PHP7 FluentInterface

Structural/FluentInterface/Sql.php

@@ -2,79 +2,51 @@
 
 namespace DesignPatterns\Structural\FluentInterface;
 
-/**
- * class SQL.
- */
 class Sql
 {
     /**
      * @var array
      */
-    protected $fields = array();
+    private $fields = [];
 
     /**
      * @var array
      */
-    protected $from = array();
+    private $from = [];
 
     /**
      * @var array
      */
-    protected $where = array();
+    private $where = [];
 
-    /**
-     * adds select fields.
-     *
-     * @param array $fields
-     *
-     * @return SQL
-     */
-    public function select(array $fields = array())
+    public function select(array $fields): Sql
     {
         $this->fields = $fields;
 
         return $this;
     }
 
-    /**
-     * adds a FROM clause.
-     *
-     * @param string $table
-     * @param string $alias
-     *
-     * @return SQL
-     */
-    public function from($table, $alias)
+    public function from(string $table, string $alias): Sql
     {
         $this->from[] = $table.' AS '.$alias;
 
         return $this;
     }
 
-    /**
-     * adds a WHERE condition.
-     *
-     * @param string $condition
-     *
-     * @return SQL
-     */
-    public function where($condition)
+    public function where(string $condition): Sql
     {
         $this->where[] = $condition;
 
         return $this;
     }
 
-    /**
-     * Gets the query, just an example of building a query,
-     * no check on consistency.
-     *
-     * @return string
-     */
-    public function getQuery()
+    public function __toString(): string
     {
-        return 'SELECT '.implode(',', $this->fields)
-                .' FROM '.implode(',', $this->from)
-                .' WHERE '.implode(' AND ', $this->where);
+        return sprintf(
+            'SELECT %s FROM %s WHERE %s',
+            join(', ', $this->fields),
+            join(', ', $this->from),
+            join(' AND ', $this->where)
+        );
     }
 }