JavaPMDBear: Detect appropriate linter executable

Describe current executable requirements of pmd or run.sh.

Also remove explicit invocation using `bash`, which was
ineffective as which('run.sh') would only be successful
if the script was executable.

Also add `-f text` arguments, which are mandatory on recent
versions of pmd, but were optional on older supported versions.

Fixes coala#2908

bear-metadata.yaml

@@ -1209,14 +1209,15 @@ bear_metadata:
     filename: JavaPMDBear.py
     requirements:
       exe:
-        bash:
+        pmd:
+        run.sh:
     languages:
       - Java
     tags:
-      - bash
       - exe
       - java
       - pmd
+      - run.sh
   Jinja2Bear:
     name: Jinja2Bear
     subdir: jinja2

bears/java/JavaPMDBear.py

@@ -1,11 +1,17 @@
 from shutil import which
+from dependency_management.requirements.AnyOneOfRequirements import (
+    AnyOneOfRequirements)
+from dependency_management.requirements.ExecutableRequirement import (
+    ExecutableRequirement)
 
 from coalib.bearlib.abstractions.Linter import linter
 from coalib.bearlib import deprecate_settings
 from coala_utils.param_conversion import negate
 
+_executable = which('run.sh') or which('pmd')
 
-@linter('bash', output_format='regex',
+
+@linter(_executable or 'pmd', output_format='regex',
         output_regex=r'.+:(?P<line>.+):(?P<message>.*)')
 class JavaPMDBear:
     """
@@ -17,22 +23,19 @@ class JavaPMDBear:
     """
 
     LANGUAGES = {'Java'}
+    REQUIREMENTS = {
+        AnyOneOfRequirements(
+            [ExecutableRequirement('pmd'),
+             ExecutableRequirement('run.sh'),
+             ]
+        ),
+    }
     AUTHORS = {'The coala developers'}
     AUTHORS_EMAILS = {'[email protected]'}
     LICENSE = 'AGPL-3.0'
     CAN_DETECT = {'Code Simplification', 'Unreachable Code', 'Smell',
                   'Duplication'}
 
-    @classmethod
-    def check_prerequisites(cls):
-        if which('bash') is None:
-            return 'bash is not installed.'
-        elif which('pmd') is None and which('run.sh') is None:
-            return ('PMD is missing. Make sure to install it from '
-                    '<https://pmd.github.io/>')
-        else:
-            return True
-
     @staticmethod
     @deprecate_settings(allow_unnecessary_code=('check_unnecessary', negate),
                         allow_unused_code=('check_unused', negate))
@@ -94,5 +97,6 @@ def create_arguments(filename, file, config_file,
             'java-unusedcode': not allow_unused_code}
         rules = ','.join(key for key in options if options[key])
 
-        executable = which('pmd') or which('run.sh')  # Mac vs. Unix
-        return executable, 'pmd', '-R', rules, '-d', filename
+        executable = tuple(['pmd'] if _executable.endswith('run.sh') else [])
+        arguments = '-R', rules, '-d', filename, '-f', 'text'
+        return executable + arguments

tests/java/JavaPMDBearTest.py

@@ -1,5 +1,3 @@
-from unittest import mock, TestCase
-
 from bears.java.JavaPMDBear import JavaPMDBear
 from coalib.testing.LocalBearTestHelper import verify_local_bear
 
@@ -31,24 +29,6 @@ class Hello {
 """
 
 
-class JavaPMDBearPrerequisiteTest(TestCase):
-    def test_check_prerequisites(self):
-        with mock.patch('bears.java.JavaPMDBear.which') as mock_which:
-            mock_which.side_effect = [None, None, None]
-            self.assertEqual(JavaPMDBear.check_prerequisites(),
-                             'bash is not installed.')
-
-            mock_which.side_effect = ['path/to/bash', None, None]
-            self.assertEqual(JavaPMDBear.check_prerequisites(),
-                             ('PMD is missing. Make sure to install it from '
-                              '<https://pmd.github.io/>'))
-
-            mock_which.side_effect = ['path/to/bash',
-                                      'path/to/pmd',
-                                      'path/to/run']
-            self.assertEqual(JavaPMDBear.check_prerequisites(), True)
-
-
 JavaPMDBearTest = verify_local_bear(
     JavaPMDBear, valid_files=(good_file,), invalid_files=(bad_file,),
     tempfile_kwargs={'suffix': '.java'})