public class ConcreteStrategy0 {
public void doStrategy(SomeType someData) {
   switch( somefunc(someData ) {
    case 0: ConcreteStrategy1.singleton.doStrategy(someData); break;
    case 1: ConcreteStrategy2.singleton.doStrategy(someData); break;
    default: ConcreteStrategy3.singleton.doStrategy(someData); break;
   }
}

new ConcreteStrategy0().doStrategy(someData);

// Inject strategy: Delegate object creation to a factory
new ConcreteStrategy0().doStrategy(StrategyFactory.Create(), someData);

// And update "doStrategy" to,
public void doStrategy(IStrategy strategy, SomeType someData)
{
    strategy.singleton.doStrategy(someData);
}

// OR Let the strategy do stuff instead
StrategyFactory.Create().doStrategy(someData);

<bean id="client" class="...">
  <property name="strategy" ref="dispatcherStartegy"/>
</bean>
<bean id="dispatcherStartegy" class="...">
  <property name="strategies">
    <map>
      <entry key="0" ref="concreteStrategy1"/>
      <entry key="1" ref="concreteStrategy2"/>
    </map>
  </property>
  <property name="fallbackStrategy" ref="concreteStrategy3"/>
</bean>
<bean id="concreteStrategy1" ... />
<bean id="concreteStrategy2" ... />
<bean id="concreteStrategy3" ... />

class Client {
  Strategy strategy;
  public void setStrategey(Strategy strategy {... }
  public void doSomething(...) {
    ...
    strategy.doStrategy(...);
    ...
  }
}

class DispatcherStrategy implements Strategy {
  Map<Integer,Strategy> strategies;
  Strategy fallbackStrategy;
  ... getters, setters ...
  public void doStrategy(...) {
    Strategy s  = strategies.get(keyFromArguments);
    if ( s==null ) {
      s = fallbackStrategy
    }
    s.doStrategy(...)
  }
}