Class UBCollection

<Class Description>

Abstract
Package: ClipIt\urjc\backend
License: Affero General Public License v3
Author: Pablo Llinás Arnaiz <pebs74@gmail.com>, URJC JuxtaLearn Team
Located at UBCollection.php

Methods summary
`public static boolean`	# `add_items( integer $id, array $item_array, string $rel_name, boolean $exclusive = false )` Adds Items to a Collection. Adds Items to a Collection. Parameters `$id` `integer` $id Id from Collection to add Items to. `$item_array` `array` $item_array Array of Item Ids to add. `$rel_name` `string` $rel_name Name of the relationship to use. `$exclusive` `boolean` $exclusive Whether the added items have an exclusive relationship with the collection. Returns `boolean` Returns true if success, false if error
`public static boolean`	# `set_items( integer $id, array $item_array, string $rel_name, boolean $exclusive = false )` Sets Items to a Collection. Sets Items to a Collection. Parameters `$id` `integer` $id Id from Collection to add Items to. `$item_array` `array` $item_array Array of Item Ids to set. `$rel_name` `string` $rel_name Name of the relationship to use. `$exclusive` `boolean` $exclusive Whether the added items have an exclusive relationship with the collection. Returns `boolean` Returns true if success, false if error
`public static int[]\|boolean`	# `get_items( integer $id, string $rel_name, boolean $inverse = false )` Get Items from a Collection. Get Items from a Collection. Parameters `$id` `integer` $id Id from Collection to get Items from. `$rel_name` `string` $rel_name Name of the relationship linking the items. `$inverse` `boolean` $inverse Whether the Id specified is in the first (false) or second (true) term of the relationship. Returns `int[]\|boolean` Returns an array of Item IDs, or false if error.
`public static integer`	# `count_items( integer $id, string $rel_name, boolean $inverse = false, boolean $recursive = false )` Count the number of related items. Count the number of related items. Parameters `$id` `integer` $id Item to count related items with. `$rel_name` `string` $rel_name Name of the relationship `$inverse` `boolean` $inverse position of the Item in the relationship (first = false, seccond = true) `$recursive` `boolean` $recursive Whether to count recursively or not Returns `integer` Number of items related with the one specified.
`public static boolean`	# `remove_items( integer $id, array $item_array, string $rel_name )` Remove Items from a Collection. Remove Items from a Collection. Parameters `$id` `integer` $id Id from Collection to remove Items from. `$item_array` `array` $item_array Array of Item Ids to remove. `$rel_name` `string` $rel_name Name of the relationship to use. Returns `boolean` Returns true if success, false if error.
`public static boolean`	# `remove_all_items( integer $id, string $rel_name )` Remove all items from a collection. Remove all items from a collection. Parameters `$id` `integer` $id ID of the Collection to remove items from. `$rel_name` `string` $rel_name Name of the relationship to use. Returns `boolean` Returns true if success, false if error.
`public static`	# `set_timestamp( mixed $id1, mixed $id2, mixed $rel_name, mixed $timestamp )`
`public static`	# `get_timestamp( mixed $id1, mixed $id2, mixed $rel_name )`