@SuppressWarnings("unchecked")
    public <E> Expression<E> pickExpression() {
        Preconditions.checkState(this.expression != null, "No expression has been set");
        Expression<E> result = (Expression<E>) this.expression;
        expression = null;
        return result;
    }
@SuppressWarnings("unchecked")
    public <E> Expression<E> pickExpression() {
        Preconditions.checkState(this.expression != null, "No expression has been set");
        Expression<E> result = (Expression<E>) this.expression;
        expression = null;
        return result;
    }
@ SuppressWarnings ( "unchecked" ) public < E > Expression < E > pickExpression ( ) { Preconditions . checkState ( this . expression != null , "No expression has been set" ) ; Expression < E > result = ( Expression < E > ) this . expression ; expression = null ; return result ; }
Returns the expression currently active in the building context.

@param <E> the type of the expression.
@return the JPA expression.
Returns the expression currently active in the building context .