Upgrade Checkstyle tool version to 10.21.2. (#577)

New violations:

- UnnecessaryParentheses (8.42)
- EmptyLineSeparator (10.0)

build.gradle

@@ -165,7 +165,7 @@ subprojects {
   }
 
   checkstyle {
-    toolVersion '8.30'
+    toolVersion '10.21.2'
     checkstyleTest.enabled = false
   }
 

metafacture-triples/src/main/java/org/metafacture/triples/TripleFilter.java

@@ -134,7 +134,7 @@ public void process(final Triple obj) {
 
         final boolean matches = subjectMatcher.matches() || predicateMatcher.matches() || objectMatcher.matches();
 
-        if ((matches && passMatches) || (!matches && !passMatches)) {
+        if (matches == passMatches) {
             getReceiver().process(obj);
         }
     }

metafix/src/main/java/org/metafacture/metafix/FixPath.java

@@ -324,6 +324,7 @@ private enum ReservedField {
         $prepend, $append, $first, $last;
 
         private static final Map<String, ReservedField> STRING_TO_ENUM = new HashMap<>();
+
         static {
             for (final ReservedField f : values()) {
                 STRING_TO_ENUM.put(f.toString(), f);

metamorph/src/main/java/org/metafacture/metamorph/collectors/Range.java

@@ -78,7 +78,7 @@ protected void receive(final String name, final String value, final NamedValueSo
         }
         else {
             final int last = Integer.valueOf(value).intValue();
-            for (int i = first.intValue(); (increment > 0 && i <= last) || (increment < 0 && i >= last); i += increment) {
+            for (int i = first.intValue(); i == last || increment > 0 == i < last; i += increment) {
                 values.add(Integer.valueOf(i));
             }
             first = null;

metamorph/src/main/java/org/metafacture/metamorph/maps/FileMap.java

@@ -197,11 +197,11 @@ private void loadFile(final String file) {
     }
 
     private boolean ignore(final String line) {
-        return line.isEmpty() || (ignoreMatcher != null && ignoreMatcher.reset(line).matches());
+        return line.isEmpty() || ignoreMatcher != null && ignoreMatcher.reset(line).matches();
     }
 
     private boolean ignore(final int partsLength, final int minColumns, final int expColumns) {
-        return partsLength < minColumns || (expColumns > 0 && partsLength != expColumns);
+        return partsLength < minColumns || expColumns > 0 && partsLength != expColumns;
     }
 
     private InputStream openStream(final String file) {