Add support for javalsp configuration options.

This MR adds a new configuration variable `g:ale_java_javalsp_config`
that allows to configure external dependencies and class paths to the
language server.

The variable accepts a dictionary similar to the one supported by the
[vscode/settings.json](https://github.com/georgewfraser/java-language-server#settings)
file.

Deprecates: #2561

1 files changed, 14 insertions, 0 deletions

diff --git a/ale_linters/java/javalsp.vim b/ale_linters/java/javalsp.vim
index f56675d6..baf584c8 100644
--- a/ale_linters/java/javalsp.vim
+++ b/ale_linters/java/javalsp.vim
@@ -2,11 +2,24 @@
 " Description: Support for the Java language server https://github.com/georgewfraser/vscode-javac
 
 call ale#Set('java_javalsp_executable', '')
+call ale#Set('java_javalsp_config', {})
 
 function! ale_linters#java#javalsp#Executable(buffer) abort
     return ale#Var(a:buffer, 'java_javalsp_executable')
 endfunction
 
+function! ale_linters#java#javalsp#Config(buffer) abort
+    let l:defaults = { 'java': { 'classPath': [], 'externalDependencies': [] } }
+    let l:config = ale#Var(a:buffer, 'java_javalsp_config')
+
+    " Ensure the config dictionary contains both classPath and
+    " externalDependencies keys to avoid a NPE crash on Java Language Server.
+    call extend(l:config, l:defaults, 'keep')
+    call extend(l:config['java'], l:defaults['java'], 'keep')
+
+    return l:config
+endfunction
+
 function! ale_linters#java#javalsp#Command(buffer) abort
     let l:executable = ale_linters#java#javalsp#Executable(a:buffer)
 
@@ -38,4 +51,5 @@ call ale#linter#Define('java', {
 \   'command': function('ale_linters#java#javalsp#Command'),
 \   'language': 'java',
 \   'project_root': function('ale#java#FindProjectRoot'),
+\   'lsp_config': function('ale_linters#java#javalsp#Config')
 \})