1 files changed, 43 insertions, 0 deletions
diff --git a/docs/sandbox/common/language/ControlFlow.java b/docs/sandbox/common/language/ControlFlow.java
new file mode 100644
index 000000000..d832259db
--- /dev/null
+++ b/docs/sandbox/common/language/ControlFlow.java
@@ -0,0 +1,43 @@
+
+package language;
+
+public class ControlFlow {
+    public static void main(String[] argList) {
+        Fact.factorial(6);
+    }
+}
+
+class Fact {
+    static int factorial(int i) {
+        if (i < 0) {
+            throw new IllegalArgumentException("negative: " + i);
+        }
+        if (i > 100) {
+            throw new IllegalArgumentException("big: " + i);
+        }
+        return (i == 0 ? 1 : i * factorial(i-1));
+    }
+}
+
+/**
+ * Demonstrate recursive calls.
+ * @author Erik Hilsdale
+ */
+aspect LogFactorial {
+    // START-SAMPLE language-cflowRecursionBasic Pick out latest and original recursive call
+    /** call to factorial, with argument */
+    pointcut f(int i) : call(int Fact.factorial(int)) && args(i);
+
+    /** print most-recent recursive call */
+    before(int i, final int j) : f(i) && cflowbelow(f(j)) { 
+        System.err.println(i + "-" + j);
+    }
+
+    /** print initial/topmost recursive call */
+    before(int i, final int j) : f(i) 
+        && cflowbelow(cflow(f(j)) && !cflowbelow(f(int))) { 
+        System.err.println(i + "@" + j);
+    }
+    // END-SAMPLE language-cflowRecursionBasic
+}
+