSchema(parser, schemaUnmarshaller, uri, schemaLocation, "import");
 
     // -- namespace checking
     String namespace = importedSchema.getTargetNamespace();
     if (namespace != null) {
       // -- Make sure targetNamespace is not the same as the
       // -- importing schema, see section 4.2.2 in the
       // -- XML Schema Recommendation
       if (!namespace.equals(schema.getTargetNamespace())) {
         String err =
             "The 'namespace' attribute in the <redefine> element must be the same of the targetNamespace of the global schema.\n"
                 + namespace + " is different from:" + schema.getTargetNamespace();
         error(err);
       }
     } else {
       importedSchema.setTargetNamespace(schema.getTargetNamespace());
     }
 
     // -- set the main schema in order to handle
     // -- redefinition at runtime
 
     // importedSchema.addMainSchema(schema);
 
     _importedSchema = importedSchema;
     _redefineSchema = new RedefineSchema(schema, _importedSchema);
     // -- Add schema to list of redefine schemas (if not already present)
     if (addSchema) {
       importedSchema.setSchemaLocation(schemaLocation);
       _schema.addRedefineSchema(_redefineSchema);
     }
   }
 
   /**
    * Signals the start of an element with the given name.
    *
    * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
    *        prefix).
    * @param namespace the namespace of the element. This may be null. Note: A null namespace is not
    *        the same as the default namespace unless the default namespace is also null.
    * @param atts the AttributeSet containing the attributes associated with the element.
    * @param nsDecls the namespace declarations being declared for this element. This may be null.
    **/
   public void startElement(String name, String namespace, AttributeSet atts, Namespaces nsDecls)
       throws XMLException {
 
     // -- Do delegation if necessary
     if (_unmarshaller != null) {
       try {
         _unmarshaller.startElement(name, namespace, atts, nsDecls);
         _depth++;
         return;
       } catch (RuntimeException rtx) {
         error(rtx);
       }
     }
 
     if (name.equals(SchemaNames.ANNOTATION)) {
       _unmarshaller = new AnnotationUnmarshaller(getSchemaContext(), atts);
     } else if (name.equals(SchemaNames.ATTRIBUTE_GROUP)) {
       _unmarshaller = new AttributeGroupUnmarshaller(getSchemaContext(), _schema, atts);
     } else if (name.equals(SchemaNames.COMPLEX_TYPE)) {
       _unmarshaller = new ComplexTypeUnmarshaller(getSchemaContext(), _schema, atts);
     } else if (name.equals(SchemaNames.SIMPLE_TYPE)) {
       _unmarshaller = new SimpleTypeUnmarshaller(getSchemaContext(), _schema, atts);
     } else if (name.equals(SchemaNames.GROUP)) {
       _unmarshaller = new ModelGroupUnmarshaller(getSchemaContext(), _schema, atts);
     } else {
       String err = "<" + name + "> elements cannot be used in a redefine.";
       error(err);
     }
 
     _unmarshaller.setDocumentLocator(getDocumentLocator());
 
   }
 
   /**
    * Signals to end of the element with the given name.
    *
    * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
    *        prefix).
    * @param namespace the namespace of the element.
    **/
   public void endElement(String name, String namespace) throws XMLException {
 
     // -- Do delegation if necessary
     if ((_unmarshaller != null) && (_depth > 0)) {
       _unmarshaller.endElement(name, namespace);
       --_depth;
       return;
     }
 
     // -- use internal JVM String
     name = name.intern();
 
     // -- check for name mismatches
     if ((_unmarshaller != null)) {
       if (!name.equals(_unmarshaller.elementName())) {
         String err = "error: missing end element for ";
         err += _unmarshaller.elementName();
         error(err);
       }
     } else {
       String err = "error: missing start element for " + name;
       throw new SchemaException(err);
     }
 
     // -- call unmarshaller.finish() to perform any necessary cleanup
     _unmarshaller.finish();
 
     if (name.equals(SchemaNames.ANNOTATION)) {
       _redefineSchema.addAnnotation((Annotation) _unmarshaller.getObject());
     } else if (name.equals(SchemaNames.ATTRIBUTE_GROUP)) {
       endElementForAttributeGroup();
     } else if (name.equals(SchemaNames.COMPLEX_TYPE)) {
       endElementForComplexType();
     } else if (name.equals(SchemaNames.SIMPLE_TYPE)) {
       endElementForSimpleType();
     } else if (name.equals(SchemaNames.GROUP)) {
       endElementForGroup();
     } else {
       String err =
           "In a <redefine>, only complexTypes|simpleTypes|groups or attributeGroups can be redefined.";
       error(err);
     }
 
     _unmarshaller = null;
   }
 
   private void endElementForGroup() throws XMLException, SchemaException {
     addErrorIfNoSchemaLocationDefinedUponRedefine();
 
     ModelGroup group = (((ModelGroupUnmarshaller) _unmarshaller).getGroup());
 
     String structureName = group.getName();
     addErrorIfRedefinedTypeDoesNotHaveAName(structureName, "group");
 
     // 1-- the group must exist in the imported schema
     Group original = _importedSchema.getModelGroup(structureName);
     if (original == null) {
       String err =
           "When redefining a group, the group must be present in the imported XML schema.\n"
               + "Group: " + structureName + " is not defined in XML Schema:"
               + _importedSchema.getSchemaLocation();
       error(err);
     }
 
     // -- code needs to be added to check the Particle Valid (Restriction) constraint
     // --TBD
 
     group.setRedefined();
     _redefineSchema.addGroup(group);
   }
 
   private void endElementForSimpleType() throws XMLException, SchemaException {
     addErrorIfNoSchemaLocationDefinedUponRedefine();
 
     SimpleType simpleType = ((SimpleTypeUnmarshaller) _unmarshaller).getSimpleType();
     
     String structureName = simpleType.getName();
     addErrorIfRedefinedTypeDoesNotHaveAName(structureName, "simpleType");
 
     // 1-- the simpleType must exist in the imported schema
     SimpleType original =
         _importedSchema.getSimpleType(structureName, _schema.getTargetNamespace());
     if (original == null) {
       String err =
           "When redefining a simpleType, the simpleType must be present in the imported XML schema.\n"
               + "SimpleType: " + structureName + " is not defined in XML Schema:"
               + _importedSchema.getSchemaLocation();
       error(err);
     }
 
     // 2-- the base type must be itself
     XMLType baseType = simpleType.getBaseType();
     // --just check the names since a top level complexType can only be defined once.
     if (!baseType.getName().equals(structureName)) {
       String err =
           "When redefining a simpleType, the simpleType must use itself as the base type definition.\n"
               + "SimpleType: " + structureName + " uses:" + baseType.getName()
               + " as its base type.";
       error(err);
     }
 
     simpleType.setRedefined();
     _redefineSchema.addSimpleType(simpleType);
     getResolver().addResolvable(simpleType.getReferenceId(), simpleType);
   }
 
   private void endElementForComplexType() throws XMLException, SchemaException {
     addErrorIfNoSchemaLocationDefinedUponRedefine();
     ComplexType complexType = ((ComplexTypeUnmarshaller) _unmarshaller).getComplexType();
     
     // -- Checks that the complexType exists in the imported schema
     String structureName = complexType.getName();
     addErrorIfRedefinedTypeDoesNotHaveAName(structureName, "complexType");
 
     // 1-- the complexType must exist in the imported schema
     ComplexType original = _importedSchema.getComplexType(structureName);
     if (original == null) {
       String err =
           "When redefining a complexType, the complexType must be present in the imported XML schema.\n"
               + "ComplexType: " + structureName + " is not defined in XML Schema:"
               + _importedSchema.getSchemaLocation();
       error(err);
     }
 
     // 2-- the base type must be itself
     XMLType baseType = complexType.getBaseType();
     // --just check the names since a top level complexType can only be defined once.
     if (baseType == null || !baseType.getName().equals(structureName)) {
       String err =
           "When redefining a complexType, the complexType must use itself as the base type definition.\n"
               + "ComplexType: " + structureName + " uses:" + baseType + " as its base type.";
       error(err);
     }
 
     complexType.setRedefined();
     _redefineSchema.addComplexType(complexType);
     getResolver().addResolvable(complexType.getReferenceId(), complexType);
   }
 
   private void endElementForAttributeGroup() throws XMLException, SchemaException {
     addErrorIfNoSchemaLocationDefinedUponRedefine();
 
     AttributeGroupDecl group =
         (AttributeGroupDecl) (((AttributeGroupUnmarshaller) _unmarshaller).getAttributeGroup());
 
     String structureName = group.getName();
     addErrorIfRedefinedTypeDoesNotHaveAName(structureName, "attribute group");
 
     // 1-- the attributeGroup must exist in the imported schema
     AttributeGroup original = _importedSchema.getAttributeGroup(structureName);
     if (original == null) {
       String err =
           "When redefining an AttributeGroup, the AttributeGroup must be present in the imported XML schema.\n"
               + "AttributeGroup: " + structureName + " is not defined in XML Schema:"
               + _importedSchema.getSchemaLocation();
       error(err);
     }
 
     // -- TODO: add code to check the Derivation Valid (Restriction, Complex) constraint.
     group.setRedefined();
     _redefineSchema.addAttributeGroup(group);
   }
 
   public void characters(char[] ch, int start, int length) throws XMLException {
     // -- Do delagation if necessary
     if (_unmarshaller != null) {
       _unmarshaller.characters(ch, start, length);
     }
   }
 
   /**
    * Checks that the redefined schema has a 'schemaLocation' attribute set.
    * @throws XMLException
    */
   private void addErrorIfNoSchemaLocationDefinedUponRedefine() throws XMLException {
     if (_redefineSchema.getSchemaLocation() == "") {
       String err =
           "In a <redefine>, only annotations can be defined when no -schemaLocation- is specified.";
       error(err);
     }
   }
   
   /**
    * Checks that the given type exists in the imported schema; if not, add an error
    * @param structureName Name of the structure to check
    * @param typeName Name of enclosing type
    * @throws XMLException 
    */
   private void addErrorIfRedefinedTypeDoesNotHaveAName(String structureName, String typeName) throws XMLException {
     // -- Checks that the given type exists in the imported schema
     if (structureName == null) {
       String err = "When redefining a " + typeName + ", the " + typeName + " must have a name.\n";
       error(err);
     }
   }
 
   /**
    * Sets the name of the element that this UnknownUnmarshaller handles
    **/
   public String elementName() {
     return SchemaNames.REDEFINE;
   }
 
   /**
    * Returns the Object created by this ComponentReader
    * 
    * @return the Object created by this ComponentReader
    **/
   public Object getObject() {
     return _redefineSchema;
   }
 
 }