JENKINS-33925 Sample realization of the cps invoker interceptor

lib/src/main/java/com/cloudbees/groovy/cps/sandbox/DefaultInvoker.java

@@ -14,8 +14,8 @@
  *
  * @author Kohsuke Kawaguchi
  */
-public class DefaultInvoker implements Invoker {
-    public Object methodCall(Object receiver, String method, Object[] args) throws Throwable {
+public class DefaultInvoker extends InvokerInterceptor {
+    public Object doMethodCall(Object receiver, String method, Object[] args) throws Throwable {
         CallSite callSite = fakeCallSite(method);
         Object v = callSite.call(receiver,args);
         return v;

lib/src/main/java/com/cloudbees/groovy/cps/sandbox/InvokerInterceptor.java

@@ -0,0 +1,16 @@
+package com.cloudbees.groovy.cps.sandbox;
+
+/**
+ * Allows to override one class to perform real-life tests of the CPS logic
+ *
+ * @author Sergei Parshev <sergei@parshev.net>
+ */
+public abstract class InvokerInterceptor implements Invoker {
+    public Object methodCall(Object receiver, String method, Object[] args) throws Throwable {
+        return doMethodCall(receiver, method, args);
+    }
+
+    abstract Object doMethodCall(Object receiver, String method, Object[] args) throws Throwable;
+
+    private static final long serialVersionUID = 1L;
+}

lib/src/main/java/com/cloudbees/groovy/cps/sandbox/SandboxInvoker.java

@@ -12,8 +12,8 @@
  *
  * @author Kohsuke Kawaguchi
  */
-public class SandboxInvoker implements Invoker {
-    public Object methodCall(Object receiver, String method, Object[] args) throws Throwable {
+public class SandboxInvoker extends InvokerInterceptor {
+    public Object doMethodCall(Object receiver, String method, Object[] args) throws Throwable {
         return Checker.checkedCall(receiver,false,false,method,args);
     }