FooMultiton

FooMultiton.java

import java.util.HashMap;
import java.util.Map;

public class FooMultiton {
    private static final Map<Object, FooMultiton> instances = new HashMap<Object, FooMultiton>();
 
    private FooMultiton() {
        // no explicit implementation
    }
 
    public static synchronized FooMultiton getInstance(Object key) {
 
        // Our "per key" singleton
        FooMultiton instance = instances.get(key);
 
        if (instance == null) {
            // Lazily create instance
            instance = new FooMultiton();
 
            // Add it to map   
            instances.put(key, instance);
        }
 
        return instance;
    }
 
    // other fields and methods ...
}