1 /*
2 * Copyright (c) 2005, The K-Wf Grid Consortium
3 * Fraunhofer Institute for Computer Architecture and Software Technology
4 * See http://www.kwfgrid.eu and http://www.first.fraunhofer.de for more details.
5 */
6 package net.kwfgrid.gwes.uiproxy;
7
8 import java.util.*;
9
10 /**
11 A two dimensional HashMap.
12 */
13 public class HashMapOfMaps extends HashMap {
14 public HashMapOfMaps() {
15 super();
16 }
17
18 /**
19 Create a mapping from the specified key to an empty map.
20 If the key already exists this method will do nothing.
21 @return The map the specified key is mapped to.
22 */
23 public synchronized Map createKey(Object key) {
24 Map map = getMap(key);
25 if (map==null) {
26 map = new HashMap();
27 super.put(key, map);
28 }
29 return map;
30 }
31
32 /**
33 Overridden. This method is not allowed for this class and thus does nothing.
34 @return <code>null</code>
35 */
36 public synchronized Object put(Object key, Object value) {
37 return null;
38 }
39
40 /**
41 Create a two dimensional mapping for the specified keys and value.
42 @return The value formerly mapped to the specified keys (maybe <code>null</code>).
43 */
44 public synchronized Object put(Object key1, Object key2, Object value) {
45 Map index2 = createKey(key1);
46 Object old = index2.get(key2);
47 index2.put(key2, value);
48 return old;
49 }
50
51 /**
52 Get the map the specified key is mapped to.
53 @return The map or <code>null</code> if no mapping for the specified key exists.
54 */
55 public synchronized Map getMap(Object key) {
56 return (Map)get(key);
57 }
58
59 /**
60 Get the value for a two dimensional mapping.
61 */
62 public synchronized Object get(Object key1, Object key2) {
63 Map index2 = getMap(key1);
64 if (index2!=null) return index2.get(key2);
65 else return null;
66 }
67
68 /**
69 Remove a two dimensional mapping.
70 @return The value formerly mapped to the specified keys.
71 */
72 public synchronized Object remove(Object key1, Object key2) {
73 Map index2 = getMap(key1);
74 if (index2!=null) return index2.remove(key2);
75 else return null;
76 }
77 }
78