Compile regex pattern for MetricFilter only once (#2637)

graylog2-server/src/main/java/org/graylog2/periodical/ThroughputCalculator.java

@@ -32,6 +32,8 @@
 import java.util.Map;
 import java.util.SortedMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import static com.codahale.metrics.MetricRegistry.name;
 import static org.graylog2.shared.metrics.MetricUtils.filterSingleMetric;
@@ -41,6 +43,15 @@ public class ThroughputCalculator extends Periodical {
 
     private final MetricRegistry metricRegistry;
 
+    protected static final Pattern incomingMessagesPattern = Pattern.compile("org\\.graylog2\\.plugin\\.streams\\.Stream\\..*?\\.incomingMessages");
+    protected static final MetricFilter streamMetricFilter = new MetricFilter() {
+        @Override
+        public boolean matches(String name, Metric metric) {
+            Matcher matcher = incomingMessagesPattern.matcher(name);
+            return matcher.matches();
+        }
+    };
+
     private ConcurrentMap<String, CounterSample> sampledCounters = Maps.newConcurrentMap();
 
     @Inject
@@ -99,12 +110,7 @@ public void doRun() {
         );
 
         // StreamMetrics isn't accessible here, so we need to use a metrics filter instead.
-        final SortedMap<String, ? extends Counting> streamMeters = metricRegistry.getMeters(new MetricFilter() {
-            @Override
-            public boolean matches(String name, Metric metric) {
-                return name.matches("org\\.graylog2\\.plugin\\.streams\\.Stream\\..*?\\.incomingMessages");
-            }
-        });
+        final SortedMap<String, ? extends Counting> streamMeters = metricRegistry.getMeters(streamMetricFilter);
 
         final Iterable<Map.Entry<String, ? extends Counting>> entries = Iterables.concat(counters.entrySet(),
                                                                                          inputCounters.entrySet(),

graylog2-server/src/test/java/org/graylog2/periodical/ThroughputCalculatorTest.java

@@ -0,0 +1,29 @@
+/**
+ * This file is part of Graylog.
+ *
+ * Graylog is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Graylog is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Graylog.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.graylog2.periodical;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class ThroughputCalculatorTest {
+
+    @Test
+    public void testStreamMetricFilter() {
+        assertTrue("Filter should match stream incomingMessages", ThroughputCalculator.streamMetricFilter.matches("org.graylog2.plugin.streams.Stream.579657c468e16405f90345b0.incomingMessages", null));
+    }
+}