--- /dev/null
+<?php
+
+/**
+ * EasyRdf
+ *
+ * LICENSE
+ *
+ * Copyright (c) 2009-2013 Nicholas J Humfrey. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author 'Nicholas J Humfrey" may be used to endorse or
+ * promote products derived from this software without specific prior
+ * written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package EasyRdf
+ * @copyright Copyright (c) 2009-2013 Nicholas J Humfrey
+ * @license http://www.opensource.org/licenses/bsd-license.php
+ */
+
+/**
+ * Class that represents an RDF Literal of datatype xsd:date
+ *
+ * @package EasyRdf
+ * @link http://www.w3.org/TR/xmlschema-2/#date
+ * @copyright Copyright (c) 2009-2013 Nicholas J Humfrey
+ * @license http://www.opensource.org/licenses/bsd-license.php
+ */
+class EasyRdf_Literal_Date extends EasyRdf_Literal
+{
+ /** Constructor for creating a new date literal
+ *
+ * If the value is a DateTime object, then it will be converted to the xsd:date format.
+ * If no value is given or is is null, then the current date is used.
+ *
+ * @see DateTime
+ *
+ * @param mixed $value The value of the literal
+ * @param string $lang Should be null (literals with a datatype can't have a language)
+ * @param string $datatype Optional datatype (default 'xsd:date')
+ * @return object EasyRdf_Literal_Date
+ */
+ public function __construct($value = null, $lang = null, $datatype = null)
+ {
+ // If $value is null, use today's date
+ if (is_null($value)) {
+ $value = new DateTime('today');
+ }
+
+ // Convert DateTime object into string
+ if ($value instanceof DateTime) {
+ $value = $value->format('Y-m-d');
+ }
+
+ parent::__construct($value, null, $datatype);
+ }
+
+ /** Parses a string using DateTime and creates a new literal
+ *
+ * Example:
+ * $date = EasyRdf_Literal_Date::parse('1 January 2011');
+ *
+ * @see DateTime
+ * @param string $value The date to parse
+ * @return object EasyRdf_Literal_Date
+ */
+ public static function parse($value)
+ {
+ $value = new DateTime($value);
+ return new EasyRdf_Literal_Date($value);
+ }
+
+ /** Returns the date as a PHP DateTime object
+ *
+ * @see DateTime::format
+ * @return string
+ */
+ public function getValue()
+ {
+ return new DateTime($this->value);
+ }
+
+ /** Returns date formatted according to given format
+ *
+ * @see DateTime::format
+ * @param string $format
+ * @return string
+ */
+ public function format($format)
+ {
+ return $this->getValue()->format($format);
+ }
+
+ /** A full integer representation of the year, 4 digits
+ *
+ * @return integer
+ */
+ public function year()
+ {
+ return (int)$this->format('Y');
+ }
+
+ /** Integer representation of the month
+ *
+ * @return integer
+ */
+ public function month()
+ {
+ return (int)$this->format('m');
+ }
+
+ /** Integer representation of the day of the month
+ *
+ * @return integer
+ */
+ public function day()
+ {
+ return (int)$this->format('d');
+ }
+}