<?php

/*

 * 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.

 *

 * This software consists of voluntary contributions made by many individuals

 * and is licensed under the LGPL. For more information, see

 * <http://www.doctrine-project.org>.

 */

namespace Doctrine\ORM\Id;

use Serializable, Doctrine\ORM\EntityManager;

/**

 * Represents an ID generator that uses a database sequence.

 *

 * @since 2.0

 * @author Roman Borschel <roman@code-factory.org>

 */

class SequenceGenerator extends AbstractIdGenerator implements Serializable

{

    private $_allocationSize;

    private $_sequenceName;

    private $_nextValue = 0;

    private $_maxValue = null;

    /**

     * Initializes a new sequence generator.

     *

     * @param Doctrine\ORM\EntityManager $em The EntityManager to use.

     * @param string $sequenceName The name of the sequence.

     * @param integer $allocationSize The allocation size of the sequence.

     */

    public function __construct($sequenceName, $allocationSize)

    {

        $this->_sequenceName = $sequenceName;

        $this->_allocationSize = $allocationSize;

    }

    /**

     * Generates an ID for the given entity.

     *

     * @param object $entity

     * @return integer|float The generated value.

     * @override

     */

    public function generate(EntityManager $em, $entity)

    {

        if ($this->_maxValue === null || $this->_nextValue == $this->_maxValue) {

            // Allocate new values

            $conn = $em->getConnection();

            $sql = $conn->getDatabasePlatform()->getSequenceNextValSQL($this->_sequenceName);

            $this->_nextValue = $conn->fetchColumn($sql);

            $this->_maxValue = $this->_nextValue + $this->_allocationSize;

        }

        return $this->_nextValue++;

    }

    /**

     * Gets the maximum value of the currently allocated bag of values.

     *

     * @return integer|float

     */

    public function getCurrentMaxValue()

    {

        return $this->_maxValue;

    }

    /**

     * Gets the next value that will be returned by generate().

     *

     * @return integer|float

     */

    public function getNextValue()

    {

        return $this->_nextValue;

    }

    public function serialize()

    {

        return serialize(array(

            'allocationSize' => $this->_allocationSize,

            'sequenceName' => $this->_sequenceName

        ));

    }

    public function unserialize($serialized)

    {

        $array = unserialize($serialized);

        $this->_sequenceName = $array['sequenceName'];

        $this->_allocationSize = $array['allocationSize'];

    }

}