package javax.xml.stream.events;

import javax.xml.namespace.QName;
import javax.xml.namespace.NamespaceContext;

import java.util.Map;
import java.util.Iterator;

/**
 * The StartElement interface provides access to information about
 * start elements.  A StartElement is reported for each Start Tag 
 * in the document.  
 *
 * @version 1.0
 * @author Copyright (c) 2003 by BEA Systems. All Rights Reserved.
 * @since 1.6
 */
public interface StartElement extends XMLEvent {

  /**
   * Get the name of this event
   * @return the qualified name of this event
   */
  public QName getName();

  /**
   * Returns an Iterator of non-namespace declared attributes declared on 
   * this START_ELEMENT,
   * returns an empty iterator if there are no attributes.  The
   * iterator must contain only implementations of the javax.xml.stream.Attribute
   * interface.   Attributes are fundamentally unordered and may not be reported
   * in any order.
   *
   * @return a readonly Iterator over Attribute interfaces, or an
   * empty iterator
   */
  public Iterator getAttributes();

  /**
   * Returns an Iterator of namespaces declared on this element.
   * This Iterator does not contain previously declared namespaces
   * unless they appear on the current START_ELEMENT.
   * Therefore this list may contain redeclared namespaces and duplicate namespace
   * declarations. Use the getNamespaceContext() method to get the
   * current context of namespace declarations.
   *  
   * <p>The iterator must contain only implementations of the 
   * javax.xml.stream.Namespace interface.
   * 
   * <p>A Namespace isA Attribute.  One
   * can iterate over a list of namespaces as a list of attributes.  
   * However this method returns only the list of namespaces 
   * declared on this START_ELEMENT and does not
   * include the attributes declared on this START_ELEMENT.
   *
   * Returns an empty iterator if there are no namespaces.
   *
   * @return a readonly Iterator over Namespace interfaces, or an
   * empty iterator
   *
   */
  public Iterator getNamespaces();

  /**
   * Returns the attribute referred to by this name
   * @param name the qname of the desired name
   * @return the attribute corresponding to the name value or null
   */
  public Attribute getAttributeByName(QName name);

  /**
   * Gets a read-only namespace context. If no context is 
   * available this method will return an empty namespace context.
   * The NamespaceContext contains information about all namespaces
   * in scope for this StartElement.
   *
   * @return the current namespace context
   */
  public NamespaceContext getNamespaceContext();

  /**
   * Gets the value that the prefix is bound to in the
   * context of this element.  Returns null if 
   * the prefix is not bound in this context
   * @param prefix the prefix to lookup
   * @return the uri bound to the prefix or null
   */
  public String getNamespaceURI(String prefix);
}