Making forms object-oriented Page 4

Implementing the FormProcessor class

But this was still quite far from our original subject, we were talking about
object-oriented forms here, remember? Let’s have a look at FormProcessor and
see what’s under its hood. I had to strip the code of PHPDoc-style comments,
because I think it requires step-by-step explanations, while reading through
the comments in arbitrary order might confuse. Version of this source with PHPDoc
comments is available for download from
here.

<?php
  /**
  * An abstract class implementing generic functionality for processing user's input
  *
  * This class encapsulates generic functions for working 
  * with data coming from user forms. Descendants must only override certain 
  * functions that perform context-specific tasks, like custom checking of 
  * data, storing correct data, etc.
  *
  * @author Yuri Makassiouk <[email protected]>, 
  *  Mission & Media <[email protected]>
  */
  class FormProcessor {
    var $Name;
    var $FirstTime;
    var $Values;
    var $Errors = array();
    var $ErrorMessageFormat = '<br>%s';
    var $wizardPage;
    var $fieldPrefix = 'mm_form_data_';
    function FormProcessor($Name, $wPage='') {
      $this->Name = $Name;
      $this->wizardPage = $wPage;
      $this->Values = $GLOBALS[$this->fieldPrefix.$this->Name];
      $this->FirstTime = (count($this->Values) == 0);
      if (!$this->FirstTime)
        $this->CustomCheck();
      if ($this->IsCompleted()) {
        $this->StoreData();
        $GLOBALS['wizardPage'] = $this->NextWizardPage();
      } 
      else
        $this->DisplayForm();
    }
    function IsCompleted() {
      return (!$this->FirstTime && count($this->Errors)<=0);
    }
    function CustomCheck() {}
    //abstract
    function DisplayForm() {}
    //abstract
    function NextWizardPage() {}
    //abstract
    function StoreData() {}
    //abstract
    function Additional() {
      if ($this->wizardPage) :
    ?>
    <input type="Hidden" name="wizardPage" value="<?php echo $this->wizardPage?>">
    <?php endif;
    }
    function Set($Name, $Value) {
      $this->$Name = $Value;
    }
    function ErrorReport($Name) {
      if (isset($this->Errors[$Name]))
        printf($this->ErrorMessageFormat, $this->Errors[$Name]);
    }
    function GetInitialValue($Name) {
      if (isset($this->Values[$Name]))
        return $this->Values[$Name];
      else
        return false;
    }
    function InitialValue($Name) {
      echo $this->GetInitialValue($Name);
    }
  }
?>