// ContentId.h

#ifndef ContentId_H
#define ContentId_H

// David Adams
// June 2002
//
// Content identifier.
//
// XML format is
//
// ContentId
//   name = MyClass
//   key = mykey
//
// The key is optional.

#include <string>
#include <iosfwd>
#include "dataset_util/Text.h"

class XmlElement;

class ContentId {

public:  // typedefs

  typedef unsigned int Index;
  typedef unsigned int size_type;

  // Unique class index.
  unsigned int m_idx;

  // Persistent class name.
  std::string m_name;

  // String key.
  // Distinguishes EDO's of the same type (class index).
  std::string _key;

public:  // static functions

  // Register a class.
  static ContentId private_register_id(int idx, const char* name);

public:  // static functions

  // Return the XML name for this class.
  static const char* xml_name() { return "ContentId"; }

  // XML DTD.
  static const Text& dtd();

public:  // functions

  // Initialize the class.
  // This should be called before any content ID's are accessed
  // during C++ initialization. It will be called automatically
  // before any calls from main().
  // Return is the number of calls that have been made.
  static int initialize();

  // Register a class.
  // These are temporary values and must be < 1000.
  // Permanent values are larger.
  // A valid identifier is returned if successful.
  // Existing indices and names must match.
  static ContentId register_id(int idx, const char* name);

  // Return the number of content ID's.
  static size_type size();

  // Display the table of content ID's.
  static void display(std::ostream& strm);

public:  // functions

  // Default constructor.
  ContentId();

  // Constructor from index.
  // Index must already be registered.
  // Indices 101-106 are registered for test purposes.
  explicit ContentId(Index idx, std::string key ="");

  // Constructor from class name.
  // Name must already be registered.
  explicit ContentId(std::string name, std::string key ="");

  // Construct from an XMlElement.
  explicit ContentId(const XmlElement& pele);

  // Validity.
  bool is_valid() const;

  // Index.
  Index index() const;

  // Name.
  std::string name() const;
  const char* cname() const;

  // Key.
  std::string key() const;
  const char* ckey() const;

  // Convert to an XmlElement.
  const XmlElement* xml() const;

};

// Ordering.
bool operator<(const ContentId& lhs, const ContentId& rhs);

// Equality.
bool operator==(const ContentId& lhs, const ContentId& rhs);

// Output stream.
std::ostream& operator<<(std::ostream& lhs, const ContentId& rhs);

#endif