<?php

// ----------------------------------------------------------------------------------
// Class: Resource
// ----------------------------------------------------------------------------------

/**
 * An RDF resource. 
 * Every RDF resource must have a URIref.  
 * URIrefs are treated as logical constants, i.e. as names which denote something 
 * (the things are called 'resources', but no assumptions are made about the nature of resources.) 
 * Many RDF resources are pieces of vocabulary. They typically have a namespace
 * and a local name. In this case, a URI is composed as a
 * concatenation of the namespace and the local name.
 * 
 * History:
 * 09-30-2002                : Fixed bug in getNamespace() and getLocalName().
 * 09-10-2002                : First version of this class.
 *
 * @version  V0.1
 * @author Chris Bizer <hide@address.com>
 *
 * @package model
 * @todo nothing
 * @access	public
 *
 */ 
 class Resource extends Node {

 	/**
	* URIref to the resource
	* @var		string
	* @access	private
	*/	
    var $uri;
   
  
   /**
    * Constructor
	* Takes an URI or a namespace/localname combination
    *
    * @param	string	$namespace_or_uri
 	* @param	string	$localName
	* @access	public
    */
    function Resource($namespace_or_uri , $localName = NULL) {
		if ($localName == NULL) {
			$this->uri = $namespace_or_uri;
	  	} else {
			$this->uri = $namespace_or_uri . $localName;
  	    }
	}

 
  /**
   * Returns the URI of the resource.
   * @return string
   * @access	public  
   */
  function getURI() {
  			return $this->uri;
   }

	/**
	 * Returns the label of the resource, which is the URI of the resource.
     * @access	public  
	 * @return string 
	 */
    function getLabel() {
    	return $this->getURI();
    }
	   	
  /**
   * Returns the namespace of the resource. May return null.
   * @access	public  
   * @return string
   */
  function getNamespace() {
    return RDFUtil::guessNamespace($this->uri);
  }

  /**
   * Returns the local name of the resource. 
   * @access	public  
   * @return string
   */
    function getLocalName() {
	    return RDFUtil::guessName($this->uri);
  	}
  
  /**
   * Checks if the resource equals another resource.
   * Two resources are equal, if they have the same URI
   *
   * @access	public 
   * @param		object	resource $that
   * @return	boolean 
   */  
   function equals ($that) {
	
	    if ($this == $that) {
	      return true;
	    }
	    if (($that == NULL) or !(is_a($that, "Resource"))) {
	      return false;
	    }
	    	
		if ($this->getURI() == $that->getURI()) {
	      return true;
	    }
	
	    return false;
	}
  
    /**
   * Dumps resource.
   *
   * @access	public 
   * @return	string 
   */  
  function toString() {
	$dump = "Resource(\"" . $this->uri ."\")";
    return $dump;
  }
  
} // end: Resource 






?>