UseJava.cmake: require explicit request to include jars

Modify add_jar to (partly) use cmake_parse_arguments, and to require
using the named argument list INCLUDE_JARS to specify jar files (or jar
targets) to use as dependencies when creating a jar. This preserves the
ability to have such, while restoring the historic behavior that jar
files listed as sources are ignored. (The code now explicitly ignores
them, however, rather than adding them to an unused local variable, so
that it is more clear that nothing is being done with them.)

Modules/UseJava.cmake

@@ -3,11 +3,19 @@
 # has already been loaded.  See FindJava.cmake for information on how to
 # load Java into your CMake project.
 #
-# add_jar(TARGET_NAME SRC1 SRC2 .. SRCN RCS1 RCS2 .. RCSN)
+# add_jar(target_name
+#         [SOURCES] source1 [source2 ...] [resource1 ...]
+#         [INCLUDE_JARS jar1 [jar2 ...]]
+#        )
 #
-# This command creates a <TARGET_NAME>.jar. It compiles the given source
+# This command creates a <target_name>.jar. It compiles the given source files
-# files (SRC) and adds the given resource files (RCS) to the jar file.
+# (source) and adds the given resource files (resource) to the jar file. If
-# If only resource files are given then just a jar file is created.
+# only resource files are given then just a jar file is created. The list of
+# include jars are added to the classpath when compiling the java sources and
+# also to the dependencies of the target. INCLUDE_JARS also accepts other
+# target names created by add_jar. For backwards compatibility, jar files
+# listed as sources are ignored (as they have been since the first version of
+# this module).
 #
 # Additional instructions:
 #   To add compile flags to the target you can set these flags with
@@ -190,6 +198,8 @@
 # (To distribute this file outside of CMake, substitute the full
 #  License text for the above reference.)
 
+include(${CMAKE_CURRENT_LIST_DIR}/CMakeParseArguments.cmake)
+
 function (__java_copy_file src dest comment)
     add_custom_command(
         OUTPUT  ${dest}
@@ -205,7 +215,10 @@ set(_JAVA_CLASS_FILELIST_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/UseJavaClassFilelist.c
 set(_JAVA_SYMLINK_SCRIPT ${CMAKE_CURRENT_LIST_DIR}/UseJavaSymlinks.cmake)
 
 function(add_jar _TARGET_NAME)
-    set(_JAVA_SOURCE_FILES ${ARGN})
+
+    cmake_parse_arguments(_add_jar "" "" "SOURCES;INCLUDE_JARS" ${ARGN})
+
+    set(_JAVA_SOURCE_FILES ${_add_jar_SOURCES} ${_add_jar_UNPARSED_ARGUMENTS})
 
     if (NOT DEFINED CMAKE_JAVA_TARGET_OUTPUT_DIR)
       set(CMAKE_JAVA_TARGET_OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR})
@@ -265,14 +278,7 @@ function(add_jar _TARGET_NAME)
         get_filename_component(_JAVA_PATH ${_JAVA_SOURCE_FILE} PATH)
         get_filename_component(_JAVA_FULL ${_JAVA_SOURCE_FILE} ABSOLUTE)
 
-        if (TARGET ${_JAVA_SOURCE_FILE})
+        if (_JAVA_EXT MATCHES ".java")
-            get_target_property(_JAVA_JAR_PATH ${_JAVA_SOURCE_FILE} JAR_FILE)
-            set(CMAKE_JAVA_INCLUDE_PATH_FINAL "${CMAKE_JAVA_INCLUDE_PATH_FINAL}${CMAKE_JAVA_INCLUDE_FLAG_SEP}${_JAVA_JAR_PATH}")
-            list(APPEND CMAKE_JAVA_INCLUDE_PATH ${_JAVA_JAR_PATH})
-            list(APPEND _JAVA_DEPENDS ${_JAVA_SOURCE_FILE})
-            list(APPEND _JAVA_COMPILE_DEPENDS ${_JAVA_SOURCE_FILE})
-
-        elseif (_JAVA_EXT MATCHES ".java")
             file(RELATIVE_PATH _JAVA_REL_BINARY_PATH ${CMAKE_JAVA_TARGET_OUTPUT_DIR} ${_JAVA_FULL})
             file(RELATIVE_PATH _JAVA_REL_SOURCE_PATH ${CMAKE_CURRENT_SOURCE_DIR} ${_JAVA_FULL})
             string(LENGTH ${_JAVA_REL_BINARY_PATH} _BIN_LEN)
@@ -292,10 +298,7 @@ function(add_jar _TARGET_NAME)
                 OR _JAVA_EXT MATCHES ".war"
                 OR _JAVA_EXT MATCHES ".ear"
                 OR _JAVA_EXT MATCHES ".sar")
-            set(CMAKE_JAVA_INCLUDE_PATH_FINAL "${CMAKE_JAVA_INCLUDE_PATH_FINAL}${CMAKE_JAVA_INCLUDE_FLAG_SEP}${_JAVA_SOURCE_FILE}")
+            # Ignored for backward compatibility
-            list(APPEND CMAKE_JAVA_INCLUDE_PATH ${_JAVA_SOURCE_FILE})
-            list(APPEND _JAVA_DEPENDS ${_JAVA_SOURCE_FILE})
-            list(APPEND _JAVA_COMPILE_DEPENDS ${_JAVA_SOURCE_FILE})
 
         elseif (_JAVA_EXT STREQUAL "")
             list(APPEND CMAKE_JAVA_INCLUDE_PATH ${JAVA_JAR_TARGET_${_JAVA_SOURCE_FILE}} ${JAVA_JAR_TARGET_${_JAVA_SOURCE_FILE}_CLASSPATH})
@@ -309,6 +312,25 @@ function(add_jar _TARGET_NAME)
         endif ()
     endforeach()
 
+    foreach(_JAVA_INCLUDE_JAR ${_add_jar_INCLUDE_JARS})
+        if (TARGET ${_JAVA_INCLUDE_JAR})
+            get_target_property(_JAVA_JAR_PATH ${_JAVA_INCLUDE_JAR} JAR_FILE)
+            if (_JAVA_JAR_PATH)
+                set(CMAKE_JAVA_INCLUDE_PATH_FINAL "${CMAKE_JAVA_INCLUDE_PATH_FINAL}${CMAKE_JAVA_INCLUDE_FLAG_SEP}${_JAVA_JAR_PATH}")
+                list(APPEND CMAKE_JAVA_INCLUDE_PATH ${_JAVA_JAR_PATH})
+                list(APPEND _JAVA_DEPENDS ${_JAVA_INCLUDE_JAR})
+                list(APPEND _JAVA_COMPILE_DEPENDS ${_JAVA_INCLUDE_JAR})
+            else ()
+                message(SEND_ERROR "add_jar: INCLUDE_JARS target ${_JAVA_INCLUDE_JAR} is not a jar")
+            endif ()
+        else ()
+            set(CMAKE_JAVA_INCLUDE_PATH_FINAL "${CMAKE_JAVA_INCLUDE_PATH_FINAL}${CMAKE_JAVA_INCLUDE_FLAG_SEP}${_JAVA_INCLUDE_JAR}")
+            list(APPEND CMAKE_JAVA_INCLUDE_PATH "${_JAVA_INCLUDE_JAR}")
+            list(APPEND _JAVA_DEPENDS "${_JAVA_INCLUDE_JAR}")
+            list(APPEND _JAVA_COMPILE_DEPENDS "${_JAVA_INCLUDE_JAR}")
+        endif ()
+    endforeach()
+
     # create an empty java_class_filelist
     if (NOT EXISTS ${CMAKE_JAVA_CLASS_OUTPUT_PATH}/java_class_filelist)
         file(WRITE ${CMAKE_JAVA_CLASS_OUTPUT_PATH}/java_class_filelist "")