var Class = require('../utils/Class'); 
var List = require('../structs/List'); 
var PluginCache = require('../plugins/PluginCache'); 
var SceneEvents = require('../scene/events'); 
var StableSort = require('../utils/array/StableSort'); 
var DisplayList = new Class({ 
Extends: List,
initialize: function DisplayList(scene){ 
List.call(this, scene); 
this.sortChildrenFlag = false ; 
this.scene = scene; 
this.systems = scene.sys; 
scene.sys.events.once(SceneEvents.BOOT, this.boot, this); 
scene.sys.events.on(SceneEvents.START, this.start, this); 
} 
,
boot: function (){ 
this.systems.events.once(SceneEvents.DESTROY, this.destroy, this); 
} 
,
start: function (){ 
this.systems.events.once(SceneEvents.SHUTDOWN, this.shutdown, this); 
} 
,
queueDepthSort: function (){ 
this.sortChildrenFlag = true ; 
} 
,
depthSort: function (){ 
if (this.sortChildrenFlag) { 
StableSort.inplace(this.list, this.sortByDepth); 
this.sortChildrenFlag = false ; 
} 
} 
,
sortByDepth: function (childA, childB){ 
return childA._depth - childB._depth; 
} 
,
getChildren: function (){ 
return this.list; 
} 
,
shutdown: function (){ 
var i = _AN_Read_length('length', this.list); 
while (i-- ){ 
this.list[i].destroy(true ); 
} 
this.list.length = 0; 
this.systems.events.off(SceneEvents.SHUTDOWN, this.shutdown, this); 
} 
,
destroy: function (){ 
this.shutdown(); 
this.scene.sys.events.off(SceneEvents.START, this.start, this); 
this.scene = null ; 
this.systems = null ; 
} 
}
); 
PluginCache.register('DisplayList', DisplayList, 'displayList'); 
module.exports = DisplayList;