InstrumentationProperties avoids string concat when no instrument properties are set (#1717)

InstrumentationProperties avoids string concat when no instrument properties are set

Author: schlosna

changelog/@unreleased/pr-1717.v2.yml

@@ -0,0 +1,6 @@
+type: improvement
+improvement:
+  description: InstrumentationProperties avoids string concat when no instrument properties
+    are set
+  links:
+  - https://github.com/palantir/tritium/pull/1717

tritium-core/src/main/java/com/palantir/tritium/event/InstrumentationProperties.java

@@ -29,7 +29,6 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
-import javax.annotation.Nullable;
 
 public final class InstrumentationProperties {
     private static final SafeLogger log = SafeLoggerFactory.get(InstrumentationProperties.class);
@@ -53,26 +52,25 @@ public static boolean isSpecificEnabled(String name) {
 
     @SuppressWarnings("WeakerAccess") // public API
     public static boolean isSpecificEnabled(String name, boolean defaultValue) {
-        String qualifiedValue = getSpecific(name);
+        Map<String, String> props = instrumentationProperties.get();
+        // avoid string concatenation allocation in common case where no `instrument` properties are defined
+        if (props.isEmpty()) {
+            return defaultValue;
+        }
+        String qualifiedValue = props.get(INSTRUMENT_PREFIX + "." + name);
         if (qualifiedValue == null) {
             return defaultValue;
         }
         return "true".equalsIgnoreCase(qualifiedValue);
     }
 
-    /** Applies the {@link #INSTRUMENT_PREFIX} and returns the current value. */
-    @Nullable
-    private static String getSpecific(String name) {
-        return instrumentationProperties().get(INSTRUMENT_PREFIX + "." + name);
-    }
-
     @SuppressWarnings("WeakerAccess") // public API
     public static boolean isGloballyEnabled() {
         return !isGloballyDisabled();
     }
 
     private static boolean isGloballyDisabled() {
-        return "false".equalsIgnoreCase(instrumentationProperties().get(INSTRUMENT_PREFIX));
+        return "false".equalsIgnoreCase(instrumentationProperties.get().get(INSTRUMENT_PREFIX));
     }
 
     /**
@@ -90,10 +88,6 @@ private static Supplier<Map<String, String>> createSupplier() {
                 InstrumentationProperties::createInstrumentationSystemProperties, 1L, TimeUnit.MINUTES);
     }
 
-    private static Map<String, String> instrumentationProperties() {
-        return instrumentationProperties.get();
-    }
-
     private static ImmutableMap<String, String> createInstrumentationSystemProperties() {
         /*
          * Since system properties are backed by a java.util.Hashtable, they can be
@@ -112,7 +106,9 @@ private static ImmutableMap<String, String> createInstrumentationSystemPropertie
                         && String.valueOf(entry.getKey()).startsWith(INSTRUMENT_PREFIX))
                 .collect(ImmutableMap.toImmutableMap(
                         entry -> String.valueOf(entry.getKey()), entry -> String.valueOf(entry.getValue())));
-        log.debug("Reloaded instrumentation properties {}", UnsafeArg.of("instrumentationProperties", map));
+        if (log.isDebugEnabled()) {
+            log.debug("Reloaded instrumentation properties", UnsafeArg.of("instrumentationProperties", map));
+        }
         return map;
     }
 }