title: Java Swing: Implementing a validity check of input values
body: <p>In my Swing application, the user must insert numbers and values, before switching to the next window. Now as a clean program should, I check every input if its valid or not, and if not, an error message is displayed and the next window does not open.</p>
  
  <p>The structure of this check is as following (example):</p>
  
  <pre><code>Button buttonToOpenNextWindow = new JButton("next");
  button.addActionListener(new ActionListener(){
  
      public void actionPerformed(ActionEvent e){
          if(checkValidty){
              // (...)
              new WindowA();
              frame.dispose(); // (*)
          }
      }
  });
  </code></pre>
  
  <p><strong>(*) Note:</strong> I know that the principle of multiple JFrames is ugly, and I'm on to change that, but for this question it's irrelevant.</p>
  
  <p>Now the focus of this question is this <code>checkValidity()</code>, which I structured like this:</p>
  
  <pre><code>private boolean checkValidity(){
  
      // check input 1
      try{
          Integer.parseInt(textField1.getText());
      }catch (NumberFormatException e){
          new ErrorDialog("input 1 is invalid!"); // own implemented dialog
          return false;
      }
  
      // check input 2
      try{
          Integer.parseInt(textField2.getText());
      }catch (NumberFormatException e){
          new ErrorDialog("input 2 is invalid!"); // own implemented dialog
          return false;
      }
  
      // (...)
  
      // check input n
      try{
          Integer.parseInt(textField_n.getText());
      }catch (NumberFormatException e){
          new ErrorDialog("input n is invalid!"); // own implemented dialog
          return false;
      }
      return true;
  }
  </code></pre>
  
  <p>This works exactly as I want, BUT the code itself is very ugly, because having multiple input options the method gets 200, 300 or more lines long (as I do not only check if e.g. it's a number, but also if the number makes sense in context of the program logic and so on). Is there a Swing -own method to check such things? Or has anyone a better idea how to realize exactly this functionality with split methods?</p>