package org.ggp.base.util.gdl.grammar; import java.io.ObjectStreamException; import java.io.Serializable; @SuppressWarnings("serial") public abstract class Gdl implements Serializable { public abstract boolean isGround(); @Override public abstract String toString(); /** * This method is used by deserialization to ensure that Gdl objects * loaded from an ObjectInputStream or a remote method invocation * are the versions that exist in the GdlPool. */ protected Object readResolve() throws ObjectStreamException { return GdlPool.immerse(this); } }