title: boolean expression parser in java
body: <p><strong>Are there any java libraries or techniques to parsing boolean expressions piecemeal?</strong></p>
  
  <p>What I mean is given an expression like this:</p>
  
  <p><code>T &amp;&amp; ( F || ( F &amp;&amp; T ) )</code></p>
  
  <p>It could be broken down into a expression tree to show which token caused the 'F' value, like so (<em>maybe</em> something like this):</p>
  
  <pre><code>T &amp;&amp;               &lt;- rhs false
      ( F ||         &lt;- rhs false
          ( F &amp;&amp; T ) &lt;- eval, false
      )
  </code></pre>
  
  <p>I am trying to communicate boolean expression evaluations to non-programmers. I have poked around with Anlr, but I couldn't get it to do much (it seems to have a bit of a learning curve). </p>
  
  <p>I'm not opposed to writing it myself, but I'd rather not reinvent the wheel.</p>