use optional instead of providing default for int

Author: zeitlinger

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/internal/ConfigPropertiesUtil.java

@@ -67,16 +67,16 @@ public static Optional<Boolean> getBoolean(OpenTelemetry openTelemetry, String..
    * Returns the int value of the given property name from system properties and environment
    * variables.
    */
-  public static int getInt(String propertyName, int defaultValue) {
-    String strValue = getString(propertyName);
-    if (strValue == null) {
-      return defaultValue;
-    }
-    try {
-      return Integer.parseInt(strValue);
-    } catch (NumberFormatException ignored) {
-      return defaultValue;
-    }
+  public static Optional<Integer> getInt(String propertyName) {
+    return Optional.ofNullable(getString(propertyName))
+        .flatMap(
+            s -> {
+              try {
+                return Optional.of(Integer.parseInt(s));
+              } catch (NumberFormatException ignored) {
+                return Optional.empty();
+              }
+            });
   }
 
   /**

instrumentation-api/src/test/java/io/opentelemetry/instrumentation/api/internal/ConfigPropertiesUtilTest.java

@@ -93,24 +93,24 @@ void getString_declarativeConfig(Object property, String expected) {
   @SetSystemProperty(key = "test.property.int", value = "42")
   @Test
   void getInt_systemProperty() {
-    assertThat(ConfigPropertiesUtil.getInt("test.property.int", -1)).isEqualTo(42);
+    assertThat(ConfigPropertiesUtil.getInt("test.property.int")).hasValue(42);
   }
 
   @SetEnvironmentVariable(key = "TEST_PROPERTY_INT", value = "12")
   @Test
   void getInt_environmentVariable() {
-    assertThat(ConfigPropertiesUtil.getInt("test.property.int", -1)).isEqualTo(12);
+    assertThat(ConfigPropertiesUtil.getInt("test.property.int")).hasValue(12);
   }
 
   @Test
   void getInt_none() {
-    assertThat(ConfigPropertiesUtil.getInt("test.property.int", -1)).isEqualTo(-1);
+    assertThat(ConfigPropertiesUtil.getInt("test.property.int")).isEmpty();
   }
 
   @SetSystemProperty(key = "test.property.int", value = "not a number")
   @Test
   void getInt_invalidNumber() {
-    assertThat(ConfigPropertiesUtil.getInt("test.property.int", -1)).isEqualTo(-1);
+    assertThat(ConfigPropertiesUtil.getInt("test.property.int")).isEmpty();
   }
 
   @SetEnvironmentVariable(key = "OTEL_INSTRUMENTATION_TEST_PROPERTY_BOOLEAN", value = "false")

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/config/EarlyInitAgentConfig.java

@@ -46,7 +46,7 @@ public int getInt(String propertyName, int defaultValue) {
       String configFileValueStr = configFileContents.get(propertyName);
       int configFileValue =
           configFileValueStr == null ? defaultValue : Integer.parseInt(configFileValueStr);
-      return ConfigPropertiesUtil.getInt(propertyName, configFileValue);
+      return ConfigPropertiesUtil.getInt(propertyName).orElse(configFileValue);
     } catch (NumberFormatException ignored) {
       return defaultValue;
     }