core_availability\tree_node Class Reference

Node (base class) used to construct a tree of availability conditions. More...

Inheritance diagram for core_availability\tree_node:

Public Member Functions
	check_available ($not, core_availability\info $info, $grabthelot, $userid)
	Determines whether this particular item is currently available according to the availability criteria. More...
	filter_user_list (array $users, $not, core_availability\info $info, capability_checker $checker)
	Tests this condition against a user list. More...
	get_user_list_sql ($not, core_availability\info $info, $onlyactive)
	Obtains SQL that returns a list of enrolled users that has been filtered by the conditions applied in the availability API, similar to calling get_enrolled_users and then filter_user_list. More...
	include_after_restore ($restoreid, $courseid, base_logger $logger, $name, base_task $task)
	Checks whether this node should be included after restore or not. More...
	is_applied_to_user_lists ()
	Checks whether this condition applies to user lists. More...
	is_available_for_all ($not=false)
	Checks whether this condition is actually going to be available for all users under normal circumstances. More...
	save ()
	Saves tree data back to a structure object. More...
	update_after_restore ($restoreid, $courseid, base_logger $logger, $name)
	Updates this node after restore, returning true if anything changed. More...
	update_dependency_id ($table, $oldid, $newid)
	Updates this node if it contains any references (dependencies) to the given table and id. More...

Static Protected Member Functions
static	unique_sql_parameter (array &$params, $value)
	Utility function for generating SQL parameters (because we can't use ? parameters because get_enrolled_sql has infected us with horrible named parameters). More...

Static Protected Attributes
static int	$uniquesqlparametercounter = 1
	Counter to be used in tree_node::unique_sql_parameter().

Detailed Description

Node (base class) used to construct a tree of availability conditions.

Copyright

2014 The Open University

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Member Function Documentation

check_available()

core_availability\tree_node::check_available (   $not, core_availability\info  $info,   $grabthelot,   $userid  )

abstract

Determines whether this particular item is currently available according to the availability criteria.

• This does not include the 'visible' setting (i.e. this might return true even if visible is false); visible is handled independently.
• This does not take account of the viewhiddenactivities capability. That should apply later.

The $not option is potentially confusing. This option always indicates the 'real' value of NOT. For example, a condition inside a 'NOT AND' group will get this called with $not = true, but if you put another 'NOT OR' group inside the first group, then a condition inside that will be called with $not = false. We need to use the real values, rather than the more natural use of the current value at this point inside the tree, so that the information displayed to users makes sense.

Parameters

bool	$not	Set true if we are inverting the condition
core_availability::info	$info	Item we're checking
bool	$grabthelot	Performance hint: if true, caches information required for all course-modules, to make the front page and similar pages work more quickly (works only for current user)
int	$userid	User ID to check availability for

Return values

result

Availability check result

filter_user_list()

core_availability\tree_node::filter_user_list	(	array	$users,
			$not,
		core_availability\info	$info,
		capability_checker	$checker
	)

Tests this condition against a user list.

Users who do not meet the condition will be removed from the list, unless they have the ability to view hidden activities/sections.

This function must be implemented if is_applied_to_user_lists returns true. Otherwise it will not be called.

The function must operate efficiently, e.g. by using a fixed number of database queries regardless of how many users are in the list.

Within this function, if you need to check capabilities, please use the provided checker which caches results where possible.

Conditions do not need to check the viewhiddenactivities or viewhiddensections capabilities. These are handled by core_availability::info::filter_user_list.

Parameters

array	$users	Array of userid => object
bool	$not	True if this condition is applying in negative mode
core_availability::info	$info	Item we're checking
capability_checker	$checker

Return values

array

Filtered version of input array

Exceptions

coding_exception

If called on a condition that doesn't apply to user lists

get_user_list_sql()

core_availability\tree_node::get_user_list_sql	(		$not,
		core_availability\info	$info,
			$onlyactive
	)

Obtains SQL that returns a list of enrolled users that has been filtered by the conditions applied in the availability API, similar to calling get_enrolled_users and then filter_user_list.

As for filter_user_list, this ONLY filters out users with conditions that are marked as applying to user lists. For example, group conditions are included but date conditions are not included.

The returned SQL is a query that returns a list of user IDs. It does not include brackets, so you neeed to add these to make it into a subquery. You would normally use it in an SQL phrase like "WHERE u.id IN ($sql)".

The SQL will be complex and may be slow. It uses named parameters (sorry, I know they are annoying, but it was unavoidable here).

If there are no conditions, the returned result is array('', array()).

Conditions do not need to check the viewhiddenactivities or viewhiddensections capabilities. These are handled by core_availability::info::get_user_list_sql.

Parameters

bool	$not	True if this condition is applying in negative mode
core_availability::info	$info	Item we're checking
bool	$onlyactive	If true, only returns active enrolments

Return values

array

Array with two elements: SQL subquery and parameters array

Exceptions

coding_exception

If called on a condition that doesn't apply to user lists

include_after_restore()

core_availability\tree_node::include_after_restore	(		$restoreid,
			$courseid,
		base_logger	$logger,
			$name,
		base_task	$task
	)

Checks whether this node should be included after restore or not.

The node may be removed depending on restore settings, which you can get from the $task object.

By default nodes are still included after restore.

Parameters

string	$restoreid	Restore ID
int	$courseid	ID of target course
base_logger	$logger	Logger for any warnings
string	$name	Name of this item (for use in warning messages)
base_task	$task	Current restore task

Return values

bool	True if there was any change

Reimplemented in availability_group\condition, and availability_grouping\condition.

is_applied_to_user_lists()

core_availability\tree_node::is_applied_to_user_lists

(

)

Checks whether this condition applies to user lists.

The default is false (the condition is used to control access, but does not prevent the student from appearing in lists).

For example, group conditions apply to user lists: we do not want to include a student in a list of users if they are prohibited from accessing the activity because they don't belong to a relevant group. However, date conditions do not apply - we still want to show users in a list of people who might have submitted an assignment, even if they are no longer able to access the assignment in question because there is a date restriction.

The general idea is that conditions which are likely to be permanent (group membership, user profile) apply to user lists. Conditions which are likely to be temporary (date, grade requirement) do not.

Conditions which do apply to user lists must implement the filter_user_list function.

Return values

bool	True if this condition applies to user lists

Reimplemented in core_availability\tree, availability_group\condition, availability_grouping\condition, and availability_profile\condition.

is_available_for_all()

core_availability\tree_node::is_available_for_all (   $not = false )

abstract

Checks whether this condition is actually going to be available for all users under normal circumstances.

Normally, if there are any conditions, then it may be hidden. However in the case of date conditions there are some conditions which will definitely not result in it being hidden for anyone.

Parameters

bool

$not

Set true if we are inverting the condition

Return values

bool	True if condition will return available for everyone

Reimplemented in core_availability\condition, core_availability\tree, and availability_date\condition.

save()

core_availability\tree_node::save ( )

abstract

Saves tree data back to a structure object.

Return values

stdClass

Structure object (ready to be made into JSON format)

Reimplemented in core_availability\tree, availability_completion\condition, availability_date\condition, availability_grade\condition, availability_group\condition, availability_grouping\condition, and availability_profile\condition.

unique_sql_parameter()

static core_availability\tree_node::unique_sql_parameter ( array &  $params,   $value  )

staticprotected

Utility function for generating SQL parameters (because we can't use ? parameters because get_enrolled_sql has infected us with horrible named parameters).

Parameters

array	$params	Params array (value will be added to this array)
string | int	$value	Value

Return values

SQL	code for the parameter, e.g. ':pr1234'

update_after_restore()

core_availability\tree_node::update_after_restore	(		$restoreid,
			$courseid,
		base_logger	$logger,
			$name
	)

Updates this node after restore, returning true if anything changed.

The default behaviour is simply to return false. If there is a problem with the update, $logger can be used to output a warning.

Note: If you need information about the date offset, call core_availability::info::get_restore_date_offset($restoreid). For information on the restoring task and its settings, call core_availability::info::get_restore_task($restoreid).

Parameters

string	$restoreid	Restore ID
int	$courseid	ID of target course
base_logger	$logger	Logger for any warnings
string	$name	Name of this item (for use in warning messages)

Return values

bool	True if there was any change

Reimplemented in availability_date\condition, core_availability\tree, availability_completion\condition, availability_grade\condition, availability_group\condition, and availability_grouping\condition.

update_dependency_id()

core_availability\tree_node::update_dependency_id (   $table,   $oldid,   $newid  )

abstract

Updates this node if it contains any references (dependencies) to the given table and id.

Parameters

string	$table	Table name e.g. 'course_modules'
int	$oldid	Previous ID
int	$newid	New ID

Return values

bool	True if it changed, otherwise false

Reimplemented in core_availability\condition, core_availability\tree, availability_completion\condition, availability_grade\condition, availability_group\condition, and availability_grouping\condition.

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The documentation for this class was generated from the following file:

• availability/classes/tree_node.php