Implemented back button (#).

Author: oluwasayo

pom.xml

@@ -5,7 +5,7 @@
 
   <groupId>com.hextremelabs.ussd</groupId>
   <artifactId>lib-ussd</artifactId>
-  <version>1.1-SNAPSHOT</version>
+  <version>1.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <parent>

src/main/java/com/hextremelabs/ussd/rpc/Endpoint.java

@@ -7,6 +7,7 @@
 import com.hextremelabs.ussd.handler.UssdHandler;
 import com.hextremelabs.ussd.internal.Internal;
 import com.hextremelabs.ussd.internal.Internal.Log;
+import com.hextremelabs.ussd.internal.Internal.Pair;
 import com.hextremelabs.ussd.internal.VisibleForTesting;
 import com.hextremelabs.ussd.session.Session;
 import com.hextremelabs.ussd.session.SessionManager;
@@ -91,16 +92,33 @@ String handleRequest(UssdRequest request) {
     List<String> commands = parse(request.getMessage());
     if (session == null) {
       session = new Session(request);
-      session.pushScreen(uiManager.getHomeScreen(), uiManager.render(uiManager.getHomeScreen(), null));
+      session.pushScreen(uiManager.getHomeScreen(), uiManager.render(uiManager.getHomeScreen()));
       if (commands.size() == 1) {
         if (uiManager.getHomeScreen().getType() != DISPLAY) {
           sessionManager.putSession(session);
         }
 
-        return uiManager.render(uiManager.getHomeScreen());
+        return session.peekLastScreen().getValue();
       }
     }
 
+    if (commands.size() == 1 && "#".equals(commands.get(0))) {
+      System.out.println("###: " + session.getNavigation());
+      session.pollLastScreen();
+      final Pair<Screen, String> lastScreen = session.peekLastScreen();
+      if (lastScreen != null) {
+        return lastScreen.getValue();
+      }
+
+      session.pushScreen(uiManager.getHomeScreen(), uiManager.render(uiManager.getHomeScreen()));
+      sessionManager.putSession(session);
+      return session.peekLastScreen().getValue();
+    }
+
+    if (commands.size() > 1) {
+      commands.remove(0);
+    }
+
     String result = null;
     if (commands.isEmpty()) {
       return session.peekLastScreen().getValue();
@@ -172,11 +190,14 @@ private String execute(Session session, String command)
     }
 
     screen = session.peekLastScreen().getKey();
+    session.peekLastScreen().setValue(uiManager.render(screen, executionResult));
     if (screen.getType() == DISPLAY) {
       sessionManager.invalidate(session);
+    } else {
+      sessionManager.putSession(session);
     }
 
-    return uiManager.render(screen, executionResult);
+    return session.peekLastScreen().getValue();
   }
 
   @VisibleForTesting

src/test/java/com/hextremelabs/ussd/rpc/EndpointTest.java

@@ -52,6 +52,12 @@ public void handleRequest() throws Exception {
 
     assertEquals("Welcome~1. Greet Me~2. Exit", endpoint.handleRequest(handler.parseRequest(httpRequest)));
 
+    when(httpRequest.getParameter("message")).thenReturn("1");
+    assertEquals("Lib-USSD~What is your name?", endpoint.handleRequest(handler.parseRequest(httpRequest)));
+
+    when(httpRequest.getParameter("message")).thenReturn("#"); // Back button.
+    assertEquals("Welcome~1. Greet Me~2. Exit", endpoint.handleRequest(handler.parseRequest(httpRequest)));
+
     when(httpRequest.getParameter("message")).thenReturn("1");
     assertEquals("Lib-USSD~What is your name?", endpoint.handleRequest(handler.parseRequest(httpRequest)));
     when(httpRequest.getParameter("message")).thenReturn("Sayo");
@@ -64,7 +70,10 @@ public void handleRequest() throws Exception {
     assertEquals("Goodbye~Sad to see you go", endpoint.handleRequest(handler.parseRequest(httpRequest)));
 
     // Goodbye page with is a DISPLAY page terminates the session.
-    assertEquals("Welcome~1. Greet Me~2. Exit", endpoint.handleRequest(handler.parseRequest(httpRequest)));
+    when(httpRequest.getParameter("message")).thenReturn("*556*2#");
+    assertEquals("Goodbye~Sad to see you go", endpoint.handleRequest(handler.parseRequest(httpRequest)));
+
+
   }
 
   @Test