| package freemarker.template; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * Read-only empty map. {@link #remove(Object)}, {@link #clear()} and |
| * {@link #putAll(Map)} with an empty {@link Map} as parameter are supported |
| * operations (and do nothing) since FreeMarker 2.3.20. |
| * |
| * @deprecated Use {@link Collections#EMPTY_MAP} on J2SE 1.3 or later. |
| */ |
| public class EmptyMap implements Map, Cloneable { |
| public static final EmptyMap instance = new EmptyMap(); |
| |
| public void clear() { |
| // no op |
| } |
| |
| public boolean containsKey(Object arg0) { |
| return false; |
| } |
| |
| public boolean containsValue(Object arg0) { |
| return false; |
| } |
| |
| public Set entrySet() { |
| return Collections.EMPTY_SET; |
| } |
| |
| public Object get(Object arg0) { |
| return null; |
| } |
| |
| public boolean isEmpty() { |
| return true; |
| } |
| |
| public Set keySet() { |
| return Collections.EMPTY_SET; |
| } |
| |
| public Object put(Object arg0, Object arg1) { |
| throw new UnsupportedOperationException("This Map is read-only."); |
| } |
| |
| public void putAll(Map arg0) { |
| // Checking for arg0.isEmpty() wouldn't reflect precisely how putAll in |
| // AbstractMap works. |
| if (arg0.entrySet().iterator().hasNext()) { |
| throw new UnsupportedOperationException("This Map is read-only."); |
| } |
| } |
| |
| public Object remove(Object arg0) { |
| return null; |
| } |
| |
| public int size() { |
| return 0; |
| } |
| |
| public Collection values() { |
| return Collections.EMPTY_LIST; |
| } |
| |
| } |