public T_CHILD_CLASS enabled(final Boolean enabled) {
            if (Boolean.TRUE.equals(enabled)) {
                this.enabled = null;
            } else {
                this.enabled = enabled;
            }
            return self();
        }
@param enabled Sets the terms state to enabled if true or null, disabled if false
@return The Builder Builder, enabling method chaining
stroom-query/stroom-query-api/src/main/java/stroom/query/api/ExpressionItem.java