SpringSecurity Voter granting only access when it is night.

NightVoter.java

public class NightVoter implements AccessDecisionVoter {

	private String rolePrefix = "ROLE_";

	private static final int SUNRISE_HOUR = 9;
	private static final int SUNSET_HOUR = 21; 
	
	public String getRolePrefix() {
		return rolePrefix;
	}

	/**
	 * Allows the default role prefix of <code>ROLE_</code> to be overridden.
	 * May be set to an empty value, although this is usually not desirable.
	 * 
	 * @param rolePrefix
	 *            the new prefix
	 */
	public void setRolePrefix(String rolePrefix) {
		this.rolePrefix = rolePrefix;
	}

	public boolean supports(ConfigAttribute attribute) {
		if ((attribute.getAttribute() != null)
				&& attribute.getAttribute().startsWith(getRolePrefix())) {
			return true;
		} else {
			return false;
		}
	}

	public boolean supports(Class<?> arg0) {
		return true;
	}

	public int vote(Authentication authentication, Object object,
			Collection<ConfigAttribute> attributes) {
		Calendar calendar = Calendar.getInstance();
		
		int currentHour = calendar.get(Calendar.HOUR_OF_DAY);
		
		if(!isDaylight(currentHour)) {
			return ACCESS_GRANTED;
		}
		
		return ACCESS_DENIED;
	}

	private boolean isDaylight(int currentHour) {
		return currentHour>=SUNRISE_HOUR && currentHour<=SUNSET_HOUR;
	}

}