title: Extension point for providing custom content assist processors in Eclipse
body: <p>I am writing eclipse plugin to add better support for properties files. One of the missing piece is content-assist ... I'd like to show matching properties keys when user starts typing some string and presses content assist key.</p>
  
  <p>For example, when I have property <code>hello = world</code> in one of my properties files, and I start typing <code>format("hel</code> and hit <kbd>CTRL</kbd>+<kbd>SPACE</kbd> now, I'd like to see available <code>hello</code> property.</p>
  
  <p>My problem is that I cannot find correct extension point to provide custom content assist processor. How can I provide my own content assist processor for text files? I'd like to make it work mainly in Java, JSP and XML files.</p>