extensions/assistedinject/src/com/google/inject/assistedinject/Parameter.java
public Object getValue(Injector injector) {
    if (null == provider) {
      synchronized (this) {
        if (null == provider) {
          provider =
              isProvider
                  ? injector.getProvider(getBindingForType(getProvidedType(type)))
                  : injector.getProvider(getPrimaryBindingKey());
        }
      }
    }

    return isProvider ? provider : provider.get();
  }
public Object getValue(Injector injector) {
    if (null == provider) {
      synchronized (this) {
        if (null == provider) {
          provider =
              isProvider
                  ? injector.getProvider(getBindingForType(getProvidedType(type)))
                  : injector.getProvider(getPrimaryBindingKey());
        }
      }
    }

    return isProvider ? provider : provider.get();
  }
Returns the Guice {@link Key} for this parameter.