2.8. Fluent Interface¶
2.8.1. Purpose¶
To write code that is easy readable just like sentences in a natural language (like English).
2.8.2. Examples¶
- Doctrine2’s QueryBuilder works something like that example class below
- PHPUnit uses fluent interfaces to build mock objects
- Yii Framework: CDbCommand and CActiveRecord use this pattern, too
2.8.3. UML Diagram¶
2.8.4. Code¶
You can also find these code on GitHub
Sql.php
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namespace DesignPatterns\Structural\FluentInterface;
/**
* class SQL
*/
class Sql
{
/**
* @var array
*/
protected $fields = array();
/**
* @var array
*/
protected $from = array();
/**
* @var array
*/
protected $where = array();
/**
* adds select fields
*
* @param array $fields
*
* @return SQL
*/
public function select(array $fields = array())
{
$this->fields = $fields;
return $this;
}
/**
* adds a FROM clause
*
* @param string $table
* @param string $alias
*
* @return SQL
*/
public function from($table, $alias)
{
$this->from[] = $table . ' AS ' . $alias;
return $this;
}
/**
* adds a WHERE condition
*
* @param string $condition
*
* @return SQL
*/
public function where($condition)
{
$this->where[] = $condition;
return $this;
}
/**
* Gets the query, just an example of building a query,
* no check on consistency
*
* @return string
*/
public function getQuery()
{
return 'SELECT ' . implode(',', $this->fields)
. ' FROM ' . implode(',', $this->from)
. ' WHERE ' . implode(' AND ', $this->where);
}
}
|
2.8.5. Test¶
Tests/FluentInterfaceTest.php
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namespace DesignPatterns\Structural\FluentInterface\Tests;
use DesignPatterns\Structural\FluentInterface\Sql;
/**
* FluentInterfaceTest tests the fluent interface SQL
*/
class FluentInterfaceTest extends \PHPUnit_Framework_TestCase
{
public function testBuildSQL()
{
$instance = new Sql();
$query = $instance->select(array('foo', 'bar'))
->from('foobar', 'f')
->where('f.bar = ?')
->getQuery();
$this->assertEquals('SELECT foo,bar FROM foobar AS f WHERE f.bar = ?', $query);
}
}
|