<?php
/**
 * A database wrapper for distributed hash tables
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.shipsimu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
class NodeDistributedHashTableDatabaseWrapper extends BaseDatabaseWrapper implements NodeDhtWrapper, Registerable {
	/**
	 * "Cached" results for dabase for looking for unpublished entries
	 */
	private $unpublishedEntriesInstance = NULL;

	// Constants for database table names
	const DB_TABLE_NODE_DHT = 'node_dht';

	// Constants for database column names
	const DB_COLUMN_NODE_ID            = 'node_id';
	const DB_COLUMN_SESSION_ID         = 'session_id';
	const DB_COLUMN_EXTERNAL_IP        = 'external_ip';
	const DB_COLUMN_LISTEN_PORT        = 'listen_port';
	const DB_COLUMN_PRIVATE_KEY_HASH   = 'private_key_hash';
	const DB_COLUMN_NODE_MODE          = 'node_mode';
	const DB_COLUMN_ACCEPTED_OBJECTS   = 'accepted_object_types';
	const DB_COLUMN_NODE_LIST          = 'node_list';
	const DB_COLUMN_PUBLICATION_STATUS = 'publication_status';
	const DB_COLUMN_ANSWER_STATUS      = 'answer_status';
	const DB_COLUMN_ACCEPT_BOOTSTRAP   = 'accept_bootstrap';

	// Publication status'
	const PUBLICATION_STATUS_PENDING = 'PENDING';

	// Exception codes
	const EXCEPTION_NODE_ALREADY_REGISTERED = 0x800;
	const EXCEPTION_NODE_NOT_REGISTERED     = 0x801;

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Creates an instance of this database wrapper by a provided user class
	 *
	 * @return	$wrapperInstance	An instance of the created wrapper class
	 */
	public static final function createNodeDistributedHashTableDatabaseWrapper () {
		// Get a new instance
		$wrapperInstance = new NodeDistributedHashTableDatabaseWrapper();

		// Set (primary!) table name
		$wrapperInstance->setTableName(self::DB_TABLE_NODE_DHT);

		// Return the instance
		return $wrapperInstance;
	}

	/**
	 * Static getter for an array of all DHT database entries
	 *
	 * @return	$elements	All elements for the DHT dabase
	 */
	public static final function getAllElements () {
		// Create array and ...
		$elements = array(
			self::DB_COLUMN_NODE_ID,
			self::DB_COLUMN_SESSION_ID,
			self::DB_COLUMN_EXTERNAL_IP,
			self::DB_COLUMN_LISTEN_PORT,
			self::DB_COLUMN_PRIVATE_KEY_HASH,
			self::DB_COLUMN_NODE_MODE,
			self::DB_COLUMN_ACCEPTED_OBJECTS,
			self::DB_COLUMN_NODE_LIST
		);

		// ... return it
		return $elements;
	}

	/**
	 * Prepares a search instance for given node data
	 *
	 * @param	$nodeData			An array with valid node data
	 * @return	$searchInstance		An instance of a SearchCriteria class
	 */
	private function prepareSearchInstance (array $nodeData) {
		// Assert on array elements
		assert(isset($nodeData[self::DB_COLUMN_NODE_ID]));

		// Get instance
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Search for node id and limit it to one entry
		$searchInstance->addCriteria(self::DB_COLUMN_NODE_ID, $nodeData[self::DB_COLUMN_NODE_ID]);
		$searchInstance->setLimit(1);

		// Return it
		return $searchInstance;
	}

	/**
	 * Getter for result instance for unpublished entries
	 *
	 * @return	$unpublishedEntriesInstance		Result instance
	 */
	public final function getUnpublishedEntriesInstance () {
		return $this->unpublishedEntriesInstance;
	}

	/**
	 * Prepares a "local" instance of a StoreableCriteria class with all node
	 * data for insert/update queries. This data set contains data from *this*
	 * (local) node.
	 *
	 * @return	$dataSetInstance	An instance of a StoreableCriteria class
	 */
	private function prepareLocalDataSetInstance () {
		// Get node/request instances
		$nodeInstance = NodeObjectFactory::createNodeInstance();
		$requestInstance = ApplicationHelper::getSelfInstance()->getRequestInstance();

		// Get a dataset instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));

		// Set the primary key
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_NODE_ID);

		// Get ip:port combination and "explode" it
		$ipPort = $nodeInstance->getAddressPortArray();

		// Make sure both is valid
		assert(($ipPort[0] !== 'invalid') && ($ipPort[1] !== 'invalid'));

		// Get an array of all accepted object types
		$objectList = $nodeInstance->getListFromAcceptedObjectTypes();

		// Make sure this is an array
		assert(is_array($objectList));

		// Add public node data
		$dataSetInstance->addCriteria(self::DB_COLUMN_NODE_MODE       , $requestInstance->getRequestElement('mode'));
		$dataSetInstance->addCriteria(self::DB_COLUMN_EXTERNAL_IP     , $ipPort[0]);
		$dataSetInstance->addCriteria(self::DB_COLUMN_LISTEN_PORT     , $ipPort[1]);
		$dataSetInstance->addCriteria(self::DB_COLUMN_NODE_ID         , $nodeInstance->getNodeId());
		$dataSetInstance->addCriteria(self::DB_COLUMN_SESSION_ID      , $nodeInstance->getSessionId());
		$dataSetInstance->addCriteria(self::DB_COLUMN_PRIVATE_KEY_HASH, $nodeInstance->getPrivateKeyHash());
		$dataSetInstance->addCriteria(self::DB_COLUMN_ACCEPTED_OBJECTS, implode(BaseHubNode::OBJECT_LIST_SEPARATOR, $objectList));
		$dataSetInstance->addCriteria(self::DB_COLUMN_ACCEPT_BOOTSTRAP, $this->translateBooleanToYesNo($nodeInstance->isAcceptingDhtBootstrap()));

		// Return it
		return $dataSetInstance;
	}

	/**
	 * Checks whether the local (*this*) node is registered in the DHT by
	 * checking if the external ip/port is found.
	 *
	 * @return	$isRegistered	Whether *this* node is registered in the DHT
	 */
	public function isLocalNodeRegistered () {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Get a search criteria instance
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Get node instance
		$nodeInstance = NodeObjectFactory::createNodeInstance();

		// Get ip:port combination and "explode" it
		$ipPort = $nodeInstance->getAddressPortArray();

		/*
		 * Make sure both is not 'invalid' which means that the resolver
		 * didn't work.
		 */
		assert(($ipPort[0] !== 'invalid') && ($ipPort[1] !== 'invalid'));

		// Add ip:port/node id as criteria
		$searchInstance->addCriteria(self::DB_COLUMN_EXTERNAL_IP, $ipPort[0]);
		$searchInstance->addCriteria(self::DB_COLUMN_LISTEN_PORT, $ipPort[1]);
		$searchInstance->addCriteria(self::DB_COLUMN_NODE_ID    , $nodeInstance->getNodeId());
		$searchInstance->addCriteria(self::DB_COLUMN_SESSION_ID , $nodeInstance->getSessionId());
		$searchInstance->setLimit(1);

		// Query database and get a result instance back
		$resultInstance = $this->doSelectByCriteria($searchInstance);

		// Cache result of if there is an entry, valid() will tell us if an entry is there
		$isRegistered = $resultInstance->valid();

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: isRegistered=' . intval($isRegistered) . ' - EXIT!');

		// Return result
		return $isRegistered;
	}

	/**
	 * Registeres the local (*this*) node with its data in the DHT.
	 *
	 * @return	void
	 */
	public function registerLocalNode () {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Assert to make sure this method is called with no record in DB (the actual backend of the DHT)
		assert(!$this->isLocalNodeRegistered());

		// Get prepared data set instance
		$dataSetInstance = $this->prepareLocalDataSetInstance();

		// "Insert" this dataset instance completely into the database
		$this->queryInsertDataSet($dataSetInstance);

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');
	}

	/**
	 * Updates local (*this*) node's data in DHT, this is but not limited to the
	 * session id, ip number (and/or hostname) and port number.
	 *
	 * @return	void
	 */
	public function updateLocalNode () {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Assert to make sure this method is called with one record in DB (the actual backend of the DHT)
		assert($this->isLocalNodeRegistered());

		// Get node instance
		$nodeInstance = NodeObjectFactory::createNodeInstance();

		// Get search criteria
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Search for node id and limit it to one entry
		$searchInstance->addCriteria(self::DB_COLUMN_NODE_ID, $nodeInstance->getNodeId());
		$searchInstance->setLimit(1);

		// Get a prepared dataset instance
		$dataSetInstance = $this->prepareLocalDataSetInstance();

		// Set search instance
		$dataSetInstance->setSearchInstance($searchInstance);

		// Update DHT database record
		$this->queryUpdateDataSet($dataSetInstance);

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');
	}

	/**
	 * Finds a node locally by given session id
	 *
	 * @param	$sessionId	Session id to lookup
	 * @return	$nodeData	Node data array
	 */
	public function findNodeLocalBySessionId ($sessionId) {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: sessionId=' . $sessionId . ' - CALLED!');

		// Get search criteria
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Search for session id and limit it to one entry
		$searchInstance->addCriteria(self::DB_COLUMN_SESSION_ID, $sessionId);
		$searchInstance->setLimit(1);

		// Query database and get a result instance back
		$resultInstance = $this->doSelectByCriteria($searchInstance);

		// Return result instance
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: resultInstance->valid()=' . intval($resultInstance->valid()) . ' - EXIT!');
		return $resultInstance;
	}

	/**
	 * Registeres a node by given message data.
	 *
	 * @param	$messageData		An array of all message data
	 * @param	$handlerInstance	An instance of a HandleableDataSet class
	 * @return	void
	 */
	public function registerNodeByMessageData (array $messageData, HandleableDataSet $handlerInstance) {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: handlerInstance=' . $handlerInstance->__toString() . ' - CALLED!');

		// Get a data set instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));

		// Set primary key (session id)
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_SESSION_ID);

		// Add all array elements
		$handlerInstance->addArrayToDataSet($dataSetInstance, $messageData);

		// Remove 'node_list'
		$dataSetInstance->unsetCriteria(self::DB_COLUMN_NODE_LIST);

		// Run the "INSERT" query
		$this->queryInsertDataSet($dataSetInstance);

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . '] - EXIT!');
	}

	/**
	 * Updates an existing entry in node list
	 *
	 * @param	$messageData		An array of all message data
	 * @param	$handlerInstance	An instance of a HandleableDataSet class
	 * @param	$searchInstance		An instance of LocalSearchCriteria class
	 * @return	void
	 */
	public function updateNodeByMessageData (array $messageData, HandleableDataSet $handlerInstance, LocalSearchCriteria $searchInstance) {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Get a data set instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));

		// Add search instance
		$dataSetInstance->setSearchInstance($searchInstance);

		// Set primary key (session id)
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_SESSION_ID);

		// Add all array elements
		$handlerInstance->addArrayToDataSet($dataSetInstance, $messageData);

		// Remove 'node_list'
		$dataSetInstance->unsetCriteria(self::DB_COLUMN_NODE_LIST);

		// Run the "UPDATE" query
		$this->queryUpdateDataSet($dataSetInstance);

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');
	}

	/**
	 * Determines whether the given node data is already inserted in the DHT
	 *
	 * @param	$nodeData		An array with valid node data
	 * @return	$isRegistered	Whether the given node data is already inserted
	 */
	public function isNodeRegistered (array $nodeData) {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Assert on array elements
		assert(isset($nodeData[self::DB_COLUMN_NODE_ID]));

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: node-id=' . $nodeData[self::DB_COLUMN_NODE_ID]);

		// Get search criteria
		$searchInstance = $this->prepareSearchInstance($nodeData);

		// Query database and get a result instance back
		$resultInstance = $this->doSelectByCriteria(
			// Search instance
			$searchInstance,
			// Only look for these array elements ("keys")
			array(
				self::DB_COLUMN_NODE_ID     => TRUE,
				self::DB_COLUMN_EXTERNAL_IP => TRUE,
				self::DB_COLUMN_LISTEN_PORT => TRUE,
			)
		);

		// Check if there is an entry
		$isRegistered = $resultInstance->valid();

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: isRegistered=' . intval($isRegistered) . ' - EXIT!');

		// Return registration status
		return $isRegistered;
	}

	/**
	 * Registers a node with given data in the DHT. If the node is already
	 * registered this method shall throw an exception.
	 *
	 * @param	$nodeData	An array with valid node data
	 * @return	void
	 * @throws	NodeAlreadyRegisteredException	If the node is already registered
	 */
	public function registerNode (array $nodeData) {
		// Assert on array elements
		assert(isset($nodeData[self::DB_COLUMN_NODE_ID]));

		// Is the node registered?
		if ($this->isNodeRegistered($nodeData)) {
			// Throw an exception
			throw new NodeAlreadyRegisteredException(array($this, $nodeData), self::EXCEPTION_NODE_ALREADY_REGISTERED);
		} // END - if

		// @TODO Unimplemented part
		$this->partialStub('nodeData=' . print_r($nodeData, TRUE));
	}

	/**
	 * Updates a node's entry in the DHT with given data. This will enrich or
	 * just update already exsiting data. If the node is not found this method
	 * shall throw an exception.
	 *
	 * @param	$nodeData	An array with valid node data
	 * @return	void
	 * @throws	NodeDataMissingException	If the node's data is missing
	 */
	public function updateNode (array $nodeData) {
		// Assert on array elements
		assert(isset($nodeData[self::DB_COLUMN_NODE_ID]));

		// Debug message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: Updating DHT entry for node-id=' . $nodeData[self::DB_COLUMN_NODE_ID] . ' ...');

		// Is the node registered?
		if (!$this->isNodeRegistered($nodeData)) {
			// No, then throw an exception
			throw new NodeDataMissingException(array($this, $nodeData), self::EXCEPTION_NODE_NOT_REGISTERED);
		} // END - if

		// Get a search instance
		$searchInstance = $this->prepareSearchInstance($nodeData);

		// Get a data set instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));

		// Add search instance
		$dataSetInstance->setSearchInstance($searchInstance);

		// Set primary key (session id)
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_SESSION_ID);

		// Get node instance
		$nodeInstance = NodeObjectFactory::createNodeInstance();

		// Debug message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: nodeData=' . print_r($nodeData, TRUE));

		// Add all array elements
		$nodeInstance->addArrayToDataSet($dataSetInstance, $nodeData);

		// Remove 'node_list'
		$dataSetInstance->unsetCriteria(self::DB_COLUMN_NODE_LIST);

		// Run the "UPDATE" query
		$this->queryUpdateDataSet($dataSetInstance);
	}

	/**
	 * Checks whether there are unpublished entries
	 *
	 * @return	$hasUnpublished		Whether there are unpublished entries
	 * @todo	Add minimum/maximum age limitations
	 */
	public function hasUnpublishedEntries () {
		// Get search instance
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Add exclusion key which is the publish status
		$searchInstance->addExcludeCriteria(NodeDistributedHashTableDatabaseWrapper::DB_COLUMN_PUBLICATION_STATUS, NodeDistributedHashTableDatabaseWrapper::PUBLICATION_STATUS_PENDING);

		// Remember search instance
		$this->setSearchInstance($searchInstance);

		// Run the query
		$this->unpublishedEntriesInstance = $this->doSelectByCriteria($searchInstance);

		// Check pending entries
		$hasUnpublished = $this->unpublishedEntriesInstance->valid();

		// Return it
		return $hasUnpublished;
	}

	/**
	 * Initializes publication of DHT entries. This does only prepare
	 * publication. The next step is to pickup such prepared entries and publish
	 * them by uploading to other (recently appeared) DHT members.
	 *
	 * @return	void
	 * @todo	Add timestamp to dataset instance
	 */
	public function initEntryPublication () {
		/*
		 * Make sure that hasUnpublishedEntries() has been called first by
		 * asserting on the "cached" object instance. This "caching" saves some
		 * needless queries as this method shall be called immediately after
		 * hasUnpublishedEntries() returns TRUE.
		 */
		assert($this->unpublishedEntriesInstance instanceof SearchableResult);

		// Result is still okay?
		assert($this->unpublishedEntriesInstance->valid());

		// Remove 'publication_status'
		$this->getSearchInstance()->unsetCriteria(self::DB_COLUMN_PUBLICATION_STATUS);

		// Make sure all entries are marked as pending, first get a dataset instance.
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));

		// Add search instance
		$dataSetInstance->setSearchInstance($this->getSearchInstance());

		// Set primary key (node id)
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_NODE_ID);

		// Add criteria (that should be set)
		$dataSetInstance->addCriteria(self::DB_COLUMN_PUBLICATION_STATUS, self::PUBLICATION_STATUS_PENDING);

		// Run the "UPDATE" query
		$this->queryUpdateDataSet($dataSetInstance);
	}

	/**
	 * Removes non-public data from given array.
	 *
	 * @param	$data	An array with possible non-public data that needs to be removed.
	 * @return	$data	A cleaned up array with only public data.
	 */
	public function removeNonPublicDataFromArray(array $data) {
		// Currently call only inner method
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: Calling parent::removeNonPublicDataFromArray(data) ...');
		$data = parent::removeNonPublicDataFromArray($data);
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: data[]=' . gettype($data));

		// Return cleaned data
		return $data;
	}

	/**
	 * Find recipients for given package data and exclude the sender
	 *
	 * @param	$packageData	An array of valid package data
	 * @return	$recipients		An indexed array with DHT recipients
	 */
	public function getResultFromExcludedSender (array $packageData) {
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: CALLED!');

		// Assert on required array field
		assert(isset($packageData[NetworkPackage::PACKAGE_DATA_SENDER]));

		// Get max recipients
		$maxRecipients = $this->getConfigInstance()->getConfigEntry('max_dht_recipients');

		// First creata a search instance
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Then exclude 'sender' field as the sender is the current (*this*) node
		$searchInstance->addExcludeCriteria(NodeDistributedHashTableDatabaseWrapper::DB_COLUMN_SESSION_ID, $packageData[NetworkPackage::PACKAGE_DATA_SENDER]);

		// Set limit to maximum DHT recipients
		$searchInstance->setLimit($maxRecipients);

		// Get a result instance back from DHT database wrapper.
		$resultInstance = $this->doSelectByCriteria($searchInstance);

		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: EXIT!');

		// Return result instance
		return $resultInstance;
	}

	/**
	 * Find recopients by given key/value pair. First look for the key and if it
	 * matches, compare the value.
	 *
	 * @param	$key			Key to look for
	 * @param	$value			Value to compare if key matches
	 * @return	$recipients		An indexed array with DHT recipients
	 */
	public function getResultFromKeyValue ($key, $value) {
		// Get max recipients
		$maxRecipients = $this->getConfigInstance()->getConfigEntry('max_dht_recipients');

		// First creata a search instance
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Find the key/value pair
		$searchInstance->addCriteria($key, $value);

		// Get a result instance back from DHT database wrapper.
		$resultInstance = $this->doSelectByCriteria($searchInstance);

		// Return result instance
		return $resultInstance;
	}

	/**
	 * Enable DHT bootstrap request acceptance for local node
	 *
	 * @return	void
	 */
	public function enableAcceptDhtBootstrap () {
		// Debug message
		/* DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-WRAPPER[' . __METHOD__ . ':' . __LINE__ . ']: Enabling DHT bootstrap requests ...');

		// Is the node already registered?
		if ($this->isLocalNodeRegistered()) {
			// Just update our record
			$this->updateLocalNode();
		} else {
			// Register it
			$this->registerLocalNode();
		}
	}
}

// [EOF]
?>