src/main/java/org/seedstack/jpa/internal/specification/JpaTranslationContext.java
@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.