An XML parser and editor with shades of a Design Pattern

/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 */

/*
 * $Id: DOM_NodeList.hpp 176026 2004-09-08 13:57:07Z peiyongz $
 */

#ifndef DOM_NodeList_HEADER_GUARD_
#define DOM_NodeList_HEADER_GUARD_

#include <xercesc/util/XercesDefs.hpp>
#include "DOM_Node.hpp"

XERCES_CPP_NAMESPACE_BEGIN


class NodeListImpl;

/**
 * The <code>NodeList</code> interface provides the abstraction of an ordered
 * collection of nodes.  NodeLists are created by DOM_Document::getElementsByTagName(),
 * DOM_Node::getChildNodes(),
 *
 * <p>The items in the <code>NodeList</code> are accessible via an integral
 * index, starting from 0.
 *
 * NodeLists are "live", in that any changes to the document tree are immediately
 * reflected in any NodeLists that may have been created for that tree.
 */

class  DEPRECATED_DOM_EXPORT DOM_NodeList {
private:
    NodeListImpl *fImpl;

public:
    /** @name Constructors and assignment operator */
    //@{
    /**
      * Default constructor for DOM_NodeList.  The resulting object does not
      * refer to an actual NodeList; it will compare == to 0, and is similar
      * to a null object reference variable in Java.  It may subsequently be
      * assigned to refer to an actual NodeList.
      *
      */
    DOM_NodeList();

    /**
      * Copy constructor.
      *
      * @param other The object to be copied.
      */
    DOM_NodeList(const DOM_NodeList &other);

    /**
      * Assignment operator.
      *
      * @param other The object to be copied.
      */
    DOM_NodeList & operator = (const DOM_NodeList &other);

    /**
      * Assignment operator.  This overloaded variant is provided for
      *   the sole purpose of setting a DOM_Node reference variable to
      *   zero.  Nulling out a reference variable in this way will decrement
      *   the reference count on the underlying Node object that the variable
      *   formerly referenced.  This effect is normally obtained when reference
      *   variable goes out of scope, but zeroing them can be useful for
      *   global instances, or for local instances that will remain in scope
      *   for an extended time,  when the storage belonging to the underlying
      *   node needs to be reclaimed.
      *
      * @param val   Only a value of 0, or null, is allowed.
      */
    DOM_NodeList & operator = (const DOM_NullPtr *val);

    //@}
    /** @name Destructor. */
    //@{
	 /**
	  * Destructor for DOM_NodeList.  The object being destroyed is the reference
      * object, not the underlying NodeList node itself.
	  *
      * <p>Like most other DOM types in this implementation, memory management
      * of Node Lists is automatic.  Instances of DOM_NodeList function
      * as references to an underlying heap based implementation object,
      * and should never be explicitly new-ed or deleted in application code, but
      * should appear only as local variables or function parameters.
	  */
    ~DOM_NodeList();
    //@}

    /** @name Comparison operators. */
    //@{

    /**
      *  Equality operator.
      *  Compares whether two node list
      *  variables refer to the same underlying node list.  It does
      *  not compare the contents of the node lists themselves.
      *
      *  @param other The value to be compared
      *  @return Returns true if node list refers to same underlying node list
      */
    bool operator == (const DOM_NodeList &other) const;

    /**
     *  Use this comparison operator to test whether a Node List reference
     *  is null.
     *
     *  @param nullPtr The value to be compared, which must be 0 or null.
     *  @return Returns true if node list reference is null
     */
    bool operator == (const DOM_NullPtr *nullPtr) const;

     /**
      *  Inequality operator.
      *  Compares whether two node list
      *  variables refer to the same underlying node list.  It does
      *  not compare the contents of the node lists themselves.
      *
      *  @param other The value to be compared
      *  @return Returns true if node list refers to a different underlying node list
      */
    bool operator != (const DOM_NodeList &other) const;

    /**
     *  Use this comparison operator to test whether a Node List reference
     *  is not null.
     *
     *  @param nullPtr The value to be compared, which must be 0 or null.
     *  @return Returns true if node list reference is not null
     */
    bool operator != (const DOM_NullPtr *nullPtr) const;
    //@}


    /** @name Get functions. */
    //@{
    /**
     * Returns the <code>index</code>th item in the collection.
     *
     * If <code>index</code> is greater than or equal to the number of nodes in
     * the list, this returns <code>null</code>.
     *
     * @param index Index into the collection.
     * @return The node at the <code>index</code>th position in the
     *   <code>NodeList</code>, or <code>null</code> if that is not a valid
     *   index.
     */
    DOM_Node  item(unsigned int index) const;

    /**
     * Returns the number of nodes in the list.
     *
     * The range of valid child node indices is 0 to <code>length-1</code> inclusive.
     */
    unsigned int getLength() const;
    //@}

protected:
    DOM_NodeList(NodeListImpl *impl);

    friend class DOM_Document;
    friend class DOM_Element;
    friend class DOM_Node;
    friend class DOM_Entity;

};

XERCES_CPP_NAMESPACE_END

#endif