public void setExpression(final ExpressionOperator expression, final Runnable onSetExpression) {
        validateExpression(expression, expression2 -> {
            this.criteria.setExpression(expression2);
            NullSafe.run(onSetExpression);
        });
    }
@param onSetExpression Called after the expression has been successfully
                       validated and set on the criteria. Can be null.
stroom-core-client/src/main/java/stroom/data/client/presenter/AbstractMetaListPresenter.java