1 files changed, 47 insertions, 0 deletions
diff --git a/src/main/java/au/id/zancanaro/javacheck/state/CommandValue.java b/src/main/java/au/id/zancanaro/javacheck/state/CommandValue.java
new file mode 100644
index 0000000..8d3f272
--- /dev/null
+++ b/src/main/java/au/id/zancanaro/javacheck/state/CommandValue.java
@@ -0,0 +1,47 @@
+package au.id.zancanaro.javacheck.state;
+
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.function.Supplier;
+
+public class CommandValue<T> {
+    private static Map<Integer, Object> values = null;
+
+    public static <T> T withValues(Map<Integer, Object> newValues, Supplier<T> action) {
+        Map<Integer,Object> oldValues = values;
+        try {
+            values = newValues;
+            return action.get();
+        } finally {
+            values = oldValues;
+        }
+    }
+
+    private final int id;
+
+    public CommandValue(int id) {
+        this.id = id;
+    }
+
+    public boolean isAbstract() {
+        return values == null;
+    }
+
+    @SuppressWarnings("unchecked")
+    public T get() {
+        if (values.containsKey(getId())) {
+            return (T) values.get(getId());
+        } else {
+            throw new NoSuchElementException("Concrete values cannot be supplied prior to being calculated");
+        }
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    @Override
+    public String toString() {
+        return "#{" + id + "}";
+    }
+}