Question

我正在尝试为项目构建一些类，我想知道如何实现以下目标。我不确定如何用语言问这个，但我会提供一个例子：

class Table{
    private $name;
    private $fields = [];

    public function addField(Field $field){
        $this->fields[$field->getName()] = $field;
    }

    public function getName(){
        return $this->name;
    }
}

class Field{
    private $name;

    public function getName(){
        return $this->name;
    }

    public function getTableName(){
        //return Table::getName
    }

    public function getTable(){
        //return a ref to the Table object
    }

}

$table = new Table();
$field = new Field();
$table->addField($field);

我想在这里实现，一旦将$字段添加到$ table，就有某种方法从$ field对象中的任何方法获取$ table的引用

我非常感谢任何帮助或想法如何重组它，以便我可以实现我的目标

提前谢谢

Answer 1

class Table{
    private $name;
    private $fields = [];

    public function addField(Field $field){
        $this->field->setTable($this);
        $this->fields[$field->getName()] = $field;
    }

    public function getName(){
        return $this->name;
    }
}

class Field{
    private $name;
    private $relatedTable;

    public function getName(){
        return $this->name;
    }

    public function setName($name){
        $this->name = $name;
    }

    public function getTableName(){
        return $this->relatedTable->getName();
    }

    public function getTable(){
        return $this->relatedTable;
    }

    public function setTable(Table $table){
        $this->relatedTable = $table;
    }

}

$field = new Field;
$field->setName('Field1');
$table = new Table;
$table->addField($field);
echo $field->getTable()->getName();

虽然你必须要知道当你将一个对象传递给一个函数时，它会被“引用”传递（我知道还有另一个术语。）

// in case you're running it in a for loop
$field = new Field;
$table = new Table;
for($i = 0; $i < 3; $i++)
{
    $field->setName("Field{$i}");
    $table->addField(clone $field); // notice the clone there.
}

我认为这种方法与 Observer Pattern

类似

从成员对象获取类引用

1 个答案: