let generateSlots handle multi-slots

Author: HSGamer

src/main/java/me/hsgamer/bettergui/util/SlotUtil.java

@@ -4,8 +4,6 @@
 
 import java.math.BigDecimal;
 import java.util.*;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
@@ -17,7 +15,6 @@ public class SlotUtil {
   private static final String POS_X = "position-x";
   private static final String POS_Y = "position-y";
   private static final String POS_SLOT = "slot";
-  private static final Pattern RANGE_PATTERN = Pattern.compile("([0-9]+)-([0-9]+)");
 
   private SlotUtil() {
     // EMPTY
@@ -45,10 +42,7 @@ public static List<Integer> getSlots(Map<String, Object> map) {
       slots.add((y - 1) * 9 + x - 1);
     }
     if (map.containsKey(POS_SLOT)) {
-      slots.addAll(Arrays
-        .stream(String.valueOf(map.get(POS_SLOT)).split(","))
-        .map(String::trim)
-        .flatMap(SlotUtil::generateSlots).collect(Collectors.toList()));
+      slots.addAll(generateSlots(String.valueOf(map.get(POS_SLOT))).collect(Collectors.toList()));
     }
     return slots;
   }
@@ -61,20 +55,24 @@ public static List<Integer> getSlots(Map<String, Object> map) {
    * @return the stream of slots
    */
   public static Stream<Integer> generateSlots(String input) {
-    Matcher matcher = RANGE_PATTERN.matcher(input);
-    if (matcher.matches()) {
-      int s1 = Integer.parseInt(matcher.group(1));
-      int s2 = Integer.parseInt(matcher.group(2));
-      if (s1 <= s2) {
-        return IntStream.rangeClosed(s1, s2).boxed();
-      } else {
-        return IntStream.rangeClosed(s2, s1).boxed().sorted(Collections.reverseOrder());
-      }
-    }
-
-    return Validate.getNumber(input)
-      .map(BigDecimal::intValue)
-      .map(Stream::of)
-      .orElseGet(Stream::empty);
+    return Arrays.stream(input.split(","))
+      .map(String::trim)
+      .flatMap(rawSlot -> {
+        String[] rangeSplit = rawSlot.split("-", 2);
+        if (rangeSplit.length == 2) {
+          Optional<Integer> start = Validate.getNumber(rangeSplit[0]).map(BigDecimal::intValue);
+          Optional<Integer> end = Validate.getNumber(rangeSplit[1]).map(BigDecimal::intValue);
+          if (start.isPresent() && end.isPresent()) {
+            return IntStream.rangeClosed(start.get(), end.get()).boxed();
+          } else {
+            return Stream.empty();
+          }
+        } else {
+          return Validate.getNumber(input)
+            .map(BigDecimal::intValue)
+            .map(Stream::of)
+            .orElseGet(Stream::empty);
+        }
+      });
   }
 }