path: root/dozentenmodul/src/main/java/org/openslx/dozmod/util/MapHelper.java

package org.openslx.dozmod.util;

import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.apache.log4j.Logger;

public class MapHelper {

	private static final Logger LOGGER = Logger.getLogger(MapHelper.class);

	private MapHelper() {}

	public static <T> boolean hasChanged(final Map<String, T> oldMap, final Map<String, T> newMap) {
		// build list of users that were added, if any return true
		if (oldMap.size() != newMap.size())
			return true;

		// no changes in the users, lets check for changes in each users permissions
		for (Entry<String, T> entry : oldMap.entrySet()) {
			T current = entry.getValue();
			T other = newMap.get(entry.getKey());
			if (!current.equals(other))
				return true;
		}
		// everything was the same if we are still here
		return false;
	}
	private static <T> Set<String> getAddedUsers(final Map<String, T> oldMap, final Map<String, T> newMap) {
		Set<String> addedUsers = new HashSet<String>(newMap.keySet());
		addedUsers.removeAll(oldMap.keySet());
		return addedUsers;
	}
	private static <T> Set<String> getRemovedUsers(final Map<String, T> oldMap, final Map<String, T> newMap) {
		Set<String> removedUsers = new HashSet<String>(oldMap.keySet());
		removedUsers.removeAll(newMap.keySet());
		return removedUsers;
	}
}