one/src/scheduler/include/ObjectXML.h

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/* Copyright 2002-2010, OpenNebula Project Leads (OpenNebula.org)             */
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/* Licensed under the Apache License, Version 2.0 (the "License"); you may    */
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#ifndef OBJECT_XML_H_
#define OBJECT_XML_H_

#include <string>
#include <vector>

#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>

using namespace std;

/**
 *  This class represents a generic Object supported by a xml document.
 *  The class provides basic methods to query attributes, and get xml nodes
 */
class ObjectXML
{
public:

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

    ObjectXML():xml(0),ctx(0){};

    /**
     *  Constructs an object using a XML document
     */
    ObjectXML(const string &xml_doc);

    /**
     *  Constructs an object using a XML Node. The node is copied to the new
     *  object
     */
    ObjectXML(const xmlNodePtr node);

    virtual ~ObjectXML();

    /**
     *  Access Object elements using Xpath
     *    @param xpath_expr the Xpath of the element
     *    @return a vector with the elements
     */
    vector<string> operator[] (const char * xpath_expr);

    /**
     *  Get xml nodes by Xpath
     *    @param xpath_expr the Xpath for the elements
     *    @param content nodes for the given Xpath expression. The nodes are
     *    returned as pointers to the object nodes.
     *    @return the number of nodes found
     */
    int get_nodes (const char * xpath_expr, vector<xmlNodePtr>& content);

    /**
     *   Updates the object representation with a new XML document. Previous
     *   XML resources are freed
     *   @param xml_doc the new xml document
     */
    int update(const string &xml_doc);

private:
    /**
     *  XML representation of the Object
     */
    xmlDocPtr   xml;

    /**
     *  XPath Context to access Object elements
     */
    xmlXPathContextPtr ctx;

    /**
     *  Parse a XML documents and initializes XPath contexts
     */
    void xml_parse(const string &xml_doc);
};

#endif /*OBJECT_XML_H_*/