/OData Producer for PHP/library/ODataProducer/UriProcessor/QueryProcessor/SkipTokenParser/InternalSkipTokenInfo.php

<?php

/**

 * Type which holds information about processed skiptoken value, this type

 * also provide method to search the given result set for the skiptoken

 * and to build skiptoken from an entry object. 

 * 

 * PHP version 5.3

 * 

 * @category  ODataProducer

 * @package   ODataProducer_UriProcessor_QueryProcessor_SkipTokenParser

 * @author    Anu T Chandy <odataphpproducer_alias@microsoft.com>

 * @copyright 2011 Microsoft Corp. (http://www.microsoft.com)

 * @license   New BSD license, (http://www.opensource.org/licenses/bsd-license.php)

 * @version   SVN: 1.0

 * @link      http://odataphpproducer.codeplex.com

 * 

 */

namespace ODataProducer\UriProcessor\QueryProcessor\SkipTokenParser;

use ODataProducer\Providers\Metadata\Type\Guid;

use ODataProducer\Providers\Metadata\Type\Null1;

use ODataProducer\Providers\Metadata\Type\DateTime;

use ODataProducer\Providers\Metadata\Type\String;

use ODataProducer\Providers\Metadata\ResourceType;

use ODataProducer\UriProcessor\QueryProcessor\OrderByParser\InternalOrderByInfo;

use ODataProducer\Common\Messages;

use ODataProducer\Common\ODataException;

/**

 * Type to hold information about processed skiptoken value.

 *

 * @category  ODataProducer

 * @package   ODataProducer_UriProcessor_QueryProcessor_SkipTokenParser

 * @author    Anu T Chandy <odataphpproducer_alias@microsoft.com>

 * @copyright 2011 Microsoft Corp. (http://www.microsoft.com)

 * @license   New BSD license, (http://www.opensource.org/licenses/bsd-license.php)

 * @version   Release: 1.0

 * @link      http://odataphpproducer.codeplex.com

 */

class InternalSkipTokenInfo

{

    /**

     * Reference to an instance of InternalOrderByInfo which holds 

     * sorter function(s) generated from orderby clause.

     * 

     * @var InternalOrderByInfo

     */

    private $_internalOrderByInfo;



    /**

     * Holds collection of values in the skiptoken corrosponds to the orderby

     * path segments.

     * 

     * @var array(int (array(string, IType))

     */

    private $_orderByValuesInSkipToken;



    /**

     * Holds reference to the type of the resource pointed by the request uri.

     * 

     * @var ResourceType

     */

    private $_resourceType;



    /**

     * Reference to the object holding parsed skiptoken value, this information

     * can be used by the IDSQP implementor for custom paging.

     * 

     * @var SkipTokenInfo

     */

    private $_skipTokenInfo;



    /**

     * Object which is used as a key for searching the sorted result, this object

     * will be an instance of type described by the resource type pointed by the 

     * request uri.

     * 

     * @var mixed

     */

    private $_keyObject;

    



    /**

     * Creates a new instance of InternalSkipTokenInfo

     * 

     * @param InternalOrderByInfo           &$internalOrderByInfo     Reference to an instance of InternalOrderByInfo which holds

     *                                                                sorter function(s) generated from orderby clause.

     * @param array(int(array(string,IType) $orderByValuesInSkipToken Collection of values in the skiptoken corrosponds to the 

     *                                                                orderby path segments.

     * @param ResourceType                  &$resourceType            Reference to the type of the resource pointed by the request uri.

     */

    public function __construct(InternalOrderByInfo &$internalOrderByInfo, 

        $orderByValuesInSkipToken, ResourceType &$resourceType

    ) {

        $this->_internalOrderByInfo = $internalOrderByInfo;        

        $this->_orderByValuesInSkipToken = $orderByValuesInSkipToken;

        $this->_resourceType = $resourceType;

        $this->_skipTokenInfo = null;

        $this->_keyObject = null;

    }



    /**

     * Gets reference to the SkipTokenInfo object holding result of 

     * skiptoken parsing, which used by the IDSQP implementor for 

     * custom paging.

     * 

     * @return SkipTokenInfo

     */

    public function getSkipTokenInfo()

    {

        if (is_null($this->_skipTokenInfo)) {

            $orderbyInfo = $this->_internalOrderByInfo->getOrderByInfo();

            $this->_skipTokenInfo = new SkipTokenInfo(

                $orderbyInfo, 

                $this->_orderByValuesInSkipToken

            );

        }



        return $this->_skipTokenInfo;

    }



    /**

     * Search the sorted array of result set for key object created from the

     * skip token key values and returns index of first entry in the next

     * page.

     * 

     * @param array(mixed) &$searchArray The sorted array to search.

     * 

     * @return int  (1) If the array is empty then return -1, 

     *              (2) If the key object found then return index of first record 

     *                  in the next page, 

     *              (3) If partial matching found (means found matching for first 

     *                  m keys where m < n, where n is total number of positional 

     *                  keys, then return the index of the object which has most 

     *                  matching.

     * 

     * @throws InvalidArgumentException

     */

    public function getIndexOfFirstEntryInTheNextPage(&$searchArray)

    {

        if (!is_array($searchArray)) {

            throw new \InvalidArgumentException(

                Messages::internalSkipTokenInfoBinarySearchRequireArray(

                    'searchArray'

                )

            );

        }



        if (empty($searchArray)) {

            return -1;

        }



        $comparer 

            = $this->_internalOrderByInfo->getSorterFunction()->getReference();

        //Gets the key object initialized from skiptoken

        $keyObject = $this->getKeyObject();

        $low = 0;

        $searcArraySize = count($searchArray) - 1;

        $mid = 0;

        $high = $searcArraySize;

        do {

            $matchLevel = 0;

            $mid = $low + round(($high - $low)/2);

            $result = $comparer($keyObject, $searchArray[$mid]);

            if ($result > 0) {

                $low = $mid + 1;

            } else if ($result < 0) {

                $high = $mid - 1;

            } else {

                //Now we found record the matches with skiptoken value, 

                //so first record of next page will at $mid + 1

                if ($mid == $searcArraySize) {

                    //Check skiptoken points to last record, in this 

                    //case no more records available for next page

                    return -1;

                }



                return $mid + 1;

            }

        } while ($low <= $high);

 

        if ($mid >= $searcArraySize) {

            //If key object does not match with last object, then 

            //no more page

            return -1;

        } else if ($mid <= 0) {

            //If key object is less than first object, then paged 

            //result start from 0

            return 0;

        }

        

        //return index of the most matching object

        return $mid;        

    }



    /**

     * Gets the key object for searching, if the object is not initialized, 

     * then do it from skiptoken positional values.

     * 

     * @return mixed

     * 

     * @throws ODataException If reflection exception occurs while accessing 

     *                        or setting property.

     */

    public function getKeyObject()

    {

        if (is_null($this->_keyObject)) {

            $this->_keyObject = $this->_internalOrderByInfo->getDummyObject();

            $i = 0;

            foreach ($this->_internalOrderByInfo->getOrderByPathSegments() 

                as $orderByPathSegment) {

                $index = 0;

                $currentObject = $this->_keyObject;

                $subPathSegments = $orderByPathSegment->getSubPathSegments();

                $subPathCount = count($subPathSegments);

                foreach ($subPathSegments as &$subPathSegment) {

                    $isLastSegment = ($index == $subPathCount - 1);

                    $dummyProperty = null;

                    try {

                        // if currentObject = null means, previous iteration did a 

                        // ReflectionProperty::getValue where ReflectionProperty 

                        // represents a complex/navigation, but its null, which means

                        // the property is not set in the dummy object by OrderByParser, 

                        // an unexpected state.

                        if (!$isLastSegment) {

                            $dummyProperty = new \ReflectionProperty(

                                $currentObject, 

                                $subPathSegment->getName()

                            );

                            $currentObject 

                                = $dummyProperty->getValue($currentObject);

                        } else {

                            $dummyProperty = new \ReflectionProperty(

                                $currentObject, 

                                $subPathSegment->getName()

                            );

                            if ($this->_orderByValuesInSkipToken[$i][1] instanceof Null1) {

                                $dummyProperty->setValue($currentObject, null);

                            } else {

                                // The Lexer's Token::Text value will be always 

                                // string, convert the string to 

                                // required type i.e. int, float, double etc..

                                $value 

                                    = $this->_orderByValuesInSkipToken[$i][1]->convert(

                                        $this->_orderByValuesInSkipToken[$i][0]

                                    );

                                $dummyProperty->setValue($currentObject, $value);

                            }

                        }

                    } catch (\ReflectionException $reflectionException) {

                        throw ODataException::createInternalServerError(

                            Messages::internalSkipTokenInfoFailedToAccessOrInitializeProperty(

                                $subPathSegment->getName()

                            )

                        );

                    }



                    $index++;

                }



                $i++;

            }

        }



        return $this->_keyObject;

    }

    

    /**

     * Build nextpage link from the given object which will be the last object

     * in the page.

     * 

     * @param mixed $lastObject Entity instance to build next page link from.

     * 

     * @return string

     * 

     * @throws ODataException If reflection exception occurs while accessing 

     *                        property.

     */

    public function buildNextPageLink($lastObject)

    {

        $nextPageLink = null;

        foreach ($this->_internalOrderByInfo->getOrderByPathSegments() 

        as $orderByPathSegment) {

            $index = 0;

            $currentObject = $lastObject;

            $subPathSegments = $orderByPathSegment->getSubPathSegments();

            $subPathCount = count($subPathSegments);

            foreach ($subPathSegments as &$subPathSegment) {

                $isLastSegment = ($index == $subPathCount - 1);

                try {

                    $dummyProperty = new \ReflectionProperty(

                        $currentObject, 

                        $subPathSegment->getName()

                    );

                    $currentObject = $dummyProperty->getValue($currentObject);

                    if (is_null($currentObject)) {

                            $nextPageLink .= 'null, ';

                            break;

                    } else if ($isLastSegment) {

                        $type = $subPathSegment->getInstanceType();

                        $value = $type->convertToOData($currentObject);

                        $nextPageLink .= $value . ', ';

                    }                    

                } catch (\ReflectionException $reflectionException) {

                    throw ODataException::createInternalServerError(

                        Messages::internalSkipTokenInfoFailedToAccessOrInitializeProperty(

                            $subPathSegment->getName()

                        )

                    );

                }



                $index++;

            }

        }



        return rtrim($nextPageLink, ", ");

    }

}

?>