nrf24l01: Added callback functionality for Java

Signed-off-by: Andrei Vasiliu <andrei.vasiliu@intel.com>
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/nrf24l01/Callback.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+class Callback
+{
+  public:
+    virtual ~Callback()
+    {
+    }
+    virtual void run()
+    { /* empty, overloaded in Java*/
+    }
+};
+
+
+static void generic_callback (Callback* callback)
+{
+    if (callback == NULL)
+        return;
+    callback->run();
+}
+#endif

src/nrf24l01/javaupm_nrf24l01.i

@@ -1,9 +1,12 @@
 %module javaupm_nrf24l01
 %include "../upm.i"
 
+%feature("director") Callback;
+
 %include "arrays_java.i";
 %apply signed char[] {uint8_t *};
 
+%include "Callback.h"
 %{
     #include "nrf24l01.h"
 %}

src/nrf24l01/nrf24l01.cxx

@@ -148,6 +148,20 @@ NRF24L01::setPayload (uint8_t payload) {
     m_payload = payload;
 }
 
+#ifdef JAVACALLBACK
+void
+NRF24L01::setDataReceivedHandler (Callback *call_obj)
+{
+    callback_obj = call_obj;
+    dataReceivedHandler = &generic_callback;
+}
+#else
+void setDataReceivedHandler (funcPtrVoidVoid handler)
+{
+    dataReceivedHandler = handler;
+}
+#endif
+
 bool
 NRF24L01::dataReady () {
     /* See note in getData() function - just checking RX_DR isn't good enough */
@@ -315,7 +329,11 @@ void
 NRF24L01::pollListener() {
     if (dataReady()) {
         getData (m_rxBuffer);
-        dataRecievedHandler (); /* let know that data arrived */
+#ifdef JAVACALLBACK
+        dataReceivedHandler (callback_obj); /* let know that data arrived */
+#else
+        dataReceivedHandler (); /* let know that data arrived */
+#endif
     }
 }
 

src/nrf24l01/nrf24l01.h

@@ -33,6 +33,10 @@
 #include <mraa/spi.hpp>
 #include <cstring>
 
+#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+#include "Callback.h"
+#endif
+
 /* Memory Map */
 #define CONFIG              0x00
 #define EN_AA               0x01
@@ -138,7 +142,11 @@
 
 namespace upm {
 
+#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+typedef void (* funcPtrVoidVoid) (Callback *);
+#else
 typedef void (* funcPtrVoidVoid) ();
+#endif
 
 typedef enum {
     NRF_250KBPS = 0,
@@ -249,6 +257,21 @@ class NRF24L01 {
          */
         void    setPayload (uint8_t load);
 
+#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+        /**
+         * Sets the handler to be called when data has been
+         * received
+         * @param call_obj Object used for callback - Java
+         */
+        void setDataReceivedHandler (Callback *call_obj);
+#else
+        /**
+         * Sets the handler to be called when data has been
+         * received
+         * @param handler Handler used for callback
+         */
+        void setDataReceivedHandler (funcPtrVoidVoid handler);
+#endif
         /**
          * Checks if the data has arrived
          */
@@ -350,8 +373,13 @@ class NRF24L01 {
         uint8_t     m_txBuffer[MAX_BUFFER]; /**< Transmit buffer */
         uint8_t     m_bleBuffer [32];       /**< BLE buffer */
 
-        funcPtrVoidVoid dataRecievedHandler; /**< Data arrived handler */
     private:
+#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+        /**< Callback object to use for setting the handler from Java */
+        Callback *callback_obj;
+#endif
+        funcPtrVoidVoid dataReceivedHandler; /**< Data arrived handler */
+
         /**
          * Writes bytes to an SPI device
          */
@@ -385,7 +413,7 @@ class NRF24L01 {
 
         uint8_t swapbits (uint8_t a);
 
-        mraa::Spi        m_spi;
+        mraa::Spi               m_spi;
         uint8_t                 m_ce;
         uint8_t                 m_csn;
         uint8_t                 m_channel;
@@ -394,8 +422,8 @@ class NRF24L01 {
         uint8_t                 m_payload;
         uint8_t                 m_localAddress[5];
 
-        mraa::Gpio       m_csnPinCtx;
-        mraa::Gpio       m_cePinCtx;
+        mraa::Gpio              m_csnPinCtx;
+        mraa::Gpio              m_cePinCtx;
 
         std::string             m_name;
 };