__callStatic

示例：

<?php
//演示通过使用__callStatic这一魔术方法来进行方法的动态创建和延迟绑定
//当调用findByLastname()方法时，可以动态的来生成相应的执行方法
abstract class ActiveRecord{
    protected static $table;
    protected $fieldvalues;
    public $select;
    
    static function findById($id){
        $query = "select * from "
                .static::$table
                ." where id = $id";
        return self::createDomain($query);
    }
    
    function __get($fieldname){
        return $this->fieldvalues[$fieldname];
    }
    
    static function __callstatic($method,$args) {
        $field = preg_replace('/^findBy(\w*)$/', '${1}', $method);
        $query = "select * from "
                .static::$table
                ." where $field = '$args[0]'";
        return self::createDomain($query);
    }
    
    private static function createDomain($query) {
        $klass = get_called_class();
        $domain = new $klass();
        $domain->fieldvalues = array();
        $domain->select = $query;
        foreach ($klass::$fields as $field => $type){
            $domain->fieldvalues[$field] = 'TODO:set from sql result';
        }
        return $domain;
    }
}

class Customer extends ActiveRecord{
    protected static $table = 'custdb';
    protected static $fields = array(
            'id'=>'int',
            'email'=>'varchar',
            'lastname'=>'varchar',
    );
}

class Sales extends ActiveRecord{
    protected static $table = 'salesdb';
    protected static $fields = array(
            'id'=>'int',
            'item'=>'varchar',
            'qty'=>'int',
    );
}

if(assert("select * from custdb where id = 123" == Customer::findById(123)->select)){
    echo 'select * from custdb where id = 123'."<br>";
} 
if(assert("TODO:set from sql result" == Customer::findById(123)->email)){
    echo 'TODO:set from sql result'."<br>";
}
if(assert("select * from salesdb where id = 321" == Sales::findById(321)->select)){
    echo 'select * from salesdb where id = 321'."<br>";
}
if(assert("select * from custdb where Lastname = 'Denoncourt'" == Customer::findByLastname('Denoncourt')->select)){
    echo "select * from custdb where Lastname = 'Denoncourt'"."<br>";
}

?>

TO BE CONTINUED...

参考文献

• PHP核心技术与最佳实践