UnionUnmarshaller

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package org.exolab.castor.xml.schema.reader;

// -- imported classes and packages
import java.util.StringTokenizer;

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.Schema;
import org.exolab.castor.xml.schema.SchemaContext;
import org.exolab.castor.xml.schema.SchemaNames;
import org.exolab.castor.xml.schema.SimpleType;
import org.exolab.castor.xml.schema.Union;

/**
 * A class for Unmarshalling XML Schema Union types
 *
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
 **/
public class UnionUnmarshaller extends ComponentReader {

  // --------------------/
  // - Member Variables -/
  // --------------------/

  /**
   * The current ComponentReader
   **/
  private ComponentReader _unmarshaller;

  /**
   * The current branch depth
   **/
  private int _depth = 0;

  /**
   * The Union we are unmarshalling
   **/
  private Union _union = null;

  /**
   * The parent Schema for the Union
   **/
  private Schema _schema = null;

  private boolean _foundAnnotation = false;
  private boolean _foundSimpleType = false;

  // ----------------/
  // - Constructors -/
  // ----------------/

  /**
   * Creates a new IdentityConstraintUnmarshaller
   *
   * @param schemaContext the {@link SchemaContext} to get some configuration settings from
   * @param atts the AttributeList
   **/
  public UnionUnmarshaller(final SchemaContext schemaContext, final Schema schema,
      final AttributeSet atts) throws XMLException {
    super(schemaContext);

    if (schema == null) {
      String err = "'schema' must not be null.";
      throw new IllegalStateException(err);
    }
    _schema = schema;

    _union = new Union(_schema);
    _union.setId(atts.getValue(SchemaNames.ID_ATTR));

    String memberTypes = atts.getValue(SchemaNames.MEMBER_TYPES_ATTR);
    processMemberTypes(memberTypes);

  } // -- UnionUnmarshaller

  // -----------/
  // - Methods -/
  // -----------/

  /**
   * Returns the name of the element that this ComponentReader handles
   *
   * @return the name of the element that this ComponentReader handles
   **/
  public String elementName() {
    return SchemaNames.UNION;
  } // -- elementName

  /**
   * Returns the Object created by this ComponentReader
   *
   * @return the Object created by this ComponentReader
   **/
  public Object getObject() {
    return _union;
  } // -- getObject

  public void finish() throws XMLException {
    // -- do nothing
  } // -- finish

  /**
   * 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 delagation if necessary
    if (_unmarshaller != null) {
      _unmarshaller.startElement(name, namespace, atts, nsDecls);
      ++_depth;
      return;
    }

    if (SchemaNames.ANNOTATION.equals(name)) {

      if (_foundAnnotation)
        error("Only one (1) annotation may appear as a child of '" + elementName() + "'.");

      if (_foundSimpleType)
        error("An annotation may only appear as the first child of '" + elementName() + "'.");

      _foundAnnotation = true;
      _unmarshaller = new AnnotationUnmarshaller(getSchemaContext(), atts);
    } else if (SchemaNames.SIMPLE_TYPE.equals(name)) {
      _foundSimpleType = true;
      _unmarshaller = new SimpleTypeUnmarshaller(getSchemaContext(), _schema, atts);
    } else
      illegalElement(name);

  } // -- startElement

  /**
   * 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 delagation if necessary
    if ((_unmarshaller != null) && (_depth > 0)) {
      _unmarshaller.endElement(name, namespace);
      --_depth;
      return;
    }

    // -- have unmarshaller perform any necessary clean up
    _unmarshaller.finish();

    if (SchemaNames.ANNOTATION.equals(name)) {
      _union.setLocalAnnotation((Annotation) _unmarshaller.getObject());
    } else if (SchemaNames.SIMPLE_TYPE.equals(name)) {

      SimpleType simpleType = (SimpleType) _unmarshaller.getObject();

      // -- make sure type is not another Union
      if (simpleType instanceof Union) {
        String err = "A 'union' may only contain SimpleTypes of " + "the atomic or list variety.";
        error(err);
      }
      // -- make sure type is atomic or list
      // XXXX to be added later

      _union.addMemberType(simpleType);
    }


    _unmarshaller = null;
  } // -- endElement

  public void characters(char[] ch, int start, int length) throws XMLException {
    // -- Do delagation if necessary
    if (_unmarshaller != null) {
      _unmarshaller.characters(ch, start, length);
    }
  } // -- characters


  /**
   * Processes the given string into the referenced simpleTypes for the Union being unmarshalled.
   *
   * @param memberTypes the memberTypes list.
   **/
  private void processMemberTypes(String memberTypes) {
    if ((memberTypes == null) || (memberTypes.length() == 0))
      return;

    StringTokenizer st = new StringTokenizer(memberTypes);
    while (st.hasMoreTokens()) {
      String typeName = st.nextToken();
      SimpleType simpleType = _schema.getSimpleType(typeName);
      if (simpleType != null) {
        _union.addMemberType(simpleType);
      } else {
        _union.addMemberType(typeName);
      }

    }
  } // -- processMemberTypes

} // -- UnionUnmarshaller