Make Java an optional dependency

CMakeLists.txt

@@ -21,7 +21,7 @@ project(fdb
   VERSION 6.1.0
   DESCRIPTION "FoundationDB is a scalable, fault-tolerant, ordered key-value store with full ACID transactions."
   HOMEPAGE_URL "http://www.foundationdb.org/"
-  LANGUAGES ASM C CXX Java)
+  LANGUAGES ASM C CXX)
 
 if(WIN32)
   # C# is currently only supported on Windows.
@@ -57,29 +57,16 @@ find_package(PythonLibs 3.4 REQUIRED)
 
 
 ################################################################################
-# LibreSSL
+# Compiler configuration
 ################################################################################
 
-set(DISABLE_TLS OFF CACHE BOOL "Don't try to find LibreSSL and always build without TLS support")
+include(ConfigureCompiler)
-if(DISABLE_TLS)
-  set(WITH_TLS FALSE)
-else()
-  set(LIBRESSL_USE_STATIC_LIBS TRUE)
-  find_package(LibreSSL)
-  if(LibreSSL_FOUND)
-    set(WITH_TLS TRUE)
-  else()
-    message(STATUS "LibreSSL NOT Found - Will compile without TLS Support")
-    message(STATUS "You can set LibreSSL_ROOT to the LibreSSL install directory to help cmake find it")
-    set(WITH_TLS FALSE)
-  endif()
-endif()
 
 ################################################################################
 # Compiler configuration
 ################################################################################
 
-include(ConfigureCompiler)
+include(FDBComponents)
 
 ################################################################################
 # Get repository information
@@ -256,3 +243,9 @@ if (CMAKE_EXPORT_COMPILE_COMMANDS)
 	)
   add_custom_target(procossed_compile_commands ALL DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/compile_commands.json ${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json)
 endif()
+
+################################################################################
+# Inform user which components we are going to build
+################################################################################
+
+print_components()

bindings/CMakeLists.txt

@@ -1,3 +1,5 @@
 add_subdirectory(c)
 add_subdirectory(python)
-add_subdirectory(java)
+if(BUILD_JAVA)
+  add_subdirectory(java)
+endif()

bindings/java/CMakeLists.txt

@@ -1,7 +1,3 @@
-include(UseJava)
-find_package(JNI 1.8 REQUIRED)
-find_package(Java 1.8 COMPONENTS Development REQUIRED)
-
 set(JAVA_BINDING_SRCS
   src/main/com/apple/foundationdb/async/AsyncIterable.java
   src/main/com/apple/foundationdb/async/AsyncIterator.java

cmake/FDBComponents.cmake

@@ -0,0 +1,42 @@
+################################################################################
+# Java Bindings
+################################################################################
+
+set(BUILD_JAVA OFF)
+find_package(JNI 1.8 REQUIRED)
+find_package(Java 1.8 COMPONENTS Development)
+if(JNI_FOUND AND Java_FOUND AND Java_Development_FOUND)
+  set(BUILD_JAVA ON)
+  include(UseJava)
+  enable_language(Java)
+endif()
+
+################################################################################
+# LibreSSL
+################################################################################
+
+set(DISABLE_TLS OFF CACHE BOOL "Don't try to find LibreSSL and always build without TLS support")
+if(DISABLE_TLS)
+  set(WITH_TLS OFF)
+else()
+  set(LIBRESSL_USE_STATIC_LIBS TRUE)
+  find_package(LibreSSL)
+  if(LibreSSL_FOUND)
+    set(WITH_TLS ON)
+  else()
+    message(STATUS "LibreSSL NOT Found - Will compile without TLS Support")
+    message(STATUS "You can set LibreSSL_ROOT to the LibreSSL install directory to help cmake find it")
+    set(WITH_TLS OFF)
+  endif()
+endif()
+
+
+function(print_components)
+  message(STATUS "=============================")
+  message(STATUS "   Components Build Overview ")
+  message(STATUS "=============================")
+  message(STATUS "Build Python Bindings:    ON")
+  message(STATUS "Build Java Bindings:      ${BUILD_JAVA}")
+  message(STATUS "Build with TLS support:   ${WITH_TLS}")
+  message(STATUS "=============================")
+endfunction()