Incorporating feedback from code review

1.) splitting out the default/regex tests
2.) updating the configuration reference and
3.) supporting caching of compiled regex expressions

docs/source/manual/configuration.rst

@@ -630,6 +630,7 @@ durationUnit           milliseconds   The unit to report durations as. Overrides
 rateUnit               seconds        The unit to report rates as. Overrides per-metric rate units.
 excludes               (none)         Metrics to exclude from reports, by name. When defined, matching metrics will not be reported.
 includes               (all)          Metrics to include in reports, by name. When defined, only these metrics will be reported.
+useRegexFilters        false          Indicates whether the values of the 'includes' and 'excludes' fields should be treated as regular expressions or not.
 frequency              (none)         The frequency to report metrics. Overrides the default.
 ====================== =============  ===========
 

dropwizard-metrics/src/main/java/io/dropwizard/metrics/BaseReporterFactory.java

@@ -5,6 +5,9 @@
 import com.codahale.metrics.ScheduledReporter;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.base.Optional;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
 import com.google.common.collect.ImmutableSet;
 import io.dropwizard.util.Duration;
 
@@ -203,10 +206,23 @@ public boolean containsMatch(ImmutableSet<String> matchExpressions, String metri
     }
 
     private static class RegexStringMatchingStrategy implements StringMatchingStrategy {
+        private final LoadingCache<String, Pattern> patternCache;
+
+        private RegexStringMatchingStrategy() {
+            patternCache = CacheBuilder.newBuilder()
+                    .expireAfterWrite(1, TimeUnit.HOURS)
+                    .build(new CacheLoader<String, Pattern>() {
+                        @Override
+                        public Pattern load(String regex) throws Exception {
+                            return Pattern.compile(regex);
+                        }
+                    });
+        }
+
         @Override
         public boolean containsMatch(ImmutableSet<String> matchExpressions, String metricName) {
             for (String regexExpression : matchExpressions) {
-                if (Pattern.matches(regexExpression, metricName)) {
+                if (patternCache.getUnchecked(regexExpression).matcher(metricName).matches()) {
                     // just need to match on a single value - return as soon as we do
                     return true;
                 }

dropwizard-metrics/src/test/java/io/dropwizard/metrics/BaseReporterFactoryTest.java

@@ -103,14 +103,20 @@ public ScheduledReporter build(MetricRegistry registry) {
     private final Metric metric = mock(Metric.class);
 
     @Test
-    public void matches() {
+    public void testDefaultMatching() {
         factory.setIncludes(includes);
         factory.setExcludes(excludes);
 
         factory.setUseRegexFilters(false);
         assertThat(factory.getFilter().matches(name, metric))
                 .overridingErrorMessage(msg + ": expected 'matches(%s)=%s' for default matcher", name, expectedDefaultResult)
                 .isEqualTo(expectedDefaultResult);
+    }
+
+    @Test
+    public void testRegexMatching() {
+        factory.setIncludes(includes);
+        factory.setExcludes(excludes);
 
         factory.setUseRegexFilters(true);
         assertThat(factory.getFilter().matches(name, metric))