Use static regex pattern for excluded path segments

Author: Bartosz Rumiński

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubeChannelLinkHandlerFactory.java

@@ -1,5 +1,6 @@
 package org.schabi.newpipe.extractor.services.youtube.linkHandler;
 
+import java.util.regex.Pattern;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.linkhandler.ListLinkHandlerFactory;
 import org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper;
@@ -49,22 +50,25 @@ public String getUrl(String id, List<String> contentFilters, String searchFilter
         return "https://www.youtube.com/" + id;
     }
 
+
     /**
      * Returns true if path conform to
      * custom short channel URLs like youtube.com/yourcustomname
      *
      * @param splitPath path segments array
      * @return true - if value conform to short channel URL, false - not
      */
-    private boolean isCustomShortChannelUrl(String[] splitPath) {
-        return splitPath.length == 1 &&
-          !splitPath[0].matches("playlist|watch|attribution_link|watch_popup|embed|feed|select_site");
+    private boolean isCustomShortChannelUrl(final String[] splitPath) {
+        return splitPath.length == 1 && !excludedSegments.matcher(splitPath[0]).matches();
     }
 
+  private static final Pattern excludedSegments =
+    Pattern.compile("playlist|watch|attribution_link|watch_popup|embed|feed|select_site");
+
     @Override
     public String getId(String url) throws ParsingException {
         try {
-            URL urlObj = Utils.stringToURL(url);
+            final URL urlObj = Utils.stringToURL(url);
             String path = urlObj.getPath();
 
             if (!Utils.isHTTP(urlObj) || !(YoutubeParsingHelper.isYoutubeURL(urlObj) ||
@@ -86,7 +90,7 @@ public String getId(String url) throws ParsingException {
                 throw new ParsingException("the URL given is neither a channel nor an user");
             }
 
-            String id = splitPath[1];
+            final String id = splitPath[1];
 
             if (id == null || !id.matches("[A-Za-z0-9_-]+")) {
                 throw new ParsingException("The given id is not a Youtube-Video-ID");