/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://jaxp.dev.java.net/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * https://jaxp.dev.java.net/CDDLv1.0.html
 * If applicable add the following below this CDDL HEADER
 * with the fields enclosed by brackets "[]" replaced with
 * your own identifying information: Portions Copyright
 * [year] [name of copyright owner]
 */

/*
 * $Id: XMLEntityReader.java,v 1.3 2005/11/03 17:02:21 jeffsuttor Exp $
 * @(#)NamespaceContext.java	1.14 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
 */

package javax.xml.namespace;

import java.util.Iterator;

/**
 * <p>Interface for read only XML Namespace context processing.</p>
 *
 * <p>An XML Namespace has the properties:</p>
 * <ul>
 *   <li>Namespace URI:
 *       Namespace name expressed as a URI to which the prefix is bound</li>
 *   <li>prefix: syntactically, this is the part of the attribute name
 *       following the <code>XMLConstants.XMLNS_ATTRIBUTE</code>
 *       ("xmlns") in the Namespace declaration</li>
 * </ul>
 * <p>example:
 * <code><element xmlns:prefix="http://Namespace-name-URI"></code></p>
 *
 * <p>All <code>get*(*)</code> methods operate in the current scope
 * for Namespace URI and prefix resolution.</p>
 *
 * <p>Note that a Namespace URI can be bound to
 * <strong>multiple</strong> prefixes in the current scope.  This can
 * occur when multiple <code>XMLConstants.XMLNS_ATTRIBUTE</code>
 * ("xmlns") Namespace declarations occur in the same Start-Tag and
 * refer to the same Namespace URI. e.g.<br />
 * <pre>
 * <element xmlns:prefix1="http://Namespace-name-URI"
 *          xmlns:prefix2="http://Namespace-name-URI">
 * </pre>
 * This can also occur when the same Namespace URI is used in multiple
 * <code>XMLConstants.XMLNS_ATTRIBUTE</code> ("xmlns") Namespace
 * declarations in the logical parent element hierarchy.  e.g.<br />
 * <pre>
 * <parent xmlns:prefix1="http://Namespace-name-URI">
 *   <child xmlns:prefix2="http://Namespace-name-URI">
 *     ...
 *   </child>
 * </parent>
 * </pre></p>
 *
 * <p>A prefix can only be bound to a <strong>single</strong>
 * Namespace URI in the current scope.</p>
 *
 * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 * @version $Revision: 1.2 $, $Date: 2005/06/10 03:50:28 $
 * @see javax.xml.XMLConstants
 *   javax.xml.XMLConstants for declarations of common XML values
 * @see <a href="http://www.w3.org/TR/xmlschema-2/#QName">
 *   XML Schema Part2: Datatypes</a>
 * @see <a href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">
 *   Namespaces in XML</a>
 * @see <a href="http://www.w3.org/XML/xml-names-19990114-errata">
 *   Namespaces in XML Errata</a>
 * @since 1.5
 */

public interface NamespaceContext {

    /**
     * <p>Get Namespace URI bound to a prefix in the current scope.</p>
     *
     * <p>When requesting a Namespace URI by prefix, the following
     * table describes the returned Namespace URI value for all
     * possible prefix values:</p>
     *
     * <table border="2" rules="all" cellpadding="4">
     *   <thead>
     *     <tr>
     *       <td align="center" colspan="2">
     *         <code>getNamespaceURI(prefix)</code>
     *         return value for specified prefixes
     *       </td>