ob-java.el: Use customizable commands, avoid incompatability

* lisp/ob-java.el: Use customizable variables for java compiler and
runtime commands.  Move variable declarations to fix byte-compile
warnings.  Change Author.  Change tabs to spaces.

A recent patch replaced `defcustom' with `defvar' for variables that
point to the java compiler and runtime commands, which would break
functionality for anyone who had customized the variable.  This
reverts that change.

ob-java is using features not available on older versions of emacs
which org supports.  This replaces them with alternatives.

lisp/ob-java.el

@@ -2,7 +2,9 @@
 
 ;; Copyright (C) 2011-2020 Free Software Foundation, Inc.
 
-;; Author: Ian Martins <ianxm@jhu.edu>
+;; Authors: Eric Schulte
+;;          Dan Davison
+;; Maintainer: Ian Martins <ianxm@jhu.edu>
 ;; Keywords: literate programming, reproducible research
 ;; Homepage: https://orgmode.org
 
@@ -31,32 +33,98 @@
 (defvar org-babel-tangle-lang-exts)
 (add-to-list 'org-babel-tangle-lang-exts '("java" . "java"))
 
+(defvar org-babel-temporary-directory) ; from ob-core
+
 (defvar org-babel-default-header-args:java '()
   "Default header args for java source blocks.")
 
 (defconst org-babel-header-args:java '((imports . :any))
   "Java-specific header arguments.")
 
-(defvar org-babel-java-compiler-command "javac"
-  "Name of the command to execute the java compiler.")
+(defcustom org-babel-java-command "java"
+  "Name of the java command.
+May be either a command in the path, like java or an absolute
+path name, like /usr/local/bin/java.  Parameters may be used,
+like java -verbose."
+  :group 'org-babel
+  :package-version '(Org . "9.5")
+  :type 'string)
 
-(defvar org-babel-java-runtime-command "java"
-  "Name of the command to run the java runtime.")
+(defcustom org-babel-java-compiler "javac"
+  "Name of the java compiler.
+May be either a command in the path, like javac or an absolute
+path name, like /usr/local/bin/javac.  Parameters may be used,
+like javac -verbose."
+  :group 'org-babel
+  :package-version '(Org . "9.5")
+  :type 'string)
 
 (defcustom org-babel-java-hline-to "null"
   "Replace hlines in incoming tables with this when translating to java."
   :group 'org-babel
-  :version "25.2"
-  :package-version '(Org . "9.3")
+  :package-version '(Org . "9.5")
   :type 'string)
 
 (defcustom org-babel-java-null-to 'hline
   "Replace `null' in java tables with this before returning."
   :group 'org-babel
-  :version "25.2"
-  :package-version '(Org . "9.3")
+  :package-version '(Org . "9.5")
   :type 'symbol)
 
+(defconst org-babel-java--package-re "^[[:space:]]*package[[:space:]]+\\\([[:alnum:]_\.]+\\\);$"
+  "Regexp for the package statement.")
+(defconst org-babel-java--imports-re "^[[:space:]]*import[[:space:]]+\\\([[:alnum:]_\.]+\\\);$"
+  "Regexp for import statements.")
+(defconst org-babel-java--class-re "^[[:space:]]*\\\(?:public[[:space:]]+\\\)?class[[:space:]]+\\\([[:alnum:]_]+\\\)[[:space:]]*\n?[[:space:]]*{"
+  "Regexp for the class declaration.")
+(defconst org-babel-java--main-re "public static void main(String\\\(?:\\[]\\\)?[[:space:]]+[^ ]+\\\(?:\\[]\\\)?).*\n?[[:space:]]*{"
+  "Regexp for the main method declaration.")
+(defconst org-babel-java--any-method-re "public .*(.*).*\n?[[:space:]]*{"
+  "Regexp for any method.")
+(defconst org-babel-java--result-wrapper "\n    public static String __toString(Object val) {
+        if (val instanceof String) {
+            return \"\\\"\" + val + \"\\\"\";
+        } else if (val == null) {
+            return \"null\";
+        } else if (val.getClass().isArray()) {
+            StringBuffer sb = new StringBuffer();
+            Object[] vals = (Object[])val;
+            sb.append(\"[\");
+            for (int ii=0; ii<vals.length; ii++) {
+                sb.append(__toString(vals[ii]));
+                if (ii<vals.length-1)
+                    sb.append(\",\");
+            }
+            sb.append(\"]\");
+            return sb.toString();
+        } else if (val instanceof List) {
+            StringBuffer sb = new StringBuffer();
+            List vals = (List)val;
+            sb.append(\"[\");
+            for (int ii=0; ii<vals.size(); ii++) {
+                sb.append(__toString(vals.get(ii)));
+                if (ii<vals.size()-1)
+                    sb.append(\",\");
+            }
+            sb.append(\"]\");
+            return sb.toString();
+        } else {
+            return String.valueOf(val);
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedWriter output = new BufferedWriter(new FileWriter(\"%s\"));
+        output.write(__toString(_main(args)));
+        output.close();
+    }"
+  "Code to inject into a class so that we can capture the value it returns.
+This implementation was inspired by ob-python, although not as
+elegant.  This modified the source block to write out the value
+it wants to return to a temporary file so that ob-java can read
+it back.  The name of the temporary file to write must be
+replaced in this string.")
+
 (defun org-babel-execute:java (body params)
   "Execute a java source block with BODY code and PARAMS params."
   (let* (;; if true, run from babel temp directory
@@ -67,7 +135,7 @@
          ;; just the class name
          (classname (car (last (split-string fullclassname "\\."))))
          ;; just the package name
-         (packagename (if (seq-contains fullclassname ?.)
+         (packagename (if (string-match-p "\\." fullclassname)
                           (file-name-base fullclassname)))
          ;; the base dir that contains the top level package dir
          (basedir (file-name-as-directory (if run-from-temp
@@ -80,19 +148,19 @@
                        basedir))
          ;; the filename of the source file
          (src-file (concat packagedir classname ".java"))
-	 ;; compiler flags
-	 (cmpflag (or (cdr (assq :cmpflag params)) ""))
-	 ;; runtime flags
+         ;; compiler flags
+         (cmpflag (or (cdr (assq :cmpflag params)) ""))
+         ;; runtime flags
          (cmdline (or (cdr (assq :cmdline params)) ""))
          ;; command line args
-	 (cmdargs (or (cdr (assq :cmdargs params)) ""))
+         (cmdargs (or (cdr (assq :cmdargs params)) ""))
          ;; the command to compile and run
-         (cmd (concat org-babel-java-compiler-command " " cmpflag " "
+         (cmd (concat org-babel-java-compiler " " cmpflag " "
                       (org-babel-process-file-name src-file 'noquote)
-                      " && " org-babel-java-runtime-command
+                      " && " org-babel-java-command
                       " -cp " (org-babel-process-file-name basedir 'noquote)
-		      " " cmdline " " (if run-from-temp classname fullclassname)
-		      " " cmdargs))
+                      " " cmdline " " (if run-from-temp classname fullclassname)
+                      " " cmdargs))
          ;; header args for result processing
          (result-type (cdr (assq :result-type params)))
          (result-params (cdr (assq :result-params params)))
@@ -107,7 +175,7 @@
 
     ;; write the source file
     (setq full-body (org-babel-java--expand-for-evaluation
-		     full-body run-from-temp result-type result-file))
+                     full-body run-from-temp result-type result-file))
     (with-temp-file src-file (insert full-body))
 
     ;; compile, run, process result
@@ -134,60 +202,6 @@ return class name.  If that isn't found either, default to Main."
         (and package (concat package ".Main"))
         "Main")))
 
-(defconst org-babel-java--package-re "^[[:space:]]*package[[:space:]]+\\\([[:alnum:]_\.]+\\\);$"
-  "Regexp for the package statement.")
-(defconst org-babel-java--imports-re "^[[:space:]]*import[[:space:]]+\\\([[:alnum:]_\.]+\\\);$"
-  "Regexp for import statements.")
-(defconst org-babel-java--class-re "^[[:space:]]*\\\(?:public[[:space:]]+\\\)?class[[:space:]]+\\\([[:alnum:]_]+\\\)[[:space:]]*\n?[[:space:]]*{"
-  "Regexp for the class declaration.")
-(defconst org-babel-java--main-re "public static void main(String\\\(?:\\[]\\\)?[[:space:]]+[^ ]+\\\(?:\\[]\\\)?).*\n?[[:space:]]*{"
-  "Regexp for the main method declaration.")
-(defconst org-babel-java--any-method-re "public .*(.*).*\n?[[:space:]]*{"
-  "Regexp for any method.")
-(defconst org-babel-java--result-wrapper "\n    public static String __toString(Object val) {
-        if (val instanceof String) {
-            return \"\\\"\" + val + \"\\\"\";
-        } else if (val == null) {
-            return \"null\";
-        } else if (val.getClass().isArray()) {
-            StringBuffer sb = new StringBuffer();
-            Object[] vals = (Object[])val;
-            sb.append(\"[\");
-            for (int ii=0; ii<vals.length; ii++) {
-                sb.append(__toString(vals[ii]));
-                if (ii<vals.length-1)
-                    sb.append(\",\");
-            }
-            sb.append(\"]\");
-            return sb.toString();
-        } else if (val instanceof List) {
-            StringBuffer sb = new StringBuffer();
-            List vals = (List)val;
-            sb.append(\"[\");
-            for (int ii=0; ii<vals.size(); ii++) {
-                sb.append(__toString(vals.get(ii)));
-                if (ii<vals.size()-1)
-                    sb.append(\",\");
-            }
-            sb.append(\"]\");
-            return sb.toString();
-        } else {
-            return String.valueOf(val);
-        }
-    }
-
-    public static void main(String[] args) throws IOException {
-        BufferedWriter output = new BufferedWriter(new FileWriter(\"%s\"));
-        output.write(__toString(_main(args)));
-        output.close();
-    }"
-  "Code to inject into a class so that we can capture the value it returns.
-This implementation was inspired by ob-python, although not as
-elegant.  This modified the source block to write out the value
-it wants to return to a temporary file so that ob-java can read
-it back.  The name of the temporary file to write must be
-replaced in this string.")
-
 (defun org-babel-java--expand-for-evaluation (body suppress-package-p result-type result-file)
   "Expand source block for evaluation.
 In order to return a value we have to add a __toString method.
@@ -209,7 +223,7 @@ RESULT-FILE is the temp file to write the result."
     ;; suppress package statement
     (goto-char (point-min))
     (when (and suppress-package-p
-	       (re-search-forward org-babel-java--package-re nil t))
+               (re-search-forward org-babel-java--package-re nil t))
       (replace-match ""))
 
     ;; add a dummy main method if needed
@@ -225,7 +239,7 @@ RESULT-FILE is the temp file to write the result."
       (goto-char (point-min))
       (org-babel-java--move-past org-babel-java--class-re)
       (insert (format org-babel-java--result-wrapper
-		      (org-babel-process-file-name result-file 'noquote)))
+                      (org-babel-process-file-name result-file 'noquote)))
       (search-forward "public static void main(") ; rename existing main
       (replace-match "public static Object _main("))
 
@@ -263,7 +277,7 @@ is simplest to expand the code block from the inside out."
   (let* ((fullclassname (or (cdr (assq :classname params)) ; class and package
                             (org-babel-java-find-classname body)))
          (classname (car (last (split-string fullclassname "\\.")))) ; just class name
-         (packagename (if (seq-contains fullclassname ?.)  ; just package name
+         (packagename (if (string-match-p "\\." fullclassname)       ; just package name
                           (file-name-base fullclassname)))
          (var-lines (org-babel-variable-assignments:java params))
          (imports-val (assq :imports params))
@@ -405,17 +419,17 @@ Emacs-lisp table, otherwise return the results as a string."
   "Evaluate using an external java process.
 CMD the command to execute.
 
-If RESULT-TYPE equals 'output then return standard output as a
-string.  If RESULT-TYPE equals 'value then return the value
+If RESULT-TYPE equals `output' then return standard output as a
+string.  If RESULT-TYPE equals `value' then return the value
 returned by the source block, as elisp.
 
 RESULT-PARAMS input params used to format the reponse.
 
 RESULT-FILE filename of the tempfile to store the returned value in
-for 'value RESULT-TYPE.  Not used for 'output RESULT-TYPE."
+for `value' RESULT-TYPE.  Not used for `output' RESULT-TYPE."
   (let ((raw (pcase result-type
-               ('output (org-babel-eval cmd ""))
-               ('value (org-babel-eval cmd "")
+               (`output (org-babel-eval cmd ""))
+               (`value (org-babel-eval cmd "")
                        (org-babel-eval-read-file result-file)))))
     (org-babel-result-cond result-params raw
       (org-babel-java-table-or-string raw))))

testing/lisp/test-ob-java.el

@@ -1,7 +1,9 @@
 ;;; test-ob-java.el --- tests for ob-java.el
 
-;; Copyright (c) 2020 Ian Martins
-;; Authors: Ian Martins
+;; Copyright (c) 2020 Free Software Foundation, Inc.
+;; Authors: Eric Schulte
+;;          Dan Davison
+;; Maintainer: Ian Martins <ianxm@jhu.edu>
 
 ;; This file is not part of GNU Emacs.