/*标识对象模式这个模式主要功能就是创建sql语句中的wehre条件字符串的，下面直接看代码和注释:*/namespace woo\mapper;//字段对象class Field {    protected $name = null;          //字段名称    protected $operator = null;         //操作符        protected $comps = array();         //存放条件的数组        protected $incomplete = false;     //检查条件数组是否有值        function __construct ($name){        $this->name= $name;    }        //添加where 条件    function addTest($operator,$value){        $this->comps[] = array('name'=>$this->name,'operator'=>$operator,'value'=>$value);    }        //获取存放条件的数组    function getComps(){        return $this->comps;    }        function isIncomplete(){        return empty($this->comps);    }}//标识对象class IdentityObject {    protected $currentfield = null;        //当前操作的字段对象    protected $fields = array();        //字段集合    private $and = null;    private $enforce = array();            //限定的合法字段                function __construct($field = null, array $enforce = null){        if(!is_null($enforce)){            $this->enforce = $enforce;        }        if(!is_null($field)){            $this->field($field);        }    }        //获取限定的合法字段    function getObjectFields(){        return $this->enforce;    }        //主要功能为设置当前需要操作的对象    function field($fieldname){        if(!$this->isVoid()&& $this->currentfield->isIncomplete()){            throw new \Exception("Incomplete field");        }        $this->enforceField($fieldname);        if(isset($this->fields[$fieldname]){            $this->currentfield = $this->fields[$fieldname];        } else {            $this->currentfield = new Field($fieldname);            $this->fields[$fieldname] = $this->currentfield;        }        return $this;                    //采用连贯语法    }        //字段集合是否为空    function isVoid(){        return empty($this->fields);    }        //检查字段是否合法    function enforceField ($fieldname){        if(!in_array($fieldname,$this->enforce) && !empty($this->enforce)){            $forcelist = implode(',',$this->enforce);            throw new \Exception("{
   $fieldname} not a legal field {
   $forcelist}");        }    }            //向字段对象添加where条件    function eq($value){        return $this->operator("=",$value);    }        function lt($value){        return $this->operator("<",$value);    }        function gt($value){        return $this->operator(">",$value);    }        //向字段对象添加where条件    private function operator($symbol,$value){        if($this->isVoid){            throw new \Exception("no object field defined");        }        $this->currentfield->addTest($symbol,$value);        return $this;                                     //采用连贯语法    }        //获取此类中所有字段对象集合的where条件数组    function getComps(){        $ret = array();        foreach($this->fields as $key => $field){            $ret = array_merge($ret,$field->getComps());        }        return $ret;    }}//客户端代码$idobj = new IdentityObject ();$idobj->field("name")->eq("The Good Show")->field("start")->gt(time())->lt(time()+(24*60*60));$test = $idobj->getComps();var_dump($test);//输出类似下面的内容/*array{    array('name'=>'name','operator'=>'=','value'=>'The Good Show'),    array('name'=>'start','operator'=>'>','value'=>'123456'),   //123456表示time()函数输出的时间戳    array('name'=>'start','operator'=>'<','value'=>'123456')}*/