diff --git a/tutorial.php b/tutorial.php
new file mode 100644
index 0000000..03252ae
--- /dev/null
+++ b/tutorial.php
@@ -0,0 +1,19 @@
+<?php
+
+// include vCard class files.
+require 'vCard.class.php';
+
+// create new vCard class.
+$card = new vCard();
+
+// set contact's datas.
+$card->set(array(
+    'first_name' => 'Yalçın',
+    'last_name' => 'Ceylan',
+    'cell_tel' => '+90 536 754 85 78',
+    'url' => 'http://www.yalcinceylan.net',
+    'email1' => 'yalcinceylan93@gmail.com',
+));
+
+// build and start download.
+$card->download();
\ No newline at end of file
diff --git a/vCard.class.php b/vCard.class.php
index c575de6..126d28b 100644
--- a/vCard.class.php
+++ b/vCard.class.php
@@ -7,115 +7,121 @@
 
 class vCard
 {
-    // An array of this vcard's contact data.
-    protected $data;
+
+    // An array of this vCard's contact data.
+    protected $data = array(
+        'display_name' => NULL,
+        'first_name' => NULL,
+        'last_name' => NULL,
+        'additional_name' => NULL,
+        'name_prefix' => NULL,
+        'name_suffix' => NULL,
+        'nickname' => NULL,
+        'title' => NULL,
+        'role' => NULL,
+        'department' => NULL,
+        'company' => NULL,
+        'work_po_box' => NULL,
+        'work_extended_address' => NULL,
+        'work_address' => NULL,
+        'work_city' => NULL,
+        'work_state' => NULL,
+        'work_postal_code' => NULL,
+        'work_country' => NULL,
+        'home_po_box' => NULL,
+        'home_extended_address' => NULL,
+        'home_address' => NULL,
+        'home_city' => NULL,
+        'home_state' => NULL,
+        'home_postal_code' => NULL,
+        'home_country' => NULL,
+        'office_tel' => NULL,
+        'home_tel' => NULL,
+        'cell_tel' => NULL,
+        'fax_tel' => NULL,
+        'pager_tel' => NULL,
+        'email1' => NULL,
+        'email2' => NULL,
+        'url' => NULL,
+        'photo' => NULL,
+        'birthday' => NULL,
+        'timezone' => NULL,
+        'sort_string' => NULL,
+        'note' => NULL,
+    );
+
     // Filename for download file naming.
     protected $filename;
+
     // vCard class: PUBLIC, PRIVATE, CONFIDENTIAL.
     protected $class;
+
     // vCard revision date.
     protected $revision_date;
+
     // The vCard gnerated.
     protected $card;
-  
-    /**
-     * The constructor.
-     */
-    public function __construct()
-    {
-        $this->data = array(
-            'display_name' => NULL,
-            'first_name' => NULL,
-            'last_name' => NULL,
-            'additional_name' => NULL,
-            'name_prefix' => NULL,
-            'name_suffix' => NULL,
-            'nickname' => NULL,
-            'title' => NULL,
-            'role' => NULL,
-            'department' => NULL,
-            'company' => NULL,
-            'work_po_box' => NULL,
-            'work_extended_address' => NULL,
-            'work_address' => NULL,
-            'work_city' => NULL,
-            'work_state' => NULL,
-            'work_postal_code' => NULL,
-            'work_country' => NULL,
-            'home_po_box' => NULL,
-            'home_extended_address' => NULL,
-            'home_address' => NULL,
-            'home_city' => NULL,
-            'home_state' => NULL,
-            'home_postal_code' => NULL,
-            'home_country' => NULL,
-            'office_tel' => NULL,
-            'home_tel' => NULL,
-            'cell_tel' => NULL,
-            'fax_tel' => NULL,
-            'pager_tel' => NULL,
-            'email1' => NULL,
-            'email2' => NULL,
-            'url' => NULL,
-            'photo' => NULL,
-            'birthday' => NULL,
-            'timezone' => NULL,
-            'sort_string' => NULL,
-            'note' => NULL,
-        );
-
-        return true;
-    }
 
     /**
-     * Global setter.
-     * 
-     * @param string $key
-     *   Name of the property.
-     * @param mixed $value
-     *   Value to set.
-     * 
+     * vCard contact data setter.
+     *
+     * @param $key
+     * @param null $value
      * @return vCard
-     *   Return itself.
      */
-    public function set($key, $value)
+    public function set($key, $value = null)
     {
-        // Check if the specified property is defined.
-        if (property_exists($this, $key) && $key != 'data') {
-            $this->{$key} = trim($value);
-            return $this;
-        } elseif (property_exists($this, $key) && $key == 'data') {
-            foreach ($value as $v_key => $v_value) {
-                $this->{$key}[$v_key] = trim($v_value);
+
+        if ( is_array($key) )
+        {
+            foreach ($key as $_key => $_value)
+            {
+                $this->data[$_key] = trim($_value);
             }
-            return $this;
-        } else {
-            return FALSE;
         }
+        else if ( !is_null($value) )
+        {
+            $this->data[$key] = trim($value);
+        }
+
+        return $this;
+
     }
 
     /**
      * Checks all the values, builds appropriate defaults for
-     * missing values and generates the vcard data string.
+     * missing values and generates the vCard data string.
      */  
-    function build()
+    protected function build()
     {
-        if (!$this->class) {
+
+        if (!$this->class)
+        {
             $this->class = 'PUBLIC';
         }
-        if (!$this->data['display_name']) {
+
+        if (!$this->data['display_name'])
+        {
             $this->data['display_name'] = $this->data['first_name'] . ' ' . $this->data['last_name'];
         }
-        if (!$this->data['sort_string']) {
+
+        if (!$this->data['sort_string'])
+        {
             $this->data['sort_string'] = $this->data['last_name'];
         }
-        if (!$this->data['sort_string']) {
+
+        if (!$this->data['sort_string'])
+        {
             $this->data['sort_string'] = $this->data['company'];
         }
-        if (!$this->data['timezone']) {
+
+        if (!$this->data['timezone'])
+        {
             $this->data['timezone'] = date("O");
         }
-        if (!$this->revision_date) {
+
+        if (!$this->revision_date)
+        {
             $this->revision_date = date('Y-m-d H:i:s');
         }
 
@@ -131,19 +137,25 @@ function build()
             . $this->data['additional_name'] . ";"
             . $this->data['name_prefix'] . ";"
             . $this->data['name_suffix'] . "\r\n";
-        if ($this->data['nickname']) {
+
+        if ($this->data['nickname'])
+        {
             $this->card .= "NICKNAME:" . $this->data['nickname'] . "\r\n";
         }
-  	    if ($this->data['title']) {
+  	    if ($this->data['title'])
+        {
             $this->card .= "TITLE:" . $this->data['title'] . "\r\n";
         }
-        if ($this->data['company']) {
+        if ($this->data['company'])
+        {
             $this->card .= "ORG:" . $this->data['company'];
         }
-        if ($this->data['department']) {
+        if ($this->data['department'])
+        {
             $this->card .= ";".$this->data['department'];
         }
-  	    $this->card .= "\r\n";
+
+        $this->card .= "\r\n";
 
   	    if ($this->data['work_po_box'] || $this->data['work_extended_address']
   	        || $this->data['work_address'] || $this->data['work_city']
@@ -172,75 +184,96 @@ function build()
   	                . $this->data['home_postal_code'] . ";"
   	                . $this->data['home_country'] . "\r\n";
    	    }
-   	    if ($this->data['email1']) {
+
+   	    if ($this->data['email1'])
+        {
             $this->card .= "EMAIL;type=INTERNET,pref:" . $this->data['email1'] . "\r\n";
    	    }
-   	    if ($this->data['email2']) {
+
+        if ($this->data['email2'])
+        {
             $this->card .= "EMAIL;type=INTERNET:" . $this->data['email2'] . "\r\n";
         }
-   	    if ($this->data['office_tel']) {
+
+        if ($this->data['office_tel'])
+        {
             $this->card .= "TEL;type=WORK,voice:" . $this->data['office_tel'] . "\r\n";
    	    }
-   	    if ($this->data['home_tel']) {
+
+   	    if ($this->data['home_tel'])
+        {
             $this->card .= "TEL;type=HOME,voice:" . $this->data['home_tel'] . "\r\n";
    	    }
-   	    if ($this->data['cell_tel']) {
+
+        if ($this->data['cell_tel'])
+        {
             $this->card .= "TEL;type=CELL,voice:" . $this->data['cell_tel'] . "\r\n";
    	    }
-   	    if ($this->data['fax_tel']) {
+
+        if ($this->data['fax_tel'])
+        {
             $this->card .= "TEL;type=WORK,fax:" . $this->data['fax_tel'] . "\r\n";
    	    }
-   	    if ($this->data['pager_tel']) {
+
+        if ($this->data['pager_tel'])
+        {
             $this->card .= "TEL;type=WORK,pager:" . $this->data['pager_tel'] . "\r\n";
    	    }
-   	    if ($this->data['url']) {
+
+        if ($this->data['url'])
+        {
             $this->card .= "URL;type=WORK:" . $this->data['url'] . "\r\n";
    	    }
-   	    if ($this->data['birthday']) {
+
+        if ($this->data['birthday'])
+        {
             $this->card .= "BDAY:" . $this->data['birthday'] . "\r\n";
    	    }
-   	    if ($this->data['role']) {
+
+        if ($this->data['role'])
+        {
             $this->card .= "ROLE:" . $this->data['role'] . "\r\n";
    	    }
-   	    if ($this->data['note']) {
+
+        if ($this->data['note'])
+        {
             $this->card .= "NOTE:" . $this->data['note'] . "\r\n";
    	    }
-   	    $this->card .= "TZ:" . $this->data['timezone'] . "\r\n";
-   	    $this->card .= "END:VCARD\r\n";
+
+        $this->card .= "TZ:" . $this->data['timezone'] . "\r\n";
+
+        $this->card .= "END:VCARD\r\n";
+
     }
-  
+
     /**
-     * Streams the vcard to the browser client.
+     * Streams the vCard to the browser client.
      */
-    function download()
+    public function download($filename = null)
     {
-        if (!$this->card) {
-            $this->build();
-        }
 
-        if (!$this->filename) {
-            $this->filename = $this->data['display_name'];
-        }
+        if (!$this->card) $this->build();
 
-        $this->filename = str_replace(' ', '_', $this->filename);
+        $this->filename = preg_replace('/\s+/', '_', ($filename ? $filename : $this->data['display_name']));
 
         header("Content-type: text/directory");
         header("Content-Disposition: attachment; filename=" . $this->filename . ".vcf");
         header("Pragma: public");
+
         echo $this->card;
 
-        return TRUE;
     }
 
     /**
-     * Show the vcard.
+     * Show the vCard.
      */
-    function show()
+    public function show()
     {
-        if (!$this->card) {
-            $this->build();
-        }
+
+        if (!$this->card) $this->build();
 
         return $this->card;
+
     }
+
 }