Associating a Value with an Object
This example demonstrates how to associate a value with an arbitrary
object. The technique involves saving the object and the associated
value as a key/value pair in an IdentityHashMap. A HashMap
cannot be used for this purpose since if two objects happen to equal
via the Object.equals() method, one of the objects will not be
stored.
// Create the map
Map objMap = new IdentityHashMap();
// Add the object and value pair to the map
Object o1 = new Integer(123);
Object o2 = new Integer(123);
objMap.put(o1, "first");
objMap.put(o2, "second");
// Retrieve the value associated with the objects
Object v1 = objMap.get(o1); // first
Object v2 = objMap.get(o2); // second
This is the most simple and to the point explanation I came across for IdentityHashMap on the net!!!
Kudos for the simplicity and conciseness!