class PagerDefault

Query extender for pager queries.

This is the "default" pager mechanism. It creates a paged query with a fixed number of entries per page.

Hierarchy

Expanded class hierarchy of PagerDefault

11 string references to 'PagerDefault'
blog_page_last in drupal/modules/blog/blog.pages.inc
Menu callback; displays a Drupal page containing recent blog entries of all users.
blog_page_user in drupal/modules/blog/blog.pages.inc
Menu callback; displays a Drupal page containing recent blog entries of a given user.
comment_get_thread in drupal/modules/comment/comment.module
Retrieve comments for a thread.
DatabaseSelectPagerDefaultTestCase::testHavingPagerQuery in drupal/modules/simpletest/tests/database_test.test
Confirm that a paging query with a having expression returns valid results.
DatabaseSelectPagerDefaultTestCase::testInnerPagerQuery in drupal/modules/simpletest/tests/database_test.test
Confirm that a pager query with inner pager query returns valid results.

... See full list

File

drupal/includes/pager.inc, line 15
Functions to aid in presenting database results as a set of pages.

View source
class PagerDefault extends SelectQueryExtender {

  /**
   * The highest element we've autogenerated so far.
   *
   * @var int
   */
  static $maxElement = 0;

  /**
   * The number of elements per page to allow.
   *
   * @var int
   */
  protected $limit = 10;

  /**
   * The unique ID of this pager on this page.
   *
   * @var int
   */
  protected $element = NULL;

  /**
   * The count query that will be used for this pager.
   *
   * @var SelectQueryInterface
   */
  protected $customCountQuery = FALSE;
  public function __construct(SelectQueryInterface $query, DatabaseConnection $connection) {
    parent::__construct($query, $connection);

    // Add pager tag. Do this here to ensure that it is always added before
    // preExecute() is called.
    $this
      ->addTag('pager');
  }

  /**
   * Override the execute method.
   *
   * Before we run the query, we need to add pager-based range() instructions
   * to it.
   */
  public function execute() {

    // Add convenience tag to mark that this is an extended query. We have to
    // do this in the constructor to ensure that it is set before preExecute()
    // gets called.
    if (!$this
      ->preExecute($this)) {
      return NULL;
    }

    // A NULL limit is the "kill switch" for pager queries.
    if (empty($this->limit)) {
      return;
    }
    $this
      ->ensureElement();
    $total_items = $this
      ->getCountQuery()
      ->execute()
      ->fetchField();
    $current_page = pager_default_initialize($total_items, $this->limit, $this->element);
    $this
      ->range($current_page * $this->limit, $this->limit);

    // Now that we've added our pager-based range instructions, run the query normally.
    return $this->query
      ->execute();
  }

  /**
   * Ensure that there is an element associated with this query.
   * If an element was not specified previously, then the value of the
   * $maxElement counter is taken, after which the counter is incremented.
   *
   * After running this method, access $this->element to get the element for this
   * query.
   */
  protected function ensureElement() {
    if (!isset($this->element)) {
      $this->element = self::$maxElement++;
    }
  }

  /**
   * Specify the count query object to use for this pager.
   *
   * You will rarely need to specify a count query directly.  If not specified,
   * one is generated off of the pager query itself.
   *
   * @param SelectQueryInterface $query
   *   The count query object.  It must return a single row with a single column,
   *   which is the total number of records.
   */
  public function setCountQuery(SelectQueryInterface $query) {
    $this->customCountQuery = $query;
  }

  /**
   * Retrieve the count query for this pager.
   *
   * The count query may be specified manually or, by default, taken from the
   * query we are extending.
   *
   * @return SelectQueryInterface
   *   A count query object.
   */
  public function getCountQuery() {
    if ($this->customCountQuery) {
      return $this->customCountQuery;
    }
    else {
      return $this->query
        ->countQuery();
    }
  }

  /**
   * Specify the maximum number of elements per page for this query.
   *
   * The default if not specified is 10 items per page.
   *
   * @param $limit
   *   An integer specifying the number of elements per page.  If passed a false
   *   value (FALSE, 0, NULL), the pager is disabled.
   */
  public function limit($limit = 10) {
    $this->limit = $limit;
    return $this;
  }

  /**
   * Specify the element ID for this pager query.
   *
   * The element is used to differentiate different pager queries on the same
   * page so that they may be operated independently.  If you do not specify an
   * element, every pager query on the page will get a unique element.  If for
   * whatever reason you want to explicitly define an element for a given query,
   * you may do so here.
   *
   * Setting the element here also increments the static $maxElement counter,
   * which is used for determining the $element when there's none specified.
   *
   * Note that no collision detection is done when setting an element ID
   * explicitly, so it is possible for two pagers to end up using the same ID
   * if both are set explicitly.
   *
   * @param $element
   */
  public function element($element) {
    $this->element = $element;
    if ($element >= self::$maxElement) {
      self::$maxElement = $element + 1;
    }
    return $this;
  }

}

Members

Name Modifierssort descending Type Description Overrides
SelectQueryExtender::isNull function Sets a condition that the specified field be NULL. Overrides QueryConditionInterface::isNull
SelectQueryExtender::isNotNull function Sets a condition that the specified field be NOT NULL. Overrides QueryConditionInterface::isNotNull
PagerDefault::ensureElement protected function Ensure that there is an element associated with this query. If an element was not specified previously, then the value of the $maxElement counter is taken, after which the counter is incremented.
PagerDefault::$limit protected property The number of elements per page to allow.
PagerDefault::$element protected property The unique ID of this pager on this page.
PagerDefault::$customCountQuery protected property The count query that will be used for this pager.
SelectQueryExtender::$query protected property The SelectQuery object we are extending/decorating.
SelectQueryExtender::$connection protected property The connection object on which to run this query.
SelectQueryExtender::$uniqueIdentifier protected property A unique identifier for this query object.
SelectQueryExtender::$placeholder protected property The placeholder counter.
PagerDefault::__construct public function Overrides SelectQueryExtender::__construct
PagerDefault::execute public function Override the execute method. Overrides SelectQueryExtender::execute
PagerDefault::setCountQuery public function Specify the count query object to use for this pager.
PagerDefault::getCountQuery public function Retrieve the count query for this pager.
PagerDefault::limit public function Specify the maximum number of elements per page for this query.
PagerDefault::element public function Specify the element ID for this pager query.
SelectQueryExtender::uniqueIdentifier public function Implements QueryPlaceholderInterface::uniqueIdentifier(). Overrides QueryPlaceholderInterface::uniqueIdentifier
SelectQueryExtender::nextPlaceholder public function Implements QueryPlaceholderInterface::nextPlaceholder(). Overrides QueryPlaceholderInterface::nextPlaceholder
SelectQueryExtender::addTag public function Adds a tag to a query. Overrides QueryAlterableInterface::addTag
SelectQueryExtender::hasTag public function Determines if a given query has a given tag. Overrides QueryAlterableInterface::hasTag
SelectQueryExtender::hasAllTags public function Determines if a given query has all specified tags. Overrides QueryAlterableInterface::hasAllTags
SelectQueryExtender::hasAnyTag public function Determines if a given query has any specified tag. Overrides QueryAlterableInterface::hasAnyTag
SelectQueryExtender::addMetaData public function Adds additional metadata to the query. Overrides QueryAlterableInterface::addMetaData
SelectQueryExtender::getMetaData public function Retrieves a given piece of metadata. Overrides QueryAlterableInterface::getMetaData
SelectQueryExtender::condition public function Helper function: builds the most common conditional clauses. Overrides QueryConditionInterface::condition
SelectQueryExtender::conditions public function Gets a complete list of all conditions in this conditional clause. Overrides QueryConditionInterface::conditions
SelectQueryExtender::arguments public function Gets a complete list of all values to insert into the prepared statement. Overrides QueryConditionInterface::arguments
SelectQueryExtender::where public function Adds an arbitrary WHERE clause to the query. Overrides QueryConditionInterface::where
SelectQueryExtender::compile public function Compiles the saved conditions for later retrieval. Overrides QueryConditionInterface::compile
SelectQueryExtender::compiled public function Check whether a condition has been previously compiled. Overrides QueryConditionInterface::compiled
SelectQueryExtender::havingCondition public function Helper function to build most common HAVING conditional clauses. Overrides SelectQueryInterface::havingCondition
SelectQueryExtender::havingConditions public function
SelectQueryExtender::havingArguments public function
SelectQueryExtender::having public function
SelectQueryExtender::havingCompile public function
SelectQueryExtender::extend public function Enhance this object by wrapping it in an extender object. Overrides QueryExtendableInterface::extend
SelectQueryExtender::getFields public function Returns a reference to the fields array for this query. Overrides SelectQueryInterface::getFields
SelectQueryExtender::getExpressions public function Returns a reference to the expressions array for this query. Overrides SelectQueryInterface::getExpressions
SelectQueryExtender::getOrderBy public function Returns a reference to the order by array for this query. Overrides SelectQueryInterface::getOrderBy
SelectQueryExtender::getGroupBy public function Returns a reference to the group-by array for this query. Overrides SelectQueryInterface::getGroupBy
SelectQueryExtender::getTables public function Returns a reference to the tables array for this query. Overrides SelectQueryInterface::getTables
SelectQueryExtender::getUnion public function Returns a reference to the union queries for this query. This include queries for UNION, UNION ALL, and UNION DISTINCT. Overrides SelectQueryInterface::getUnion
SelectQueryExtender::getArguments public function Compiles and returns an associative array of the arguments for this prepared statement. Overrides SelectQueryInterface::getArguments
SelectQueryExtender::isPrepared public function Indicates if preExecute() has already been called on that object. Overrides SelectQueryInterface::isPrepared
SelectQueryExtender::preExecute public function Generic preparation and validation for a SELECT query. Overrides SelectQueryInterface::preExecute
SelectQueryExtender::distinct public function Sets this query to be DISTINCT. Overrides SelectQueryInterface::distinct
SelectQueryExtender::addField public function Adds a field to the list to be SELECTed. Overrides SelectQueryInterface::addField
SelectQueryExtender::fields public function Add multiple fields from the same table to be SELECTed. Overrides SelectQueryInterface::fields
SelectQueryExtender::addExpression public function Adds an expression to the list of "fields" to be SELECTed. Overrides SelectQueryInterface::addExpression
SelectQueryExtender::join public function Default Join against another table in the database. Overrides SelectQueryInterface::join
SelectQueryExtender::innerJoin public function Inner Join against another table in the database. Overrides SelectQueryInterface::innerJoin
SelectQueryExtender::leftJoin public function Left Outer Join against another table in the database. Overrides SelectQueryInterface::leftJoin
SelectQueryExtender::rightJoin public function Right Outer Join against another table in the database. Overrides SelectQueryInterface::rightJoin
SelectQueryExtender::addJoin public function Join against another table in the database. Overrides SelectQueryInterface::addJoin
SelectQueryExtender::orderBy public function Orders the result set by a given field. Overrides SelectQueryInterface::orderBy
SelectQueryExtender::orderRandom public function Orders the result set by a random value. Overrides SelectQueryInterface::orderRandom
SelectQueryExtender::range public function Restricts a query to a given range in the result set. Overrides SelectQueryInterface::range
SelectQueryExtender::union public function Add another Select query to UNION to this one. Overrides SelectQueryInterface::union
SelectQueryExtender::groupBy public function Groups the result set by the specified field. Overrides SelectQueryInterface::groupBy
SelectQueryExtender::forUpdate public function Add FOR UPDATE to the query. Overrides SelectQueryInterface::forUpdate
SelectQueryExtender::countQuery public function Get the equivalent COUNT query of this query as a new query object. Overrides SelectQueryInterface::countQuery 1
SelectQueryExtender::exists public function Sets a condition that the specified subquery returns values. Overrides QueryConditionInterface::exists
SelectQueryExtender::notExists public function Sets a condition that the specified subquery returns no values. Overrides QueryConditionInterface::notExists
SelectQueryExtender::__toString public function
SelectQueryExtender::__clone public function Clone magic method. Overrides SelectQueryInterface::__clone
SelectQueryExtender::__call public function Magic override for undefined methods.
PagerDefault::$maxElement static property The highest element we've autogenerated so far.