package games.strategy.engine.data;
import java.io.Serializable;
/**
* Not an interface because we want the perform() method to be protected.
* A Change encapsulates something that can be done to GameData. We use changes so
* that we can serialize and track change to GameData as they occur.
* When a change is performed on a GameData in a game, the change is serialized and sent
* across the network to all the clients. Since all changes to GameData are done through changes
* and all changes are serialized to all clients, all clients should always be in sync.
* A Change can be inverted to create an equal but opposite change.
* Use ChangeFactory to create Changes.
*/
public abstract class Change implements Serializable {
static final long serialVersionUID = -5563487769423328606L;
protected abstract void perform(GameData data);
public abstract Change invert();
public boolean isEmpty() {
return false;
}
}