cmake: ENABLE_JAVA_MODULES is a module switch not a simple option

- ENABLE_JAVA_MODULES depends on ENABLE_JAVA and presence of gradle

Signed-off-by: Hofi <[email protected]>

Author: HofiOne

modules/java-modules/CMakeLists.txt

@@ -1,30 +1,36 @@
-if(ENABLE_JAVA)
-  find_package(Gradle 3.4)
-
-  set(GRADLE_WORKDIR ${CMAKE_CURRENT_BINARY_DIR}/.gradle)
-  set(SYSLOG_DEPS_DIR ${PROJECT_BINARY_DIR}/modules/java)
-
-  if(GRADLE_FOUND)
-    OPTION(ENABLE_JAVA_MODULES "Enable Java modules" ON)
-  else()
-    OPTION(ENABLE_JAVA_MODULES "Enable Java modules" OFF)
-  endif()
-
-  set(JAVA_MOD_DST_DIR "${CMAKE_INSTALL_PREFIX}/lib/syslog-ng/java-modules")
-
-  if(ENABLE_JAVA_MODULES)
-    add_custom_target(BuildJavaModules ALL
-      COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} build copyJars
-    )
-    add_dependencies(BuildJavaModules mod-java)
-
-    install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/built-jars/ DESTINATION lib/syslog-ng/java-modules)
-    install(CODE "execute_process(COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} -PjarDestDir=${JAVA_MOD_DST_DIR} copyLog4j)")
-    install(CODE "execute_process(COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} -PjarDestDir=${JAVA_MOD_DST_DIR} copyJestRuntimeDeps)")
-
-    set_directory_properties(PROPERTIES ADDITIONAL_MAKE_CLEAN_FILES ".gradle")
-    set_directory_properties(PROPERTIES ADDITIONAL_MAKE_CLEAN_FILES "built-jars")
-  endif()
-else()
-  OPTION(ENABLE_JAVA_MODULES "Enable Java modules" OFF)
-endif()
+if (ENABLE_JAVA_MODULES AND NOT ENABLE_JAVA)
+  message(FATAL_ERROR "Java based modules enabled, but the required syslog-ng Java plugin is disabled.")
+endif ()
+
+find_package (Gradle 3.4)
+
+if (ENABLE_JAVA_MODULES AND NOT GRADLE_FOUND)
+  message(FATAL_ERROR "Java based modules enabled, but the required gardle dependency is not found.")
+endif ()
+
+set (CAN_ENABLE_JAVA_MODULES OFF)
+if ((GRADLE_FOUND AND ENABLE_JAVA))
+  set (CAN_ENABLE_JAVA_MODULES ON)
+endif ()
+
+module_switch (ENABLE_JAVA_MODULES "Enable Java modules" CAN_ENABLE_JAVA_MODULES)
+
+if (NOT ENABLE_JAVA_MODULES)
+  return ()
+endif ()
+
+set(GRADLE_WORKDIR ${CMAKE_CURRENT_BINARY_DIR}/.gradle)
+set(SYSLOG_DEPS_DIR ${PROJECT_BINARY_DIR}/modules/java)
+set(JAVA_MOD_DST_DIR "${CMAKE_INSTALL_PREFIX}/lib/syslog-ng/java-modules")
+
+add_custom_target(BuildJavaModules ALL
+  COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} build copyJars
+)
+add_dependencies(BuildJavaModules mod-java)
+
+install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/built-jars/ DESTINATION lib/syslog-ng/java-modules)
+install(CODE "execute_process(COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} -PjarDestDir=${JAVA_MOD_DST_DIR} copyLog4j)")
+install(CODE "execute_process(COMMAND ${GRADLE_EXECUTABLE} --project-cache-dir ${GRADLE_WORKDIR} -g ${GRADLE_WORKDIR} -p ${CMAKE_CURRENT_SOURCE_DIR} -PsyslogBuildDir=${CMAKE_CURRENT_BINARY_DIR} -PsyslogDepsDir=${SYSLOG_DEPS_DIR} -PjarDestDir=${JAVA_MOD_DST_DIR} copyJestRuntimeDeps)")
+
+set_directory_properties(PROPERTIES ADDITIONAL_MAKE_CLEAN_FILES ".gradle")
+set_directory_properties(PROPERTIES ADDITIONAL_MAKE_CLEAN_FILES "built-jars")