Our current protocol is something like this :
struct WP_Protocol {
uint8_t appId,
uint16_t originAddr,
uint16_t destAddr,
uint32_t timestamp,
uint16_t sensor1,
uint16_t sensor2,
uint16_t sensor3
}

In our previous code, we pack the data inside single function :
void pack(destAddress,sensor1Data, sensor2Data, sensor3Data) {
struct WP_Protocol packedData;

packedData.appId = AGROMONITORING_APP_ID;
packedData.originAddr = getLocalAddr();
packedData.destAddr = destAddress;
packedData.timestamp = time();
packedData.sensor1 = sensor1Data;
packedData.sensor2 = sensor2Data;
packedData.sensor3 = sensor3Data;

// Send to radio
…
}

It’s good and works well. But suppose we want to change the protocol, we will have to modify the structure and the pack(), and test it again (for big-endian / little-endian sequence, etc). So, the pack() will not be re-usable, because each protocol will have their own pack().

I found better idea. Rather than messing around with pack(), with this method (called decorator design pattern), we can have re-usable codes, multiple-protocols, and minimum testing.

Here’s how :
1) Define the layers
struct sensors {
uint16_t sensor1,
uint16_t sensor2,
uint16_t sensor3
}

struct timestampLayer {
uint32_t timestamp,
void * data
}

struct appIDLayer {
uint8_t appId,
void * data
}

struct addressesLayer {
uint16_t originAddr,
uint16_t destAddr,
void * data
}

2) Define the methods to handle the layers
struct sensor packSensor(sensor1Data, sensor2Data, sensor3Data)
{
struct sensors retVal;

retVal.sensor1 = sensor1Data;
retVal.sensor2 = sensor2Data;
retVal.sensor3 = sensor3Data;

return retVal;
}

struct timestampLayer packTimeStamp(void * data)
{
struct timestampLayer retVal;

retVal.timestamp = time();
retVal.data = data;
return retVal;
}

struct appIDLayer packAppId(void * data)
{
struct appIDLayer retVal;
retVal.appId = AGROMONITORING_APP_ID;
retVal.data = data;
return retVal;
}

struct addressesLayer packAddresses(uint16_t destAddr, void * data)
{
struct addressesLayer retVal;

retVal.originAddr = getLocalId();
retVal.destAddr = destAddr;
retVal.data = data;
return retVal;
}

3) To create old structure, just chain the whole functions :
sendToRadio(
packAppId(
packAddresses(0,
packTimeStamp(
packSensor(sensor1Data, sensor2Data, sensor3Data)))));

To create new protocol, where address layer come first before appId (for example) :
sendToRadio(
packAddresses(0,
packAppId(
packTimeStamp(
packSensor(sensor1Data, sensor2Data, sensor3Data)))));

To create new protocol, where new layer added between timestamp and sensors (for example) :
sendToRadio(
packAddresses(0,
packAppId(
packTimeStamp(
newLayer(
packSensor(sensor1Data, sensor2Data, sensor3Data))))));

Anything that you want to change, just change the chain of calling. Because every layer’s function has been tested before, changing sequence won’t need new testing. The only thing that we need to test is new layer that will be inserted.

In summary, decorator pattern will save testing time, faster to deploy, and minimalize bug.

Joel’s “Fire and Motion” is a good explanation of not feeling guilty =)

Get realistic kid. You’re programmer, and your job is : <gosh!!> reading the source codes !!

Most of us never really really write codes (not from the scratch, I mean). We’re just read someone else’s source code, and fix it when necessary. That’s how the world run, unless you’re God and have remote control to stop the world..

Hey, no kidding here. You’ve only have 24 hours a day. You’ll need at least 5 hours to sleep, 11 hours for yourself, your family, and your social life, and the rest 8 hours for debugging (hmm…where should I put extra 1 hour for coding ??)..

So, instead of adding comments inside your source code, why not coding your codes into self-comment codes..Something like this :

public void updateSprite(long elapsedTime)
{
   float spritePositionX = spriteSpeedX * elapsedTime;
   float spritePositionY = spriteSpeedY * elapsedTime;
   drawSprite(spriteImage, spritePositionX, spritePositionY);
}

There..no need special comments to understand my code right ??

A bit old and stupid applet (hey..I’m new in Java..having animation applet is huge step for me).

Refer to this link to get the demo and the source code.

Download the source code from here

Testing condition:

• Resistance that is used to measure: 23.4 Ohm
• The radio is set to send the data each 1 second.
• The radio is turned off for 1 second

Firmware that is used:

Makefile :
COMPONENT=EasyCollectionAppC
CFLAGS += -I$(TOSDIR)/lib/net \
-I$(TOSDIR)/lib/net/le \
-I$(TOSDIR)/lib/net/ctp \
-DACK_LOW_POWER_LISTENING \
-DCC2420_DEF_CHANNEL=15
include $(MAKERULES)
/////////////////////////////////////////////////////
#include <Timer.h>
module EasyCollectionC {
uses interface Boot;
uses interface SplitControl as RadioControl;
uses interface StdControl as RoutingControl;
uses interface Send;
uses interface Leds;
uses interface Timer<TMilli>;
uses interface RootControl;
uses interface Receive;
uses interface LowPowerListening;
provides interface McuPowerOverride;
}
implementation {
message_t packet;
bool sendBusy = FALSE;


    typedef nx_struct EasyCollectionMsg {
nx_uint16_t data;
} EasyCollectionMsg;


    event void Boot.booted() {
call LowPowerListening.setLocalSleepInterval(1024);
call RadioControl.start();
}


    event void RadioControl.startDone(error_t err) {
if (err != SUCCESS)
call RadioControl.start();
else {
call RoutingControl.start();
if (TOS_NODE_ID == 0) {
call RootControl.setRoot();
}
else {
call Timer.startPeriodic(1024);
}
}
}

    event void RadioControl.stopDone(error_t err) {}

    void sendMessage() {
EasyCollectionMsg* msg = (EasyCollectionMsg*)call Send.getPayload(&packet);
msg->data = 0xAAAA;
if (call Send.send(&packet, sizeof(EasyCollectionMsg)) != SUCCESS)
call Leds.led0On();
else
sendBusy = TRUE;
}


    event void Timer.fired() {
//call Leds.led2Toggle();
if (!sendBusy)
sendMessage();
}


    event void Send.sendDone(message_t* m, error_t err) {
if (err != SUCCESS)
call Leds.led0On();
sendBusy = FALSE;
}


    event message_t*
Receive.receive(message_t* msg, void* payload, uint8_t len) {
//call Leds.led1Toggle();
return msg;
}


    async command mcu_power_t McuPowerOverride.lowestState() {
return ATM128_POWER_DOWN;
}
}
///////////////////////////////////////////////////////////////
configuration EasyCollectionAppC {}
implementation {
components EasyCollectionC, MainC, LedsC, ActiveMessageC;
components CollectionC as Collector;
components new CollectionSenderC(0xee);
components new TimerMilliC();
EasyCollectionC.Boot -> MainC;
EasyCollectionC.RadioControl -> ActiveMessageC;
EasyCollectionC.RoutingControl -> Collector;
EasyCollectionC.Leds -> LedsC;
EasyCollectionC.Timer -> TimerMilliC;
EasyCollectionC.Send -> CollectionSenderC;
EasyCollectionC.RootControl -> Collector;
EasyCollectionC.Receive -> Collector.Receive[0xee];


    components McuSleepC;
McuSleepC.McuPowerOverride -> EasyCollectionC;


    components CC2420ActiveMessageC;
EasyCollectionC.LowPowerListening -> CC2420ActiveMessageC;
}


Sekarang, dengan buku baru gw “Developing Games in Java” – Brackeen, David, gw pindah ngerjain games di Java..Hehehehe…

Alasan gw pake java :

1. Jalan di Windows dan Linux
2. Ga perlu ribet dengan library ini itu..Cukup install JRE, semua beres
3. Instalasinya gampang..(semoga si..blom pernah nyobain)

Yah begitulah pengamatan sementara gw.

I hope this may help my country to develop it’s own games.

Gimana ga gelap coba..dari kemarin ngurus working permit, baru dapat tahap I-nya MSC(Malaysia Multimedia Super Corridor)..Sekarang lg ngurus tahap II-nya MSC..baru setelah itu bisa dapat full working permit..

Soal kenapa gamenya blom dilanjutin, itu karena gw baru pindah ke SUSE Linux Enterprise Desktop 10. Distro itu ga ada eclipse dan CDT-nya, karena itu gw terpaksa nulis program pake vim (kacau dah Novell)..dan karena itulah kerja gw jadi lambaaaat bgt..