PHP设计模式 PHP 连贯接口模式
目的
用来编写易于阅读的代码，就像自然语言一样（如英语）
例子
- Doctrine2 的 QueryBuilder，就像下面例子中类似
- PHPUnit 使用连贯接口来创建 mock 对象
UML 图
代码
Sql.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\FluentInterface;
class Sql implements \Stringable
{
private array $fields = [];
private array $from = [];
private array $where = [];
public function select(array $fields): Sql
{
$this->fields = $fields;
return $this;
}
public function from(string $table, string $alias): Sql
{
$this->from[] = $table . ' AS ' . $alias;
return $this;
}
public function where(string $condition): Sql
{
$this->where[] = $condition;
return $this;
}
public function __toString(): string
{
return sprintf(
'SELECT %s FROM %s WHERE %s',
join(', ', $this->fields),
join(', ', $this->from),
join(' AND ', $this->where)
);
}
}
测试
Tests/FluentInterfaceTest.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\FluentInterface\Tests;
use DesignPatterns\Structural\FluentInterface\Sql;
use PHPUnit\Framework\TestCase;
class FluentInterfaceTest extends TestCase
{
public function testBuildSQL()
{
$query = (new Sql())
->select(['foo', 'bar'])
->from('foobar', 'f')
->where('f.bar = ?');
$this->assertSame('SELECT foo, bar FROM foobar AS f WHERE f.bar = ?', (string) $query);
}
}