chore: various improvements as suggested by sonar (#674)

Signed-off-by: Kavindu Dodanduwa <kavindudodanduwa@gmail.com>

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/common/ChannelBuilder.java

@@ -18,6 +18,10 @@
  * gRPC channel builder helper.
  */
 public class ChannelBuilder {
+
+    private ChannelBuilder() {
+    }
+
     /**
      * This method is a helper to build a {@link ManagedChannel} from provided {@link FlagdOptions}.
      */

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/common/Util.java

@@ -6,6 +6,10 @@
  * Utils for flagd resolvers.
  */
 public class Util {
+
+    private Util() {
+    }
+
     /**
      * A helper to block the caller for given conditions.
      *

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/grpc/EventStreamObserver.java

@@ -102,7 +102,7 @@ private void handleProviderReadyEvent() {
 
     private void handleEndOfStream() {
         synchronized (this.sync) {
-            this.sync.notify();
+            this.sync.notifyAll();
         }
     }
 }

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/grpc/GrpcConnector.java

@@ -26,7 +26,6 @@ public class GrpcConnector {
     private final Object sync = new Object();
     private final AtomicBoolean connected = new AtomicBoolean(false);
     private final Random random = new Random();
-    private final int maxJitter = 100;
 
     private final ServiceGrpc.ServiceBlockingStub serviceBlockingStub;
     private final ServiceGrpc.ServiceStub serviceStub;
@@ -129,19 +128,19 @@ private void observeEventStream() {
                 // Interruptions are considered end calls for this observer, hence log and return
                 // Note - this is the most common interruption when shutdown, hence the log level debug
                 log.debug("interruption while waiting for condition", e);
-                return;
+                Thread.currentThread().interrupt();
             }
 
             this.eventStreamAttempt++;
             // backoff with a jitter
-            this.eventStreamRetryBackoff = 2 * this.eventStreamRetryBackoff + random.nextInt(maxJitter);
+            this.eventStreamRetryBackoff = 2 * this.eventStreamRetryBackoff + random.nextInt(100);
 
             try {
                 Thread.sleep(this.eventStreamRetryBackoff);
             } catch (InterruptedException e) {
                 // Interruptions are considered end calls for this observer, hence log and return
                 log.warn("interrupted while restarting gRPC Event Stream");
-                return;
+                Thread.currentThread().interrupt();
             }
         }
 

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/grpc/cache/Cache.java

@@ -16,7 +16,7 @@
  */
 @Slf4j
 public class Cache {
-    private Map<String, ProviderEvaluation<? extends Object>> store;
+    private Map<String, ProviderEvaluation<?>> store;
 
     @Getter
     private final Boolean enabled;
@@ -39,11 +39,11 @@ public Cache(final String forType, int maxCacheSize) {
         }
     }
 
-    public void put(String key, ProviderEvaluation<? extends Object> value) {
+    public void put(String key, ProviderEvaluation<?> value) {
         this.store.put(key, value);
     }
 
-    public ProviderEvaluation<? extends Object> get(String key) {
+    public ProviderEvaluation<?> get(String key) {
         return this.store.get(key);
     }
 

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/grpc/strategy/ResolveFactory.java

@@ -6,6 +6,10 @@
  * Factory to create a ResolveStrategy.
  */
 public final class ResolveFactory {
+
+    private ResolveFactory() {
+    }
+
     /**
      * Factory method to initialize the resolving strategy.
      *

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/InProcessResolver.java

@@ -82,6 +82,7 @@ public void init() throws Exception {
                 }
             } catch (InterruptedException e) {
                 log.warn("Storage state watcher interrupted", e);
+                Thread.currentThread().interrupt();
             }
         });
         stateWatcher.setDaemon(true);

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/model/FlagParser.java

@@ -32,12 +32,13 @@ public class FlagParser {
     private static final String SCHEMA_RESOURCE = "flagd-definitions.json";
 
     private static final ObjectMapper MAPPER = new ObjectMapper();
-
     private static final Map<String, Pattern> PATTERN_MAP = new HashMap<>();
-    private static final Pattern REG_BRACKETS = Pattern.compile("^[^{]*\\{|}[^}]*$");
 
     private static JsonSchema SCHEMA_VALIDATOR;
 
+    private FlagParser() {
+    }
+
     static {
         try (InputStream schema = FlagParser.class.getClassLoader().getResourceAsStream(SCHEMA_RESOURCE)) {
             if (schema == null) {
@@ -110,8 +111,9 @@ private static String transposeEvaluators(final String configuration) throws IOE
 
             while (evalFields.hasNext()) {
                 final String evalName = evalFields.next();
-                // first replace brackets
-                final String replacer = REG_BRACKETS.matcher(evaluators.get(evalName).toString()).replaceAll("");
+                // first replace outmost brackets
+                final String evaluator = evaluators.get(evalName).toString();
+                final String replacer = evaluator.substring(1, evaluator.length() - 1);
 
                 final String replacePattern = String.format(REPLACER_FORMAT, evalName);
 

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/FlagStore.java

@@ -47,6 +47,7 @@ public void init() throws Exception {
                 streamerListener(connector);
             } catch (InterruptedException e) {
                 log.warn("connection listener failed", e);
+                Thread.currentThread().interrupt();
             }
         });
         streamer.setDaemon(true);

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/connector/file/FileConnector.java

@@ -25,6 +25,7 @@
 public class FileConnector implements Connector {
 
     private static final int POLL_INTERVAL_MS = 5000;
+    private static final String OFFER_WARN = "Unable to offer file content to queue: queue is full";
 
     private final String flagSourcePath;
     private final BlockingQueue<StreamPayload> queue = new LinkedBlockingQueue<>(1);
@@ -45,7 +46,7 @@ public void init() throws IOException {
                 // initial read
                 String flagData = new String(Files.readAllBytes(filePath), StandardCharsets.UTF_8);
                 if (!queue.offer(new StreamPayload(StreamPayloadType.DATA, flagData))) {
-                    log.warn("Unable to offer file content to queue: queue is full");
+                    log.warn(OFFER_WARN);
                 }
 
                 long lastTS = Files.getLastModifiedTime(filePath).toMillis();
@@ -58,18 +59,21 @@ public void init() throws IOException {
                         lastTS = currentTS;
                         flagData = new String(Files.readAllBytes(filePath), StandardCharsets.UTF_8);
                         if (!queue.offer(new StreamPayload(StreamPayloadType.DATA, flagData))) {
-                            log.warn("Unable to offer file content to queue: queue is full");
+                            log.warn(OFFER_WARN);
                         }
                     }
 
                     Thread.sleep(POLL_INTERVAL_MS);
                 }
 
                 log.info("Shutting down file connector.");
+            } catch (InterruptedException ex) {
+                log.error("Interrupted while waiting for polling", ex);
+                Thread.currentThread().interrupt();
             } catch (Throwable t) {
                 log.error("Error from file connector. File connector will exit", t);
                 if (!queue.offer(new StreamPayload(StreamPayloadType.ERROR, t.toString()))) {
-                    log.warn("Unable to offer file content to queue: queue is full");
+                    log.warn(OFFER_WARN);
                 }
             }
         });

providers/flagd/src/main/java/dev/openfeature/contrib/providers/flagd/resolver/process/storage/connector/grpc/GrpcStreamConnector.java

@@ -66,6 +66,7 @@ public void init() {
                 observeEventStream(blockingQueue, shutdown, serviceStub, requestBuilder.build());
             } catch (InterruptedException e) {
                 log.warn("gRPC event stream interrupted, flag configurations are stale", e);
+                Thread.currentThread().interrupt();
             }
         });
 

providers/flagd/src/test/java/dev/openfeature/contrib/providers/flagd/FlagdOptionsTest.java

@@ -20,14 +20,14 @@ public class FlagdOptionsTest {
     public void TestDefaults() {
         final FlagdOptions builder = FlagdOptions.builder().build();
 
-        assertEquals(builder.getHost(), DEFAULT_HOST);
-        assertEquals(Integer.toString(builder.getPort()), DEFAULT_PORT);
+        assertEquals(DEFAULT_HOST, builder.getHost());
+        assertEquals(DEFAULT_PORT, Integer.toString(builder.getPort()));
         assertFalse(builder.isTls());
         assertNull(builder.getCertPath());
         assertNull(builder.getSocketPath());
-        assertEquals(builder.getCacheType(), DEFAULT_CACHE);
-        assertEquals(builder.getMaxCacheSize(), DEFAULT_MAX_CACHE_SIZE);
-        assertEquals(builder.getMaxEventStreamRetries(), DEFAULT_MAX_EVENT_STREAM_RETRIES);
+        assertEquals(DEFAULT_CACHE, builder.getCacheType());
+        assertEquals(DEFAULT_MAX_CACHE_SIZE, builder.getMaxCacheSize());
+        assertEquals(DEFAULT_MAX_EVENT_STREAM_RETRIES, builder.getMaxEventStreamRetries());
         assertNull(builder.getSelector());
         assertNull(builder.getOpenTelemetry());
         assertNull(builder.getOfflineFlagSourcePath());
@@ -50,15 +50,15 @@ public void TestBuilderOptions() {
                 .openTelemetry(openTelemetry)
                 .build();
 
-        assertEquals(flagdOptions.getHost(), "https://hosted-flagd");
-        assertEquals(flagdOptions.getPort(), 80);
+        assertEquals("https://hosted-flagd", flagdOptions.getHost());
+        assertEquals(80, flagdOptions.getPort());
         assertTrue(flagdOptions.isTls());
-        assertEquals(flagdOptions.getCertPath(), "etc/cert/ca.crt");
-        assertEquals(flagdOptions.getCacheType(), "lru");
-        assertEquals(flagdOptions.getMaxCacheSize(), 100);
-        assertEquals(flagdOptions.getMaxEventStreamRetries(), 1);
-        assertEquals(flagdOptions.getSelector(), "app=weatherApp");
+        assertEquals("etc/cert/ca.crt", flagdOptions.getCertPath());
+        assertEquals("lru", flagdOptions.getCacheType());
+        assertEquals(100, flagdOptions.getMaxCacheSize());
+        assertEquals(1, flagdOptions.getMaxEventStreamRetries());
+        assertEquals("app=weatherApp", flagdOptions.getSelector());
         assertEquals("some-path", flagdOptions.getOfflineFlagSourcePath());
-        assertEquals(flagdOptions.getOpenTelemetry(), openTelemetry);
+        assertEquals(openTelemetry, flagdOptions.getOpenTelemetry());
     }
 }