public static class MainHouseUnit implements RuleUnit {

        private DataSource<Date> now;
        private DataSource<String> part;
        private DataSource<Boolean> switch1;

        public MainHouseUnit() {
            super();
        }

        public DataSource<Date> getNow() {
            return now;
        }

        public DataSource<String> getPart() {
            return part;
        }

        public DataSource<Boolean> getSwitch1() {
            return switch1;
        }

    }

    public static class DayPartUnit implements RuleUnit {

        private DataSource<Date> now;
        private DataSource<Date> aScopedDS;
        private DataSource<String> part;

        public DayPartUnit() {
            super();
        }

        public DataSource<Date> getNow() {
            return now;
        }

        public DataSource<String> getPart() {
            return part;
        }

        public DataSource<Date> getaScopedDS() {
            return aScopedDS;
        }

    }

    public static class SwitchUnit implements RuleUnit {

        private DataSource<String> part;
        private DataSource<Boolean> switch1;

        public SwitchUnit() {
            super();
        }

        public DataSource<String> getPart() {
            return part;
        }

        public DataSource<Boolean> getSwitch1() {
            return switch1;
        }

    }

    private KieBase kieBaseMainGuardSubunitRunBackToMain(boolean currentStyle) {
        // use "hammer" approach with external multiple call to fire, or "drools.run()" approach in rules.
        System.out.println("Running with style: " + currentStyle);
        String drl1 = "package org.drools.compiler.integrationtests\n" +
                      "unit " + getCanonicalSimpleName(MainHouseUnit.class) + "\n" +
                      "import " + DayPartUnit.class.getCanonicalName() + "\n" +
                      "import " + SwitchUnit.class.getCanonicalName() + "\n" +
                      "rule GuardDayPartUnit when\n" +
                      "    Object() from now \n" +
                      "    not( String() from part ) \n" +
                      "then\n" +
                      "    System.out.println(\"Guarding DayPartUnit\");\n" +
                      "    drools.guard(DayPartUnit.class);\n" +
                      "end\n" +
                      "rule GuardSwitchUnit when\n" +
                      "    String() from part \n" +
                      "    not( Boolean() from switch1 ) \n" +
                      "then\n" +
                      "    System.out.println(\"Guarding SwitchUnit\");\n" +
                      "    drools.guard(SwitchUnit.class);\n" +
                      "end\n";

        String drl2 = "package org.drools.compiler.integrationtests\n" +
                      "unit " + getCanonicalSimpleName(DayPartUnit.class) + "\n" +
                      "import " + MainHouseUnit.class.getCanonicalName() + "\n" +
                      "rule doDayPartUnit when\n" +
                      "    $n : Object() from now \n" +
                      "then\n" +
                      "    System.out.println(\"Inside DayPartUnit: \"+$n);\n" +
                      "    part.insert(\"Morning\");\n" +
                      (currentStyle ? "//" : "") + " drools.run(MainHouseUnit.class);\n" +
                      "end\n";

        String drl3 = "package org.drools.compiler.integrationtests\n" +
                      "unit " + getCanonicalSimpleName(SwitchUnit.class) + "\n" +
                      "import " + MainHouseUnit.class.getCanonicalName() + "\n" +
                      "rule doSwitchUnit when\n" +
                      "    $n : String() from part \n" +
                      "then\n" +
                      "    System.out.println(\"Inside SwitchUnit: \"+$n);\n" +
                      "    switch1.insert(true);\n" +
                      (currentStyle ? "//" : "") + " drools.run(MainHouseUnit.class);\n" +
                      "end\n";

        KieBase kbase = new KieHelper().addContent(drl1, ResourceType.DRL)
                                       .addContent(drl2, ResourceType.DRL)
                                       .addContent(drl3, ResourceType.DRL)
                                       .build();

        return kbase;
    }

    @Test
    public void testMainGuardSubunitRunBackToMain_usingHammerStyle() throws Exception {

        KieBase kbase = kieBaseMainGuardSubunitRunBackToMain(true);
        RuleUnitExecutor executor = RuleUnitExecutor.create().bind(kbase);

        executor.newDataSource("now", LocalDateTime.now());
        executor.newDataSource("part");
        executor.newDataSource("aScopedDS");
        DataSource<Boolean> switch1 = executor.newDataSource("switch1");

        RuleUnit adultUnit = new MainHouseUnit();
        executor.run(adultUnit);

        // need a second, "hammer" run.
        executor.run(adultUnit);

        assertEquals(true, switch1.iterator().next());
    }

    @Test
    public void testMainGuardSubunitRunBackToMain_usingRunStyle() throws Exception {

        KieBase kbase = kieBaseMainGuardSubunitRunBackToMain(false);
        RuleUnitExecutor executor = RuleUnitExecutor.create().bind(kbase);

        executor.newDataSource("now", LocalDateTime.now());
        executor.newDataSource("part");
        executor.newDataSource("aScopedDS");
        DataSource<Boolean> switch1 = executor.newDataSource("switch1");

        RuleUnit adultUnit = new MainHouseUnit();
        executor.run(adultUnit); // FAILs with trying to lookup method getaScopedDS() on the MainHouseUnit (which is not correct unit). 

        // does NOT need a second, "hammer" run.

        assertEquals(true, switch1.iterator().next());
    }

    public static class EmptyUnit implements RuleUnit {

        public EmptyUnit() {
            // no-args constructor.
        }
    }

    public static class StringDSUnit implements RuleUnit {

        private DataSource<String> strings;

        public StringDSUnit() {
            // no-args constructor.
        }

        public DataSource<String> getStrings() {
            return strings;
        }

    }

    @Test
    public void testGuardAndRunBack() {
        String drl1 = "package org.drools.compiler.integrationtests\n" +
                      "unit " + getCanonicalSimpleName(EmptyUnit.class) + "\n" +
                      "import " + StringDSUnit.class.getCanonicalName() + "\n" +
                      "rule RGuard when\n" +
                      "then\n" +
                      "    System.out.println(\"Guarding StringDSUnit\");\n" +
                      "    drools.guard(StringDSUnit.class);\n" +
                      "end\n";

        String drl2 = "package org.drools.compiler.integrationtests\n" +
                      "unit " + getCanonicalSimpleName(StringDSUnit.class) + "\n" +
                      "import " + EmptyUnit.class.getCanonicalName() + "\n" +
                      "rule RGoBack when\n" +
                      "then\n" +
                      "    System.out.println(\"Inside StringDSUnit: \");\n" +
                      "    drools.run(EmptyUnit.class);\n" +
                      "end\n";

        KieBase kbase = new KieHelper().addContent(drl1, ResourceType.DRL)
                                       .addContent(drl2, ResourceType.DRL)
                                       .build();
        RuleUnitExecutor executor = RuleUnitExecutor.create().bind(kbase);

        executor.newDataSource("strings", "abc", "xyz");

        RuleUnit adultUnit = new EmptyUnit();
        executor.run(adultUnit); // FAILs with trying to lookup method getStrings() on the EmptyUnit (which is not correct unit). 

    }