I feel that, with the things that happened in Cologne and a number of other incidents Slovaia should close its borders. At least they should do it temporarily until the rest of Europe gets the whole migrant situation sorted out. It would be smart of them to do this because of national and international security.
They should refuse entry of any migration that they deem undesirable. It's their country, and their right to refuse entry. Perhaps, that's not the friendliest way to make friends on the world stage, but you have to respect a country's right to sovereignty. If they feel that allowing undocumented migrants is unsafe, they should protect their citizens.
There are millions of Muslims from all over the world, and almost all of them are good people. There are bad people from every group. To assume that all Muslims are terrorists, or even that Muslims are more likely to be terrorists than members of other groups, is just completely wrong. The vast majority of terrorist attacks in the U.S. and Europe in the last 30 to 40 years have been committed by non-Muslims. Not letting Muslims into the country would be discriminatory, unfair and based on false beliefs.
Putting a blanket ban on entry for an entire group of people is not a great policy. Instead, screen migrants or make sure they understand the country's customs and laws before they are permitted. This, along with letting in only a maximum, would reduce the number of undesired types while letting in those who need the safety.