KEYCLOAK-16567 Optimize StackUtil class

tsaarni · Dec 10, 2020 · f053675 · f053675
1 parent 8e376ae
commit f053675
Showing 1 changed file with 39 additions and 15 deletions.
diff --git a/common/src/main/java/org/keycloak/common/util/StackUtil.java b/common/src/main/java/org/keycloak/common/util/StackUtil.java
@@ -1,5 +1,6 @@
 package org.keycloak.common.util;
 
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Pattern;
 import org.jboss.logging.Logger;
 
@@ -11,6 +12,8 @@ public class StackUtil {
 
     private static final Logger LOG = Logger.getLogger("org.keycloak.STACK_TRACE");
 
+    private static final ConcurrentHashMap<String, Object> STACK_TRACE_OBJECTS = new ConcurrentHashMap<>();
+
     /**
      * Returns string representation of the stack trace of the current call
      * without the call to the {@code getShortStackTrace} itself, and ignoring
@@ -24,11 +27,11 @@ public class StackUtil {
      * @return If the logger {@code org.keycloak.STACK_TRACE} is set to trace
      * level, then returns stack trace, else returns empty {@link StringBuilder}
      */
-    public static StringBuilder getShortStackTrace() {
+    public static Object getShortStackTrace() {
         return getShortStackTrace("\n    ");
     }
 
-    private static final Pattern IGNORED = Pattern.compile("^sun\\.|java\\.lang\\.reflect\\.");
+    private static final Pattern IGNORED = Pattern.compile("sun\\.|java\\.(lang|util|stream)\\.|org\\.jboss\\.logging.");
     private static final StringBuilder EMPTY = new StringBuilder(0);
 
     /**
@@ -43,22 +46,43 @@ public static StringBuilder getShortStackTrace() {
      * @return If the logger {@code org.keycloak.STACK_TRACE} is set to trace
      * level, then returns stack trace, else returns empty {@link StringBuilder}
      */
-    public static StringBuilder getShortStackTrace(String prefix) {
+    public static Object getShortStackTrace(final String prefix) {
         if (! isShortStackTraceEnabled()) return EMPTY;
 
-        StringBuilder sb = new StringBuilder();
-        StackTraceElement[] stackTrace = (new Throwable()).getStackTrace();
-        for (int endIndex = 2; endIndex < stackTrace.length; endIndex++) {
-            StackTraceElement st = stackTrace[endIndex];
-            if (IGNORED.matcher(st.getClassName()).find()) {
-                continue;
-            }
-            if (st.getClassName().startsWith("org.jboss.resteasy")) {
-                break;
-            }
-            sb.append(prefix).append(st);
+        Object res = STACK_TRACE_OBJECTS.get(prefix);
+        if (res == null) {
+            res = stackTraceObject(prefix);
+            // Do not synchronize. We don't care if the objects in the map get overridden, they are in the end the same.
+            STACK_TRACE_OBJECTS.put(prefix, res);
         }
-        return sb;
+        return res;
+    }
+
+    private static Object stackTraceObject(final String prefix) {
+        return new Object() {
+            @Override
+            public String toString() {
+                StringBuilder sb = new StringBuilder();
+                StackTraceElement[] stackTrace = (new Throwable()).getStackTrace();
+                boolean stackTraceStarted = false;
+                for (int endIndex = 0; endIndex < stackTrace.length; endIndex++) {
+                    StackTraceElement st = stackTrace[endIndex];
+                    if (! stackTraceStarted) {
+                        stackTraceStarted = (getClass().getName().equals(st.getClassName()));
+                        endIndex++;
+                        continue;
+                    }
+                    if (IGNORED.matcher(st.getClassName()).find()) {
+                        continue;
+                    }
+                    if (st.getClassName().startsWith("org.jboss.resteasy")) {
+                        break;
+                    }
+                    sb.append(prefix).append(st);
+                }
+                return sb.toString();
+            }
+        };
     }
 
     public static boolean isShortStackTraceEnabled() {