1 files changed, 11 insertions, 7 deletions
diff --git a/src/main/java/au/id/zancanaro/javacheck/state/Command.java b/src/main/java/au/id/zancanaro/javacheck/state/Command.java
index afa3957..78df8f1 100644
--- a/src/main/java/au/id/zancanaro/javacheck/state/Command.java
+++ b/src/main/java/au/id/zancanaro/javacheck/state/Command.java
@@ -2,22 +2,26 @@ package au.id.zancanaro.javacheck.state;
 
 import au.id.zancanaro.javacheck.Generator;
 
-public abstract class Command<State,Args,Result> {
-    public Generator<Args> argsGenerator(State state) {
+public abstract class Command<S, A, R> {
+    public Generator<A> argsGenerator(S state) {
         return Generator.pure(null);
     }
 
-    public boolean preCondition(State state, Args args) {
+    public boolean preCondition(S state, A args) {
         return true;
     }
 
-    public abstract Result runCommand(Args args);
+    public abstract R runCommand(S state, A args) throws Throwable;
 
-    public State nextState(State state, Args args, CommandValue<Result> result) {
+    public S nextState(S state, A args, CommandValue<R> result) {
         return state;
     }
 
-    public boolean postCondition(State oldState, State newState, Args args, Result result) {
-        return true;
+    public void postCondition(S oldState, S newState, A args, R result) throws Throwable {
+    }
+
+    @Override
+    public String toString() {
+        return this.getClass().getSimpleName();
     }
 }