--- /dev/null
+" Author: Devon Meunier <devon.meunier@gmail.com>
+" Description: checkstyle for Java files
+
+call ale#Set('java_checkstyle_executable', 'checkstyle')
+call ale#Set('java_checkstyle_config', '/google_checks.xml')
+call ale#Set('java_checkstyle_options', '')
+
+function! ale_linters#java#checkstyle#Handle(buffer, lines) abort
+ let l:output = []
+
+ " modern checkstyle versions
+ let l:pattern = '\v\[(WARN|ERROR)\] [a-zA-Z]?:?[^:]+:(\d+):(\d+)?:? (.*) \[(.+)\]'
+
+ for l:match in ale#util#GetMatches(a:lines, l:pattern)
+ call add(l:output, {
+ \ 'type': l:match[1] is? 'WARN' ? 'W' : 'E',
+ \ 'sub_type': 'style',
+ \ 'lnum': l:match[2] + 0,
+ \ 'col': l:match[3] + 0,
+ \ 'text': l:match[4],
+ \ 'code': l:match[5],
+ \})
+ endfor
+
+ if !empty(l:output)
+ return l:output
+ endif
+
+ " old checkstyle versions
+ let l:pattern = '\v(.+):(\d+): ([^:]+): (.+)$'
+
+ for l:match in ale#util#GetMatches(a:lines, l:pattern)
+ call add(l:output, {
+ \ 'type': l:match[3] is? 'warning' ? 'W' : 'E',
+ \ 'sub_type': 'style',
+ \ 'lnum': l:match[2] + 0,
+ \ 'text': l:match[4],
+ \})
+ endfor
+
+ return l:output
+endfunction
+
+function! s:GetConfig(buffer, config) abort
+ if ale#path#IsAbsolute(a:config)
+ return a:config
+ endif
+
+ let s:file = ale#path#FindNearestFile(a:buffer, a:config)
+
+ return !empty(s:file) ? s:file : a:config
+endfunction
+
+function! ale_linters#java#checkstyle#GetCommand(buffer) abort
+ let l:options = ale#Var(a:buffer, 'java_checkstyle_options')
+ let l:config_option = ale#Var(a:buffer, 'java_checkstyle_config')
+ let l:config = l:options !~# '\v(^| )-c ' && !empty(l:config_option)
+ \ ? s:GetConfig(a:buffer, l:config_option)
+ \ : ''
+
+ return '%e'
+ \ . ale#Pad(l:options)
+ \ . (!empty(l:config) ? ' -c ' . ale#Escape(l:config) : '')
+ \ . ' %s'
+endfunction
+
+call ale#linter#Define('java', {
+\ 'name': 'checkstyle',
+\ 'executable': {b -> ale#Var(b, 'java_checkstyle_executable')},
+\ 'command': function('ale_linters#java#checkstyle#GetCommand'),
+\ 'callback': 'ale_linters#java#checkstyle#Handle',
+\ 'lint_file': 1,
+\})