Defined three remoting roles in Jenkins.

(This requires 82211d10bfc7d066121ba80c8a6755d1dae97bf2 in remoting)

core/src/main/java/jenkins/security/Roles.java

+package jenkins.security;
+
+import org.jenkinsci.remoting.Role;
+
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * Predefined {@link Role}s in Jenkins.
+ *
+ * <p>
+ * In Jenkins, there is really only one interesting role, which is the Jenkins master.
+ * Slaves, CLI, and Maven processes are all going to load classes from the master,
+ * which means it accepts anything that the master asks for, and thus they need
+ * not have any role.
+ *
+ * @author Kohsuke Kawaguchi
+ */
+public class Roles {
+    public static final Role MASTER = new Role("master");
+
+    /**
+     * Indicates that a callable runs on masters, requested by slaves/CLI/maven/whatever.
+     */
+    public static final Collection<Role> FOR_MASTER = Collections.singleton(MASTER);
+
+    public static final Role SLAVE = new Role("slave");
+
+    /**
+     * Indicates that a callable is meant to run on slaves.
+     *
+     * This isn't used to reject callables to run on the slave, but rather to allow
+     * the master to promptly reject callables that are really not meant to be run on
+     * the master (as opposed to ones that do not have that information, which gets
+     * {@link Role#UNKNOWN})
+     */
+    public static final Collection<Role> FOR_SLAVE = Collections.singleton(SLAVE);
+}