java: mraa jni library now dynamically links to libmraa

libmraajava.so was statically linking to mraa object files causing
duplicate mraa platform instances if a UPM Java module was also loaded.

JNI functionality has been moved into src/java/mraajni.c. JVM object is
now set when JVM is loaded; see updates to src/java/mraajava.i.
This was necessary as the JVM object cannot be directly referenced from
mraa as it will not be available when building C/C++ examples.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/CMakeLists.txt

@@ -117,17 +117,6 @@ set (mraa_LIB_GLOB_HEADERS
   ${PROJECT_SOURCE_DIR}/api/mraa.hpp
 )
 
-add_library (mraa ${mraa_LIB_SRCS})
-
-
-target_link_libraries (mraa ${mraa_LIBS})
-
-set_target_properties(
-   mraa
-   PROPERTIES
-   SOVERSION ${mraa_VERSION_MAJOR}
-   VERSION ${mraa_VERSION_STRING}
-)
 install (FILES ${mraa_LIB_GLOB_HEADERS} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 install (DIRECTORY ${PROJECT_SOURCE_DIR}/api/mraa/ DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mraa)
 
@@ -137,7 +126,6 @@ macro (mraa_CREATE_INSTALL_PKGCONFIG generated_file install_location)
 endmacro (mraa_CREATE_INSTALL_PKGCONFIG)
 mraa_create_install_pkgconfig (mraa.pc ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
 
-install(TARGETS mraa DESTINATION ${CMAKE_INSTALL_LIBDIR})
 
 if (DOXYGEN_FOUND)
   set (CMAKE_SWIG_FLAGS -DDOXYGEN=${DOXYGEN_FOUND})
@@ -187,6 +175,15 @@ if (BUILDSWIG)
       add_subdirectory (python)
     endif ()
     if (BUILDSWIGJAVA)
+      FIND_PACKAGE (JNI REQUIRED)
+      include_directories (
+        ${JAVA_INCLUDE_PATH}
+        ${JAVA_INCLUDE_PATH2}
+        ${CMAKE_CURRENT_SOURCE_DIR}/..
+      )
+      set (mraa_LIB_SRCS ${mraa_LIB_SRCS} ${CMAKE_CURRENT_SOURCE_DIR}/java/mraajni.c)
+      set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fpermissive -DJAVACALLBACK")
+      set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DJAVACALLBACK")
       add_subdirectory (java)
     endif ()
     if (BUILDSWIGNODE)
@@ -198,3 +195,13 @@ if (BUILDSWIG)
     endif ()
   endif ()
 endif ()
+
+add_library (mraa ${mraa_LIB_SRCS})
+target_link_libraries (mraa ${mraa_LIBS})
+set_target_properties(
+   mraa
+   PROPERTIES
+   SOVERSION ${mraa_VERSION_MAJOR}
+   VERSION ${mraa_VERSION_STRING}
+)
+install(TARGETS mraa DESTINATION ${CMAKE_INSTALL_LIBDIR})