import java.util.Set;


public class ResourcesManager {
	
	
	private Set<Resource> resources;
	
	
	
	public void changeResourceBy(Resource resource,int offset){
	
	}

}

import java.util.Set;


public class ResourcesManager {
	
	
	private Set<Resource> resources;
	
	
	
	public void changeResourceBy(AvailableResources resource,int offset){
	
	}

}

Fix resource parameter type