title: how to get the position of a particular string in the editor that is currently opened?
body: <p>I m doing a project using eclipse plugin to create a IDE.</p>
  
  <p>I have a view which consists of a textbox,when i enter some text in it and press the add button the text should replace a particular string in the editor.
  I m able to find the current editor but i dono how to find the position of the string to be replaced.</p>
  
  <p>Can anyone help me in doing this?</p>