[groovy] Add lsp server support

layers/+lang/groovy/README.org

@@ -8,6 +8,10 @@
 - [[#description][Description]]
   - [[#features][Features:]]
 - [[#install][Install]]
+- [[#configuration][Configuration]]
+  - [[#choosing-a-backend][Choosing a backend]]
+     - [[#company-groovy][Company-groovy]]
+     - [[#lsp][LSP]]
 - [[#key-bindings][Key bindings]]
   - [[#imports][Imports]]
   - [[#repl][REPL]]
@@ -16,15 +20,60 @@
 This layer supports [[http://www.groovy-lang.org/][Groovy]] development in Spacemacs.
 
 ** Features:
-- Basic dabbrev auto-completion with company
+- Auto-completion
+- Syntax-checking
 - Auto-generate imports with [[https://github.com/mbezjak/emacs-groovy-imports][groovy-imports]]
 - Groovy REPL integration
+- Syntax highlighting
 
 * Install
 To use this configuration layer, add it to your =~/.spacemacs=. You will need to
 add =groovy= to the existing =dotspacemacs-configuration-layers= list in this
 file.
 
+* Configuration
+All layer configurations can be done by setting layer variables in your dotfile.
+No custom user config lines are necessary
+
+** Choosing a backend
+This layer provides two alternative backends to choose from.
+
+*** Company-groovy
+This is the default choice if nothing is set and no lsp layer
+is loaded in your dotfile. This mode only provides very
+limited IDE capabilities. Used best if only small scripts
+are edited. To set explicitly set the following in your
+dotfile:
+
+#+BEGIN_SRC emacs-lisp
+  (groovy :variables groovy-backend 'company-groovy)
+#+END_SRC
+
+*** LSP
+For proper IDE support this backend should be used. It is
+based on an external server which will be started automatically
+by emacs, once a groovy file is opened. The keybindings are
+the same for all lsp modes so if you are already familiar with
+one you should be able to work the same in all modes.
+
+To set explicitly do the following in your dotfile:
+
+#+BEGIN_SRC emacs-lisp
+  (groovy :variables
+          groovy-backend 'lsp
+          lsp-jar-path "path/to/groovy/lsp/jar.jar"
+#+END_SRC
+
+For this to work you will also need to obtain
+the latest version of the lsp server from [[https://github.com/prominic/groovy-language-server][here]].
+The path to the server jar must be given in the layer
+variable =lsp-jar-path=.
+
+NOTE: Keybindings for LSP are defined in the
+LSP layer. Also it is advisable to have a look
+at the autocomplete layer for an optimal
+intellisense config for LSP.
+
 * Key bindings
 ** Imports
 

layers/+lang/groovy/config.el

@@ -0,0 +1,20 @@
+;;; config.el --- Groovy layer configuration File for Spacemacs
+;;
+;; Copyright (c) 2012-2020 Sylvain Benner & Contributors
+;;
+;; Author: Maximilian Wolff <smile13241324@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+;; Variables
+
+(defvar groovy-backend nil
+  "The backend to use for IDE features.
+Possible values are `lsp' and `company-groovy'.
+If `nil' then 'company-groovy` is the default backend unless `lsp' layer is used")
+
+(defvar lsp-jar-path "~/groovy-lsp-all.jar"
+  "The path to the lsp jar file")

layers/+lang/groovy/funcs.el

@@ -1,6 +1,6 @@
 ;;; funcs.el --- Groovy functions File for Spacemacs
 ;;
-;; Copyright (c) 2012-2018 Sylvain Benner & Contributors
+;; Copyright (c) 2012-2020 Sylvain Benner & Contributors
 ;;
 ;; Author: Sylvain Benner <sylvain.benner@gmail.com>
 ;; URL: https://github.com/syl20bnr/spacemacs
@@ -9,6 +9,30 @@
 ;;
 ;;; License: GPLv3
 
+(defun spacemacs//groovy-backend ()
+  "Return selected backend."
+  (if groovy-backend
+      groovy-backend
+    (cond
+     ((configuration-layer/layer-used-p 'lsp) 'lsp)
+     (t 'company-groovy))))
+
+(defun spacemacs//groovy-setup-company ()
+  "Conditionally setup company based on backend."
+  (pcase (spacemacs//groovy-backend)
+    ;; Activate lsp company explicitly to activate
+    ;; standard backends as well
+    (`lsp (spacemacs|add-company-backends
+            :backends company-capf
+            :modes groovy-mode))
+    (`company-groovy (spacemacs|add-company-backends)
+                     :modes groovy-mode)))
+
+(defun spacemacs//groovy-setup-backend ()
+  "Conditionally setup groovy backend."
+  (pcase (spacemacs//groovy-backend)
+    (`lsp (lsp))))
+
 
 ;; REPL
 

layers/+lang/groovy/layers.el

@@ -0,0 +1,14 @@
+;;; layers.el --- Groovy Layer layers File for Spacemacs
+;;
+;; Copyright (c) 2012-2020 Sylvain Benner & Contributors
+;;
+;; Author: Maximilian Wolff <smile13241324@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+(when (and (boundp 'groovy-backend)
+           (eq groovy-backend 'lsp))
+  (configuration-layer/declare-layer-dependencies '(lsp)))

layers/+lang/groovy/packages.el

@@ -1,6 +1,6 @@
 ;;; packages.el --- Groovy Layer packages File for Spacemacs
 ;;
-;; Copyright (c) 2012-2018 Sylvain Benner & Contributors
+;; Copyright (c) 2012-2020 Sylvain Benner & Contributors
 ;;
 ;; Author: Sylvain Benner <sylvain.benner@gmail.com>
 ;; URL: https://github.com/syl20bnr/spacemacs
@@ -9,16 +9,18 @@
 ;;
 ;;; License: GPLv3
 
-(setq groovy-packages
-      '(
-        company
-        groovy-imports
-        groovy-mode
-        org
-        ))
+(defconst groovy-packages
+  '(
+    company
+    groovy-imports
+    groovy-mode
+    org))
 
 (defun groovy/post-init-company ()
-  (spacemacs|add-company-backends :modes groovy-mode))
+  (spacemacs//groovy-setup-company))
+
+(defun groovy/post-init-flycheck ()
+  (spacemacs/enable-flycheck 'groovy-mode))
 
 (defun groovy/init-groovy-imports ()
   (use-package groovy-imports
@@ -34,6 +36,7 @@
     :defer t
     :init
     (progn
+      (setq lsp-groovy-server-file lsp-jar-path)
       (spacemacs/declare-prefix-for-mode 'groovy-mode "ms" "REPL")
       (spacemacs/set-leader-keys-for-major-mode 'groovy-mode
         "'"  'run-groovy
@@ -43,7 +46,8 @@
         "sf" 'groovy-send-definition
         "si" 'run-groovy
         "sR" 'spacemacs/groovy-send-region-switch
-        "sr" 'groovy-send-region))))
+        "sr" 'groovy-send-region)
+      (add-hook 'groovy-mode-hook #'spacemacs//groovy-setup-backend))))
 
 (defun groovy/pre-init-org ()
   (spacemacs|use-package-add-hook org