Initial JNI configuration

ChangeLog

@@ -1,5 +1,11 @@
+
+2024-07-12  Vedant Tewari <[email protected]>
 
-2023-02-25  Ron Norman <[email protected]> 
+	* m4/ax_prog_java.m4, m4/ax_jni_include_dir.m4: Added macros for JNI checks
+	* configure.ac: Added support for Java interoperability through JNI, extending GnuCOBOL ability to interact with external Java libraries
+	* NEWS, DEPENDENCIES: Updated to reflect support for JNI
+
+2023-02-25  Ron Norman <[email protected]>
 
 	* configure.ac: Add check for  sys/time.h
 

DEPENDENCIES

@@ -137,6 +137,21 @@ The following libraries ARE required WHEN :
 
     JSON-C is distributed under Expat License.
 
+5) JNI (Java Native Interface) support is used
+
+    BOTH runtime AND development components required.
+
+    Java Development Kit (JDK) 8 or later
+
+    https://openjdk.org/
+
+    The JDK is distributed under various open-source licenses depending
+    on the vendor and version. Common licenses include the GNU General
+    Public License (GPL) and the Oracle Binary Code License Agreement.
+
+    To enable JNI support, ensure that the JDK is installed on your system,
+    and set the appropriate environment variables (e.g., JAVA_HOME) to point
+    to the JDK installation directory.
 
 See HACKING if you wish to hack the GnuCOBOL source or build directly
 from version control as this includes the list of additional tools

DEPENDENCIES.md

@@ -119,3 +119,13 @@ Support for GENERATE JSON is provided by *one* of the following:
 
     JSON-C is distributed under Expat License.
 
+JNI Support
+------------
+
+Support for JNI (Java Native Interface) is provided by:
+
+* [Java Development Kit (JDK)](https://openjdk.java.net/) 8 or later.
+
+    The JDK is distributed under various open-source licenses depending on the vendor and version. Common licenses include the GNU General Public License (GPL) and the Oracle Binary Code License Agreement.
+
+    To enable JNI support, ensure that the JDK is installed on your system, and set the appropriate environment variables (e.g., JAVA_HOME) to point to the JDK installation directory.

NEWS

@@ -20,6 +20,8 @@ NEWS - user visible changes				-*- outline -*-
 
 
 * New GnuCOBOL features
+** Initial support for Java interoperability through JNI (optional dependency JDK): Java Interoperability: Added initial support for calling   
+   Java methods from COBOL programs via the Java Native Interface (JNI). This feature currently supports static Java methods with no parameters, while handling parameters and return values will be introduced in future updates. The system detects missing Java classes and malformed method names and provides proper error handling. COBOL developers can now use ON EXCEPTION and NOT ON EXCEPTION clauses with Java calls. JNI support is an optional feature that requires the Java Development Kit (JDK) to be installed on the system. Use the --with-java configure option to enable it, and ensure that the JAVA_HOME environment variable is set at runtime to locate the JDK. Without JNI, the runtime will function as usual but Java-related COBOL calls (e.g., CALL "Java.<Class>.<Method>") will not be available
 
 ** file handling: added backends for ODBC (so far PostgrSQL, MySQL, SQLite,
    MSSQL) and OCI, along with new directory COB_SCHEMA_DIR containing the

cobc/ChangeLog

@@ -1,4 +1,8 @@
 
+2024-08-14  Nicolas Berthier <[email protected]>
+
+	* cobc.c (cobc_print_info): added note for Java interoperability
+
 2024-08-04  David Declerck <[email protected]>
 
 	Adjustments to merge 2022-12-21:

cobc/cobc.c

@@ -2620,6 +2620,12 @@ cobc_print_info (void)
 
 	cobc_var_print (_("JSON library"),		_(WITH_JSON), 0);
 
+#ifdef WITH_JNI
+	cobc_var_print (_("Java interoperability"),	_("enabled"), 0);
+#else
+	cobc_var_print (_("Java interoperability"),	_("disabled"), 0);
+#endif
+
 #ifdef COB_DEBUG_LOG
 	cobc_var_print ("DEBUG_LOG",		_("enabled"), 0);
 #endif

cobc/codegen.c

@@ -1,7 +1,7 @@
 /*
    Copyright (C) 2003-2024 Free Software Foundation, Inc.
    Written by Keisuke Nishida, Roger While, Ron Norman, Simon Sobisch,
-   Edward Hart
+   Edward Hart, Vedant Tewari
 
    This file is part of GnuCOBOL.
 
@@ -147,6 +147,7 @@ static struct literal_list	*literal_cache = NULL;
 static struct field_list	*field_cache = NULL;
 static struct field_list	*local_field_cache = NULL;
 static struct call_list		*call_cache = NULL;
+static struct call_list		*call_java_cache = NULL;
 static struct call_list		*func_call_cache = NULL;
 static struct static_call_list	*static_call_cache = NULL;
 static struct base_list		*base_cache = NULL;
@@ -395,6 +396,22 @@ lookup_source (const char *p)
 	return source_id++;
 }
 
+static void
+lookup_java_call(const char *p)
+{
+	struct call_list *clp;
+
+	for (clp = call_java_cache; clp; clp = clp->next) {
+		if (strcmp (p, clp->call_name) == 0) {
+			return;
+		}
+	}
+	clp = cobc_parse_malloc (sizeof (struct call_list));
+	clp->call_name = p;
+	clp->next = call_java_cache;
+	call_java_cache = clp;
+}
+
 static void
 lookup_call (const char *p)
 {
@@ -1978,6 +1995,11 @@ output_call_cache (void)
 		output_local ("static cob_call_union\tcall_%s;\n",
 			      call->call_name);
 	}
+	call_java_cache = call_list_reverse (call_java_cache);
+	for (call = call_java_cache; call; call = call->next) {
+		output_local ("static cob_java_handle*\tcall_java_%s;\n",
+			      call->call_name);
+	}
 	func_call_cache = call_list_reverse (func_call_cache);
 	for (call = func_call_cache; call; call = call->next) {
 		output_local ("static cob_call_union\tfunc_%s;\n",
@@ -7068,6 +7090,69 @@ output_field_constant (cb_tree x, int n, const char *flagname)
 	output_newline ();
 }
 
+static void
+output_exception_handling(struct cb_call *p)
+{
+    if (p->stmt1) {
+        output_line("cob_glob_ptr->cob_stmt_exception = 1;");
+        output_line("COB_RESET_EXCEPTION(0);");
+    } else {
+        output_line("cob_glob_ptr->cob_stmt_exception = 0;");
+    }
+
+    output_line("if ((cob_glob_ptr->cob_exception_code & 0xff00) != 0) {");
+    output_block_open();
+
+    if (p->stmt1) {
+        output_stmt(p->stmt1);  
+    } else if (p->stmt2) {
+        output_stmt(p->stmt2);
+	}
+    output_block_close();
+    output_line("COB_RESET_EXCEPTION(0);");
+}
+
+static void
+output_java_call (struct cb_call *p)
+{
+	if (p->args != NULL || p->call_returning != NULL) {
+    	CB_PENDING ("Java method call with parameters or return values");
+    	COBC_ABORT ();
+	}
+	char* full_name = (char *)CB_LITERAL(p->name)->data; /* Assume java.prefix (enforced in `parser.y`, rule `call_body`)*/
+	char* class_and_method_name = full_name + 5;
+	char *last_dot;
+	char *method_name;
+	const char *class_name;
+	char* mangled;
+	size_t i;
+
+	mangled = strdup(class_and_method_name);
+	for (i = 0; i < strlen(mangled) + 1; i++) {
+		mangled[i] = (mangled[i] == '.') ? '_' : mangled[i];
+	}
+
+	lookup_java_call(mangled);
+
+	last_dot = strrchr(class_and_method_name, '.');
+
+	*last_dot = '\0';
+	method_name = last_dot + 1;
+	class_name = class_and_method_name;
+
+	output_line("if (call_java_%s == NULL)", mangled);
+	output_block_open();
+
+	output_line("call_java_%s = cob_resolve_java(\"%s\", \"%s\", \"()V\");", mangled, class_name, method_name);
+	output_line("cob_call_java(call_java_%s);\n", mangled);
+	output_newline();
+	output_block_close();
+	output_exception_handling(p);
+
+	cobc_free((char*) mangled);
+
+}
+
 static void
 output_call (struct cb_call *p)
 {
@@ -7097,6 +7182,12 @@ output_call (struct cb_call *p)
 	}
 	system_call = NULL;
 
+	if (p->convention & CB_CONV_JAVA) {
+		output_java_call(p);
+		output_exception_handling(p);
+		return;
+	}
+
 #ifdef	_WIN32
 	if (p->convention & CB_CONV_STDCALL) {
 		convention = "_std";

cobc/parser.y

@@ -12253,6 +12253,10 @@ call_body:
 
 	/* Check parameter conformance, if we can work out what is being called. */
 	if (CB_LITERAL_P ($3)) {
+		/* Check for "Java." prefix and set call convention */
+		if (strncasecmp("Java.", (char *)CB_LITERAL ($3)->data, 5) == 0) {
+			call_conv = CB_CONV_JAVA;
+		}
 		cb_check_conformance ($3, $7, $8);
 	} else if (CB_REFERENCE_P ($3)) {
 		cb_tree	ref = cb_ref ($3);

cobc/tree.h

@@ -199,6 +199,7 @@ enum cb_tag {
 #define CB_CONV_THUNK_16	(1 << 5)
 #define CB_CONV_STDCALL		(1 << 6)
 #define CB_CONV_COBOL	(1 << 15)
+#define CB_CONV_JAVA    (1 << 16)
 #define CB_CONV_C	(0)
 #define CB_CONV_PASCAL	(CB_CONV_L_TO_R | CB_CONV_CALLEE_STACK)
 

configure.ac

@@ -113,6 +113,8 @@ AH_TEMPLATE([WITH_JSON], [JSON handler])
 AH_TEMPLATE([WITH_CJSON], [Use cJSON library/source as JSON handler])
 AH_TEMPLATE([WITH_JSON_C], [Use JSON-C library as JSON handler])
 
+AH_TEMPLATE([WITH_JNI], [Support for Java calls through JNI])
+
 AH_TEMPLATE([COB_EXPORT_DYN], [Compile/link option for exporting symbols])
 AH_TEMPLATE([COB_PIC_FLAGS], [Compile/link option for PIC code])
 AH_TEMPLATE([COB_DEBUG_FLAGS], [Compile/link option for debugging])
@@ -483,7 +485,6 @@ AC_CHECK_HEADERS([sys/types.h signal.h stddef.h], [],
 # optional:
 AC_CHECK_HEADERS([sys/time.h locale.h fcntl.h dlfcn.h sys/wait.h sys/sysmacros.h])
 
-
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
 AC_C_BIGENDIAN
@@ -933,7 +934,73 @@ AS_IF([test "$with_xml2" = "yes" -o "$with_xml2" = "check"], [
 	LIBS="$curr_libs"; CPPFLAGS="$curr_cppflags"
 ])
 
+# Check for JNI
+AC_ARG_WITH([java],
+	    [AS_HELP_STRING([--without-java],
+			    [disable Java Interoperability])])
+cob_has_jni=no
+AS_IF([test "x$with_java" != "xno"], [
+	dnl Find `java` and $JAVA_HOME (we need the latter to locate libjvm).
+	dnl AX_CHECK_JAVA_HOME dnl (<- does not appear to work properly)
+	AX_PROG_JAVA
+	if test "x$JAVA_HOME" = x; then
+		JAVA_HOME="$( $JAVA -XshowSettings:properties -version 2>&1 >/dev/null | \
+			      $SED -e '/^[ ]*java.home/!d' -e 's/.*=[ ]*//' )"
+		AC_MSG_NOTICE([Found Java home: ${JAVA_HOME}])
+	else
+		AC_MSG_NOTICE([Given Java home: ${JAVA_HOME}])
+	fi
 
+	dnl Note: AX_PROG_JAVAC might find a `javac` binary that does
+	dnl not match the version of `$JAVA` found above, so we set
+	dnl its path manually.
+	JAVAC="$JAVA_HOME/bin/javac"
+	AX_PROG_JAVAC_WORKS
+
+	AX_JNI_INCLUDE_DIR
+	AS_IF([test "$JNI_INCLUDE_DIRS" != ""], [
+		for JNI_INCLUDE_DIR in $JNI_INCLUDE_DIRS; do
+		    JNI_CPPFLAGS="$JNI_CPPFLAGS -I$JNI_INCLUDE_DIR"
+		done
+		for _dir in "${JAVA_HOME}/jre/lib" "${JAVA_HOME}/lib"; do
+		    if test -d "$_dir"; then
+			JNI_LIBS="$JNI_LIBS -L$_dir"
+		    fi
+		    if test -d "$_dir/server"; then
+			JNI_LIBS="$JNI_LIBS -L$_dir/server"
+		    fi
+		    if test -d "$_dir/client"; then
+			JNI_LIBS="$JNI_LIBS -L$_dir/client"
+		    fi
+		done
+		curr_LIBS="$LIBS"
+		curr_CPPFLAGS="$CPPFLAGS"
+		LIBS="$LIBS $JNI_LIBS -ljvm"
+		CPPFLAGS="$CPPFLAGS $JNI_CPPFLAGS"
+		AC_MSG_CHECKING([if -ljvm brings JNI symbols])
+		AC_LINK_IFELSE([
+		  AC_LANG_SOURCE([[
+		    #include <jni.h>
+		    void main (void) {
+		       (void) JNI_CreateJavaVM (NULL, NULL, NULL);
+		    }
+		  ]])
+		], [
+		        AC_MSG_RESULT([yes])
+			AC_DEFINE([WITH_JNI], [1])
+			JNI_LDFLAGS="$JNI_LIBS"
+			JNI_LIBS="-ljvm"
+			cob_has_jni=yes
+		], [
+		        AC_MSG_RESULT([no])
+		])
+		LIBS="$curr_LIBS"
+		CPPFLAGS="$curr_CPPFLAGS"
+	])
+])
+AS_IF([test "x$with_java" = "xyes" -a "x$cob_has_jni" != "xyes"], [
+	AC_MSG_ERROR([Java interoperability requested, but JNI was not found])
+])
 
 # Checks for cjson/json-c.
 AC_MSG_NOTICE([Checks for JSON handler])
@@ -2570,6 +2637,8 @@ AM_CONDITIONAL([COB_MAKE_LMDB_LIB], [test "$cob_gen_lmdb" = "yes"])
 
 AM_CONDITIONAL([LOCAL_CJSON],[test "$USE_JSON" = "local"])
 
+AM_CONDITIONAL([COB_HAS_JNI], [test "$cob_has_jni" = "yes"])
+
 unset COB_USES_GCC
 unset COB_USES_GCC_NO_ICC
 unset COB_USES_ICC_ONLY
@@ -2660,6 +2729,11 @@ AC_SUBST([OCI_CFLAGS])
 AC_SUBST([BDB_CFLAGS])
 AC_SUBST([LMDB_CFLAGS])
 
+AC_SUBST([JAVAC])
+AC_SUBST([JNI_LIBS])
+AC_SUBST([JNI_LDFLAGS])
+AC_SUBST([JNI_CPPFLAGS])
+
 dnl was used in bin/Makefile.am - seems not to be needed
 dnl AC_SUBST([COB_EXPORT_DYN])
 
@@ -2683,6 +2757,7 @@ AC_SUBST([COB_HAS_OCEXTFH])
 AC_SUBST([COB_HAS_CURSES])
 AC_SUBST([COB_HAS_XML2])
 AC_SUBST([COB_HAS_JSON])
+AC_SUBST([COB_HAS_JNI])
 AC_SUBST([COB_HAS_64_BIT_POINTER])
 AC_SUBST([COB_PATCH_LEVEL], [$with_patch_level]) # needed for bin/cob-config
 
@@ -2804,4 +2879,6 @@ case "$USE_JSON" in
 	;;
 esac
 
+AC_MSG_NOTICE([ Build with Java interoperability:            ${cob_has_jni}])
+
 unset DEFINE_DL