[GitHub] reta commented on a change in pull request #479: String.split via fastpath instead of precompiled Pattern

[GitBox <gi...@apache.org>]

reta commented on a change in pull request #479: String.split via fastpath instead of precompiled Pattern
URL: https://github.com/apache/cxf/pull/479#discussion_r239430809
 
 

 ##########
 File path: core/src/main/java/org/apache/cxf/common/util/StringUtils.java
 ##########
 @@ -26,37 +26,33 @@
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Predicate;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
 public final class StringUtils {
-    public static final Map<String, Pattern> PATTERN_MAP = new HashMap<>();
-    static {
-        String[] patterns = {"/", " ", ":", ",", ";", "=", "\\.", "\\+"};
-        for (String p : patterns) {
-            PATTERN_MAP.put(p, Pattern.compile(p));
-        }
-    }
+    private static final Map<String, Pattern> PATTERN_MAP = new ConcurrentHashMap<>();
     private static final Predicate<String> NOT_EMPTY = (String s) -> !s.isEmpty();
 
     private StringUtils() {
     }
 
+    /* String.split via fastpath preferred */
     public static String[] split(String s, String regex) {
         return split(s, regex, 0);
     }
+    @Deprecated
     public static String[] split(String s, String regex, int limit) {
-        Pattern p = PATTERN_MAP.getOrDefault(regex, Pattern.compile(regex));
+        Pattern p = PATTERN_MAP.computeIfAbsent(regex, key -> Pattern.compile(key));
 
 Review comment:
   There is an well-known issue with JDK8 related to `computeIfAbsent`, https://bugs.openjdk.java.net/browse/JDK-8161372, not sure if we should take into account or not ... 

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