Flex 通用的表格过滤处理

在上文“Flex AdvancedDataGrid表格过滤”中介绍了flat data和HierarchicalData的过滤处理，并且提到所谓表格过滤实质上就是表格的数据源过滤。本文继续假设表格的最终数据源就是Arraycollection，则表格过滤通用化处理，就是arraycollection的filterFunction通用化处理。

思路如下：

1）构造过滤条件列表；

2）过滤函数实现，根据过滤条件列表逐个进行验证，最终返回true或者false验证结果；

实现如下：

1）构造过滤条件列表

条件列表本身是一个array Collection，假设为conditions，其放置的对象为条件过滤对象，主要有4个元素：

column:要过滤的列名；

operator：操作符，有等于(=)、小于(<)、大于(>)、不等于(!=)、小于等于(<=)、大于等于(>=)、like(.)、not like(!.);

comparevalue:比较值

logical：逻辑值，and、or；

2）filterFunction实现

为了增加代码松耦合，将过滤处理的核心代码写成了一个类DataGridFilter，代码如下：

public class DataGridFilter { private static const LOGICAL_AND:String = "AND"; private static const LOGICAL_OR:String = "OR"; // private static const OPERATOR_EQ:String = "="; private static const OPERATOR_LT:String = "<"; private static const OPERATOR_GT:String = ">"; private static const OPERATOR_LE:String = "<="; private static const OPERATOR_GE:String = ">="; private static const OPERATOR_NE:String = "!="; private static const OPERATOR_LIKE:String = "."; private static const OPERATOR_NOTLIKE:String = "!."; // public function DataGridFilter() { } public function isMatched(item:Object, conditions:ArrayCollection):Boolean{ var ismatched:Boolean = true; for(var i:int=0; i<conditions.length; i++){ if(i==0){ ismatched = isMatchedObject(item,conditions[i]); }else{ if(conditions[i-1]["logical"]==LOGICAL_AND){ ismatched = ismatched && isMatchedObject(item,conditions[i]); }else{ ismatched = ismatched || isMatchedObject(item,conditions[i]); } } } return ismatched; } private function isEQ(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1==value2; } } private function isLT(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1<value2; } } private function isGT(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1>value2; } } private function isLE(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1<=value2; } } private function isGE(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1>=value2; } } private function isNE(value1:Object, value2:Object):Boolean{ return true; } private function isLIKE(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1.indexOf(value2)>-1; } } private function isNOTLIKE(value1:Object, value2:Object):Boolean{ if(value1==null){ return false; }else{ return value1.indexOf(value2)==-1; } } public function isMatchedObject(item:Object, condition:Object):Boolean{ var value1:Object = item[condition["column"]]; var value2:Object = condition["comparevalue"]; switch(condition["operator"]){