src/main/java/ognl/EvaluationPool.java
public Evaluation create(SimpleNode node, Object source)
    {
        return create(node, source, false);
    }
public Evaluation create(SimpleNode node, Object source)
    {
        return create(node, source, false);
    }
Returns an Evaluation that contains the node, source and whether it
is a set operation.  If there are no Evaluation objects in the
pool one is created and returned.