流接口模式
<h3>流接口模式目的</h3>
<ul>
<li>用来编写易于阅读的代码，就像自然语言一样（如英语）</li>
</ul>
<h2>代码示例</h2>
<pre><code class="language-PHP"><?php
class Sql
{
/**
* @var array
*/
private $fields = [];
/**
* @var array
*/
private $from = [];
/**
* @var array
*/
private $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)
);
}
}
$query = (new Sql())
->select(['foo', 'bar'])
->from('foobar', 'f')
->where('f.bar = ?');
$this->assertEquals('SELECT foo, bar FROM foobar AS f WHERE f.bar = ?', (string) $query);
</code></pre>