/**
* A class for displaying various tree-like structures.
*
- * Extend the Walker class to use it, see examples at the below. Child classes
+ * Extend the Walker class to use it, see examples below. Child classes
* do not need to implement all of the abstract methods in the class. The child
- * only needs to implement the methods that are needed. Also, the methods are
- * not strictly abstract in that the parameter definition needs to be followed.
- * The child classes can have additional parameters.
+ * only needs to implement the methods that are needed.
*
- * @package WordPress
* @since 2.1.0
+ *
+ * @package WordPress
* @abstract
*/
class Walker {
* What the class handles.
*
* @since 2.1.0
- * @var string
* @access public
+ * @var string
*/
- var $tree_type;
+ public $tree_type;
/**
* DB fields to use.
*
* @since 2.1.0
* @var array
- * @access protected
*/
- var $db_fields;
+ public $db_fields;
/**
* Max number of pages walked by the paged walker
*
* @since 2.7.0
* @var int
- * @access protected
*/
- var $max_pages = 1;
+ public $max_pages = 1;
+
+ /**
+ * Whether the current element has children or not.
+ *
+ * To be used in start_el().
+ *
+ * @since 4.0.0
+ * @var bool
+ */
+ public $has_children;
/**
* Starts the list before the elements are added.
*
- * Additional parameters are used in child classes. The args parameter holds
- * additional values that may be used with the child class methods. This
- * method is called at the start of the output list.
+ * The $args parameter holds additional values that may be used with the child
+ * class methods. This method is called at the start of the output list.
*
* @since 2.1.0
* @abstract
*
* @param string $output Passed by reference. Used to append additional content.
+ * @param int $depth Depth of the item.
+ * @param array $args An array of additional arguments.
*/
- function start_lvl( &$output, $depth = 0, $args = array() ) {}
+ public function start_lvl( &$output, $depth = 0, $args = array() ) {}
/**
* Ends the list of after the elements are added.
*
- * Additional parameters are used in child classes. The args parameter holds
- * additional values that may be used with the child class methods. This
- * method finishes the list at the end of output of the elements.
+ * The $args parameter holds additional values that may be used with the child
+ * class methods. This method finishes the list at the end of output of the elements.
*
* @since 2.1.0
* @abstract
*
* @param string $output Passed by reference. Used to append additional content.
+ * @param int $depth Depth of the item.
+ * @param array $args An array of additional arguments.
*/
- function end_lvl( &$output, $depth = 0, $args = array() ) {}
+ public function end_lvl( &$output, $depth = 0, $args = array() ) {}
/**
* Start the element output.
*
- * Additional parameters are used in child classes. The args parameter holds
- * additional values that may be used with the child class methods. Includes
- * the element output also.
+ * The $args parameter holds additional values that may be used with the child
+ * class methods. Includes the element output also.
*
* @since 2.1.0
* @abstract
*
- * @param string $output Passed by reference. Used to append additional content.
+ * @param string $output Passed by reference. Used to append additional content.
+ * @param object $object The data object.
+ * @param int $depth Depth of the item.
+ * @param array $args An array of additional arguments.
+ * @param int $current_object_id ID of the current item.
*/
- function start_el( &$output, $object, $depth, $args, $current_object_id = 0 ) {}
+ public function start_el( &$output, $object, $depth = 0, $args = array(), $current_object_id = 0 ) {}
/**
* Ends the element output, if needed.
*
- * Additional parameters are used in child classes. The args parameter holds
- * additional values that may be used with the child class methods.
+ * The $args parameter holds additional values that may be used with the child class methods.
*
* @since 2.1.0
* @abstract
*
* @param string $output Passed by reference. Used to append additional content.
+ * @param object $object The data object.
+ * @param int $depth Depth of the item.
+ * @param array $args An array of additional arguments.
*/
- function end_el( &$output, $object, $depth = 0, $args = array() ) {}
+ public function end_el( &$output, $object, $depth = 0, $args = array() ) {}
/**
* Traverse elements to create list from elements.
* depth and no ignore elements under that depth. It is possible to set the
* max depth to include all depths, see walk() method.
*
- * This method shouldn't be called directly, use the walk() method instead.
+ * This method should not be called directly, use the walk() method instead.
*
* @since 2.5.0
*
- * @param object $element Data object
- * @param array $children_elements List of elements to continue traversing.
- * @param int $max_depth Max depth to traverse.
- * @param int $depth Depth of current element.
- * @param array $args
- * @param string $output Passed by reference. Used to append additional content.
- * @return null Null on failure with no changes to parameters.
+ * @param object $element Data object.
+ * @param array $children_elements List of elements to continue traversing.
+ * @param int $max_depth Max depth to traverse.
+ * @param int $depth Depth of current element.
+ * @param array $args An array of arguments.
+ * @param string $output Passed by reference. Used to append additional content.
*/
- function display_element( $element, &$children_elements, $max_depth, $depth=0, $args, &$output ) {
-
- if ( !$element )
+ public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
+ if ( ! $element ) {
return;
+ }
$id_field = $this->db_fields['id'];
+ $id = $element->$id_field;
//display this element
- if ( is_array( $args[0] ) )
- $args[0]['has_children'] = ! empty( $children_elements[$element->$id_field] );
- $cb_args = array_merge( array(&$output, $element, $depth), $args);
- call_user_func_array(array(&$this, 'start_el'), $cb_args);
+ $this->has_children = ! empty( $children_elements[ $id ] );
+ if ( isset( $args[0] ) && is_array( $args[0] ) ) {
+ $args[0]['has_children'] = $this->has_children; // Back-compat.
+ }
- $id = $element->$id_field;
+ $cb_args = array_merge( array(&$output, $element, $depth), $args);
+ call_user_func_array(array($this, 'start_el'), $cb_args);
// descend only when the depth is right and there are childrens for this element
if ( ($max_depth == 0 || $max_depth > $depth+1 ) && isset( $children_elements[$id]) ) {
- foreach( $children_elements[ $id ] as $child ){
+ foreach ( $children_elements[ $id ] as $child ){
if ( !isset($newlevel) ) {
$newlevel = true;
//start the child delimiter
$cb_args = array_merge( array(&$output, $depth), $args);
- call_user_func_array(array(&$this, 'start_lvl'), $cb_args);
+ call_user_func_array(array($this, 'start_lvl'), $cb_args);
}
$this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output );
}
if ( isset($newlevel) && $newlevel ){
//end the child delimiter
$cb_args = array_merge( array(&$output, $depth), $args);
- call_user_func_array(array(&$this, 'end_lvl'), $cb_args);
+ call_user_func_array(array($this, 'end_lvl'), $cb_args);
}
//end this element
$cb_args = array_merge( array(&$output, $element, $depth), $args);
- call_user_func_array(array(&$this, 'end_el'), $cb_args);
+ call_user_func_array(array($this, 'end_el'), $cb_args);
}
/**
* Display array of elements hierarchically.
*
- * It is a generic function which does not assume any existing order of
- * elements. max_depth = -1 means flatly display every element. max_depth =
- * 0 means display all levels. max_depth > 0 specifies the number of
- * display levels.
+ * Does not assume any existing order of elements.
+ *
+ * $max_depth = -1 means flatly display every element.
+ * $max_depth = 0 means display all levels.
+ * $max_depth > 0 specifies the number of display levels.
*
* @since 2.1.0
*
- * @param array $elements
- * @param int $max_depth
- * @return string
+ * @param array $elements An array of elements.
+ * @param int $max_depth The maximum hierarchical depth.
+ * @return string The hierarchical item output.
*/
- function walk( $elements, $max_depth) {
-
+ public function walk( $elements, $max_depth ) {
$args = array_slice(func_get_args(), 2);
$output = '';
- if ($max_depth < -1) //invalid parameter
- return $output;
-
- if (empty($elements)) //nothing to walk
+ //invalid parameter or nothing to walk
+ if ( $max_depth < -1 || empty( $elements ) ) {
return $output;
+ }
- $id_field = $this->db_fields['id'];
$parent_field = $this->db_fields['parent'];
// flat display
}
/*
- * need to display in hierarchical order
- * separate elements into two buckets: top level and children elements
- * children_elements is two dimensional array, eg.
- * children_elements[10][] contains all sub-elements whose parent is 10.
+ * Need to display in hierarchical order.
+ * Separate elements into two buckets: top level and children elements.
+ * Children_elements is two dimensional array, eg.
+ * Children_elements[10][] contains all sub-elements whose parent is 10.
*/
$top_level_elements = array();
$children_elements = array();
foreach ( $elements as $e) {
- if ( 0 == $e->$parent_field )
+ if ( empty( $e->$parent_field ) )
$top_level_elements[] = $e;
else
$children_elements[ $e->$parent_field ][] = $e;
}
/*
- * when none of the elements is top level
- * assume the first one must be root of the sub elements
+ * When none of the elements is top level.
+ * Assume the first one must be root of the sub elements.
*/
if ( empty($top_level_elements) ) {
$this->display_element( $e, $children_elements, $max_depth, 0, $args, $output );
/*
- * if we are displaying all levels, and remaining children_elements is not empty,
- * then we got orphans, which should be displayed regardless
+ * If we are displaying all levels, and remaining children_elements is not empty,
+ * then we got orphans, which should be displayed regardless.
*/
if ( ( $max_depth == 0 ) && count( $children_elements ) > 0 ) {
$empty_array = array();
foreach ( $children_elements as $orphans )
- foreach( $orphans as $op )
+ foreach ( $orphans as $op )
$this->display_element( $op, $empty_array, 1, 0, $args, $output );
}
* and number of elements per page, this function first determines all top level root elements
* belonging to that page, then lists them and all of their children in hierarchical order.
*
- * @package WordPress
- * @since 2.7
- * @param int $max_depth = 0 means display all levels; $max_depth > 0 specifies the number of display levels.
- * @param int $page_num the specific page number, beginning with 1.
- * @return XHTML of the specified page of elements
- */
- function paged_walk( $elements, $max_depth, $page_num, $per_page ) {
-
- /* sanity check */
- if ( empty($elements) || $max_depth < -1 )
+ * $max_depth = 0 means display all levels.
+ * $max_depth > 0 specifies the number of display levels.
+ *
+ * @since 2.7.0
+ *
+ * @param array $elements
+ * @param int $max_depth The maximum hierarchical depth.
+ * @param int $page_num The specific page number, beginning with 1.
+ * @param int $per_page
+ * @return string XHTML of the specified page of elements
+ */
+ public function paged_walk( $elements, $max_depth, $page_num, $per_page ) {
+ if ( empty( $elements ) || $max_depth < -1 ) {
return '';
+ }
$args = array_slice( func_get_args(), 4 );
$output = '';
- $id_field = $this->db_fields['id'];
$parent_field = $this->db_fields['parent'];
$count = -1;
}
/*
- * separate elements into two buckets: top level and children elements
- * children_elements is two dimensional array, eg.
- * children_elements[10][] contains all sub-elements whose parent is 10.
+ * Separate elements into two buckets: top level and children elements.
+ * Children_elements is two dimensional array, e.g.
+ * $children_elements[10][] contains all sub-elements whose parent is 10.
*/
$top_level_elements = array();
$children_elements = array();
foreach ( $top_level_elements as $e ) {
$count++;
- //for the last page, need to unset earlier children in order to keep track of orphans
+ // For the last page, need to unset earlier children in order to keep track of orphans.
if ( $end >= $total_top && $count < $start )
$this->unset_children( $e, $children_elements );
if ( $end >= $total_top && count( $children_elements ) > 0 ) {
$empty_array = array();
foreach ( $children_elements as $orphans )
- foreach( $orphans as $op )
+ foreach ( $orphans as $op )
$this->display_element( $op, $empty_array, 1, 0, $args, $output );
}
return $output;
}
- function get_number_of_root_elements( $elements ){
-
+ /**
+ * Calculates the total number of root elements.
+ *
+ * @since 2.7.0
+ * @access public
+ *
+ * @param array $elements Elements to list.
+ * @return int Number of root elements.
+ */
+ public function get_number_of_root_elements( $elements ){
$num = 0;
$parent_field = $this->db_fields['parent'];
return $num;
}
- // unset all the children for a given top level element
- function unset_children( $e, &$children_elements ){
-
- if ( !$e || !$children_elements )
+ /**
+ * Unset all the children for a given top level element.
+ *
+ * @param object $e
+ * @param array $children_elements
+ */
+ public function unset_children( $e, &$children_elements ){
+ if ( ! $e || ! $children_elements ) {
return;
+ }
$id_field = $this->db_fields['id'];
$id = $e->$id_field;
foreach ( (array) $children_elements[$id] as $child )
$this->unset_children( $child, $children_elements );
- if ( isset($children_elements[$id]) )
- unset( $children_elements[$id] );
-
+ unset( $children_elements[ $id ] );
}
-}
+
+} // Walker