content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package mf.org.apache.xerces.xni;
  
  import java.util.Enumeration;
  
  /**
   * Represents an interface to query namespace information.
   * <p/>
   * The prefix and namespace must be identical references for equal strings, thus
   * each string should be internalized (@see String.intern())
   * or added to the <code>SymbolTable</code>
   *
   * @author Andy Clark, IBM
   * @version $Id: NamespaceContext.java 447247 2006-09-18 05:23:52Z mrglavas $
   * @see <a href="../../../../../xerces2/org/apache/xerces/util/SymbolTable.html">
   * org.apache.xerces.util.SymbolTable</a>
   */
  public interface NamespaceContext {
  
      //
      // Constants
      //
  
      /**
       * The XML Namespace ("http://www.w3.org/XML/1998/namespace"). This is
       * the Namespace URI that is automatically mapped to the "xml" prefix.
       */
      String XML_URI = "http://www.w3.org/XML/1998/namespace".intern();
  
      /**
       * XML Information Set REC
       * all namespace attributes (including those named xmlns,
       * whose [prefix] property has no value) have a namespace URI of http://www.w3.org/2000/xmlns/
       */
      String XMLNS_URI = "http://www.w3.org/2000/xmlns/".intern();
  
      //
      // NamespaceContext methods
      //
  
      /**
       * Start a new Namespace context.
       * <p/>
       * A new context should be pushed at the beginning
       * of each XML element: the new context will automatically inherit
       * the declarations of its parent context, but it will also keep
       * track of which declarations were made within this context.
       * <p/>
       *
       * @see #popContext
       */
      void pushContext();
  
      /**
       * Revert to the previous Namespace context.
       * <p/>
       * The context should be popped at the end of each
       * XML element.  After popping the context, all Namespace prefix
       * mappings that were previously in force are restored.
       * <p/>
       * Users must not attempt to declare additional Namespace
       * prefixes after popping a context, unless you push another
       * context first.
       *
       * @see #pushContext
       */
      void popContext();
  
      /**
       * Declare a Namespace prefix.
       * <p/>
       * This method declares a prefix in the current Namespace
       * context; the prefix will remain in force until this context
       * is popped, unless it is shadowed in a descendant context.
       * <p/>
       * Note that to declare a default Namespace, use the empty string.
       * The prefixes "xml" and "xmlns" can't be rebound.
       * <p/>
       * Note that you must <em>not</em> declare a prefix after
       * you've pushed and popped another Namespace.
       *
       * @param prefix The prefix to declare, or null for the empty
       *               string.
       * @param uri    The Namespace URI to associate with the prefix.
       * @return true if the prefix was legal, false otherwise
       * @see #getURI
       * @see #getDeclaredPrefixAt
       */
      boolean declarePrefix(String prefix, String uri);
  
  
      /**
       * Look up a prefix and get the currently-mapped Namespace URI.
       * <p/>
       * This method looks up the prefix in the current context. If no mapping
       * is found, this methods will continue lookup in the parent context(s).
       * Use the empty string ("") for the default Namespace.
       *
       * @param prefix The prefix to look up.
       * @return The associated Namespace URI, or null if the prefix
       * is undeclared in this context.
       */
      String getURI(String prefix);
  
      /**
       * Look up a namespace URI and get one of the mapped prefix.
       * <p/>
       * This method looks up the namespace URI in the current context.
       * If more than one prefix is currently mapped to the same URI,
       * this method will make an arbitrary selection
       * If no mapping is found, this methods will continue lookup in the
       * parent context(s).
       *
       * @param uri The namespace URI to look up.
       * @return One of the associated prefixes, or null if the uri
       * does not map to any prefix.
       * @see #getPrefix
       */
      String getPrefix(String uri);
  
      /**
       * Return a count of locally declared prefixes, including
       * the default prefix if bound.
       */
      int getDeclaredPrefixCount();
  
      /**
       * Returns the prefix at the specified index in the current context.
       */
      String getDeclaredPrefixAt(int index);
  
      /**
       * Return an enumeration of all prefixes whose declarations are active
       * in the current context. This includes declarations from parent contexts
       * that have not been overridden.
       *
       * @return Enumeration
       */
      Enumeration getAllPrefixes();
  
      /**
       * Reset this Namespace support object for reuse.
       * <p/>
       * <p>It is necessary to invoke this method before reusing the
       * Namespace support object for a new session.</p>
       * <p/>
       * <p>Note that implementations of this method need to ensure that
       * the declaration of the prefixes "xmlns" and "xml" are available.</p>
       */
      void reset();
  
  
  } // interface NamespaceContext
  