[FLINK-8280][checkstyle] enable and fix checkstyle in BlobServer and BlobUtils

This closes #5175.

flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobClient.java

@@ -119,7 +119,7 @@ public final class BlobClient implements Closeable {
 			}
 
 		}
-		catch(Exception e) {
+		catch (Exception e) {
 			BlobUtils.closeSilently(socket, LOG);
 			throw new IOException("Could not connect to BlobServer at address " + serverAddress, e);
 		}

flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobInputStream.java

@@ -50,7 +50,7 @@ final class BlobInputStream extends InputStream {
 	private final OutputStream wrappedOutputStream;
 
 	/**
-	 * The BLOB key if the GET operation has been performed on a content-addressable BLOB, otherwise <code>null<code>.
+	 * The BLOB key if the GET operation has been performed on a content-addressable BLOB, otherwise <code>null</code>.
 	 */
 	private final BlobKey blobKey;
 

flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobServer.java

@@ -77,28 +77,28 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 	/** The server socket listening for incoming connections. */
 	private final ServerSocket serverSocket;
 
-	/** The SSL server context if ssl is enabled for the connections */
+	/** The SSL server context if ssl is enabled for the connections. */
 	private final SSLContext serverSSLContext;
 
-	/** Blob Server configuration */
+	/** Blob Server configuration. */
 	private final Configuration blobServiceConfiguration;
 
 	/** Indicates whether a shutdown of server component has been requested. */
 	private final AtomicBoolean shutdownRequested = new AtomicBoolean();
 
-	/** Root directory for local file storage */
+	/** Root directory for local file storage. */
 	private final File storageDir;
 
-	/** Blob store for distributed file storage, e.g. in HA */
+	/** Blob store for distributed file storage, e.g. in HA. */
 	private final BlobStore blobStore;
 
-	/** Set of currently running threads */
+	/** Set of currently running threads. */
 	private final Set<BlobServerConnection> activeConnections = new HashSet<>();
 
-	/** The maximum number of concurrent connections */
+	/** The maximum number of concurrent connections. */
 	private final int maxConnections;
 
-	/** Lock guarding concurrent file accesses */
+	/** Lock guarding concurrent file accesses. */
 	private final ReadWriteLock readWriteLock;
 
 	/**
@@ -201,8 +201,8 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 			}
 		});
 
-		if(socketAttempt == null) {
-			throw new IOException("Unable to allocate socket for blob server in specified port range: "+serverPortRange);
+		if (socketAttempt == null) {
+			throw new IOException("Unable to allocate socket for blob server in specified port range: " + serverPortRange);
 		} else {
 			SSLUtils.setSSLVerAndCipherSuites(socketAttempt, config);
 			this.serverSocket = socketAttempt;
@@ -254,7 +254,7 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 	}
 
 	/**
-	 * Returns the lock used to guard file accesses
+	 * Returns the lock used to guard file accesses.
 	 */
 	ReadWriteLock getReadWriteLock() {
 		return readWriteLock;
@@ -360,7 +360,7 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 				}
 			}
 
-			if(LOG.isInfoEnabled()) {
+			if (LOG.isInfoEnabled()) {
 				LOG.info("Stopped BLOB server at {}:{}", serverSocket.getInetAddress().getHostAddress(), getPort());
 			}
 
@@ -375,8 +375,8 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 
 	/**
 	 * Retrieves the local path of a (job-unrelated) file associated with a job and a blob key.
-	 * <p>
-	 * The blob server looks the blob key up in its local storage. If the file exists, it is
+	 *
+	 * <p>The blob server looks the blob key up in its local storage. If the file exists, it is
 	 * returned. If the file does not exist, it is retrieved from the HA blob store (if available)
 	 * or a {@link FileNotFoundException} is thrown.
 	 *
@@ -395,8 +395,8 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 
 	/**
 	 * Retrieves the local path of a file associated with a job and a blob key.
-	 * <p>
-	 * The blob server looks the blob key up in its local storage. If the file exists, it is
+	 *
+	 * <p>The blob server looks the blob key up in its local storage. If the file exists, it is
 	 * returned. If the file does not exist, it is retrieved from the HA blob store (if available)
 	 * or a {@link FileNotFoundException} is thrown.
 	 *
@@ -419,8 +419,8 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 	/**
 	 * Returns the path to a local copy of the file associated with the provided job ID and blob
 	 * key.
-	 * <p>
-	 * We will first attempt to serve the BLOB from the local storage. If the BLOB is not in
+	 *
+	 * <p>We will first attempt to serve the BLOB from the local storage. If the BLOB is not in
 	 * there, we will try to download it from the HA store.
 	 *
 	 * @param jobId
@@ -443,8 +443,8 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 
 	/**
 	 * Retrieves the local path of a file associated with a job and a blob key.
-	 * <p>
-	 * The blob server looks the blob key up in its local storage. If the file exists, it is
+	 *
+	 * <p>The blob server looks the blob key up in its local storage. If the file exists, it is
 	 * returned. If the file does not exist, it is retrieved from the HA blob store (if available)
 	 * or a {@link FileNotFoundException} is thrown.
 	 *
@@ -474,12 +474,12 @@ public class BlobServer extends Thread implements BlobService, BlobWriter, Perma
 
 	/**
 	 * Helper to retrieve the local path of a file associated with a job and a blob key.
-	 * <p>
-	 * The blob server looks the blob key up in its local storage. If the file exists, it is
+	 *
+	 * <p>The blob server looks the blob key up in its local storage. If the file exists, it is
 	 * returned. If the file does not exist, it is retrieved from the HA blob store (if available)
 	 * or a {@link FileNotFoundException} is thrown.
-	 * <p>
-	 * <strong>Assumes the read lock has already been acquired.</strong>
+	 *
+	 * <p><strong>Assumes the read lock has already been acquired.</strong>
 	 *
 	 * @param jobId
 	 * 		ID of the job this blob belongs to (or <tt>null</tt> if job-unrelated)

flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobServerProtocol.java

@@ -15,8 +15,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.flink.runtime.blob;
 
+/**
+ * Defines constants for the protocol between the BLOB {@link BlobServer server} and the
+ * {@link AbstractBlobCache caches}.
+ */
 public class BlobServerProtocol {
 
 	// --------------------------------------------------------------------------------------------

flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobUtils.java

@@ -150,8 +150,8 @@ public class BlobUtils {
 		File storageDir;
 
 		// NOTE: although we will be using UUIDs, there may be collisions
-		final int MAX_ATTEMPTS = 10;
-		for(int attempt = 0; attempt < MAX_ATTEMPTS; attempt++) {
+		int maxAttempts = 10;
+		for (int attempt = 0; attempt < maxAttempts; attempt++) {
 			storageDir = new File(baseDir, String.format(
 					"blobStore-%s", UUID.randomUUID().toString()));
 
@@ -251,8 +251,8 @@ public class BlobUtils {
 
 	/**
 	 * Returns the path for the given blob key.
-	 * <p>
-	 * The returned path can be used with the (local or HA) BLOB store file system back-end for
+	 *
+	 * <p>The returned path can be used with the (local or HA) BLOB store file system back-end for
 	 * recovery purposes and follows the same scheme as {@link #getStorageLocation(File, JobID,
 	 * BlobKey)}.
 	 *
@@ -403,12 +403,12 @@ public class BlobUtils {
 		}
 	}
 
-	static void closeSilently(Socket socket, Logger LOG) {
+	static void closeSilently(Socket socket, Logger log) {
 		if (socket != null) {
 			try {
 				socket.close();
 			} catch (Throwable t) {
-				LOG.debug("Exception while closing BLOB server connection socket.", t);
+				log.debug("Exception while closing BLOB server connection socket.", t);
 			}
 		}
 	}

flink-runtime/src/main/java/org/apache/flink/runtime/blob/FileSystemBlobStore.java

@@ -46,10 +46,10 @@ public class FileSystemBlobStore implements BlobStoreService {
 
 	private static final Logger LOG = LoggerFactory.getLogger(FileSystemBlobStore.class);
 
-	/** The file system in which blobs are stored */
+	/** The file system in which blobs are stored. */
 	private final FileSystem fileSystem;
 
-	/** The base path of the blob store */
+	/** The base path of the blob store. */
 	private final String basePath;
 
 	public FileSystemBlobStore(FileSystem fileSystem, String storagePath) throws IOException {

flink-runtime/src/test/java/org/apache/flink/runtime/blob/BlobCacheGetTest.java

@@ -78,7 +78,7 @@ import static org.mockito.Mockito.mock;
 /**
  * Tests for GET-specific parts of the {@link BlobCacheService}.
  *
- * This includes access of transient BLOBs from the {@link PermanentBlobCache}, permanent BLOBS from
+ * <p>This includes access of transient BLOBs from the {@link PermanentBlobCache}, permanent BLOBS from
  * the {@link TransientBlobCache}, and how failing GET requests behave in the presence of failures
  * when used with a {@link BlobCacheService}.
  *

flink-runtime/src/test/java/org/apache/flink/runtime/blob/BlobClientSslTest.java

@@ -36,10 +36,10 @@ import java.io.IOException;
 public class BlobClientSslTest extends BlobClientTest {
 
 	/** The instance of the SSL BLOB server used during the tests. */
-	private static BlobServer BLOB_SSL_SERVER;
+	private static BlobServer blobSslServer;
 
 	/** Instance of a non-SSL BLOB server with SSL-enabled security options. */
-	private static BlobServer BLOB_NON_SSL_SERVER;
+	private static BlobServer blobNonSslServer;
 
 	/** The SSL blob service client configuration. */
 	private static Configuration sslClientConfig;
@@ -62,8 +62,8 @@ public class BlobClientSslTest extends BlobClientTest {
 		config.setString(SecurityOptions.SSL_KEYSTORE, "src/test/resources/local127.keystore");
 		config.setString(SecurityOptions.SSL_KEYSTORE_PASSWORD, "password");
 		config.setString(SecurityOptions.SSL_KEY_PASSWORD, "password");
-		BLOB_SSL_SERVER = new BlobServer(config, new VoidBlobStore());
-		BLOB_SSL_SERVER.start();
+		blobSslServer = new BlobServer(config, new VoidBlobStore());
+		blobSslServer.start();
 
 		sslClientConfig = new Configuration();
 		sslClientConfig.setBoolean(SecurityOptions.SSL_ENABLED, true);
@@ -81,8 +81,8 @@ public class BlobClientSslTest extends BlobClientTest {
 		config.setString(SecurityOptions.SSL_KEYSTORE, "src/test/resources/local127.keystore");
 		config.setString(SecurityOptions.SSL_KEYSTORE_PASSWORD, "password");
 		config.setString(SecurityOptions.SSL_KEY_PASSWORD, "password");
-		BLOB_NON_SSL_SERVER = new BlobServer(config, new VoidBlobStore());
-		BLOB_NON_SSL_SERVER.start();
+		blobNonSslServer = new BlobServer(config, new VoidBlobStore());
+		blobNonSslServer.start();
 
 		nonSslClientConfig = new Configuration();
 		nonSslClientConfig.setBoolean(SecurityOptions.SSL_ENABLED, true);
@@ -96,11 +96,11 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@AfterClass
 	public static void stopServers() throws IOException {
-		if (BLOB_SSL_SERVER != null) {
-			BLOB_SSL_SERVER.close();
+		if (blobSslServer != null) {
+			blobSslServer.close();
 		}
-		if (BLOB_NON_SSL_SERVER != null) {
-			BLOB_NON_SSL_SERVER.close();
+		if (blobNonSslServer != null) {
+			blobNonSslServer.close();
 		}
 	}
 
@@ -109,7 +109,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	}
 
 	protected BlobServer getBlobServer() {
-		return BLOB_SSL_SERVER;
+		return blobSslServer;
 	}
 
 	/**
@@ -117,7 +117,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@Test
 	public void testUploadJarFilesHelper() throws Exception {
-		uploadJarFile(BLOB_SSL_SERVER, sslClientConfig);
+		uploadJarFile(blobSslServer, sslClientConfig);
 	}
 
 	/**
@@ -126,7 +126,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	@Test(expected = IOException.class)
 	public void testSSLClientFailure() throws Exception {
 		// SSL client connected to non-ssl server
-		uploadJarFile(BLOB_SERVER, sslClientConfig);
+		uploadJarFile(blobServer, sslClientConfig);
 	}
 
 	/**
@@ -135,7 +135,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	@Test(expected = IOException.class)
 	public void testSSLClientFailure2() throws Exception {
 		// SSL client connected to non-ssl server
-		uploadJarFile(BLOB_NON_SSL_SERVER, sslClientConfig);
+		uploadJarFile(blobNonSslServer, sslClientConfig);
 	}
 
 	/**
@@ -144,7 +144,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	@Test(expected = IOException.class)
 	public void testSSLServerFailure() throws Exception {
 		// Non-SSL client connected to ssl server
-		uploadJarFile(BLOB_SSL_SERVER, clientConfig);
+		uploadJarFile(blobSslServer, clientConfig);
 	}
 
 	/**
@@ -153,7 +153,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	@Test(expected = IOException.class)
 	public void testSSLServerFailure2() throws Exception {
 		// Non-SSL client connected to ssl server
-		uploadJarFile(BLOB_SSL_SERVER, nonSslClientConfig);
+		uploadJarFile(blobSslServer, nonSslClientConfig);
 	}
 
 	/**
@@ -161,7 +161,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@Test
 	public void testNonSSLConnection() throws Exception {
-		uploadJarFile(BLOB_SERVER, clientConfig);
+		uploadJarFile(blobServer, clientConfig);
 	}
 
 	/**
@@ -169,7 +169,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@Test
 	public void testNonSSLConnection2() throws Exception {
-		uploadJarFile(BLOB_SERVER, nonSslClientConfig);
+		uploadJarFile(blobServer, nonSslClientConfig);
 	}
 
 	/**
@@ -177,7 +177,7 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@Test
 	public void testNonSSLConnection3() throws Exception {
-		uploadJarFile(BLOB_NON_SSL_SERVER, clientConfig);
+		uploadJarFile(blobNonSslServer, clientConfig);
 	}
 
 	/**
@@ -185,6 +185,6 @@ public class BlobClientSslTest extends BlobClientTest {
 	 */
 	@Test
 	public void testNonSSLConnection4() throws Exception {
-		uploadJarFile(BLOB_NON_SSL_SERVER, nonSslClientConfig);
+		uploadJarFile(blobNonSslServer, nonSslClientConfig);
 	}
 }

flink-runtime/src/test/java/org/apache/flink/runtime/blob/BlobClientTest.java

@@ -62,7 +62,7 @@ public class BlobClientTest extends TestLogger {
 	private static final int TEST_BUFFER_SIZE = 17 * 1000;
 
 	/** The instance of the (non-ssl) BLOB server used during the tests. */
-	static BlobServer BLOB_SERVER;
+	static BlobServer blobServer;
 
 	/** The blob service (non-ssl) client configuration. */
 	static Configuration clientConfig;
@@ -79,8 +79,8 @@ public class BlobClientTest extends TestLogger {
 		config.setString(BlobServerOptions.STORAGE_DIRECTORY,
 			temporaryFolder.newFolder().getAbsolutePath());
 
-		BLOB_SERVER = new BlobServer(config, new VoidBlobStore());
-		BLOB_SERVER.start();
+		blobServer = new BlobServer(config, new VoidBlobStore());
+		blobServer.start();
 
 		clientConfig = new Configuration();
 	}
@@ -90,8 +90,8 @@ public class BlobClientTest extends TestLogger {
 	 */
 	@AfterClass
 	public static void stopServer() throws IOException {
-		if (BLOB_SERVER != null) {
-			BLOB_SERVER.close();
+		if (blobServer != null) {
+			blobServer.close();
 		}
 	}
 
@@ -319,7 +319,7 @@ public class BlobClientTest extends TestLogger {
 	}
 
 	protected BlobServer getBlobServer() {
-		return BLOB_SERVER;
+		return blobServer;
 	}
 
 	@Test

flink-runtime/src/test/java/org/apache/flink/runtime/blob/TestingFailingBlobServer.java

@@ -78,7 +78,7 @@ public class TestingFailingBlobServer extends BlobServer {
 				if (socket != null) {
 					try {
 						socket.close();
-					} catch(Throwable ignored) {}
+					} catch (Throwable ignored) {}
 				}
 			}
 		}

tools/maven/suppressions-runtime.xml

@@ -23,13 +23,6 @@ under the License.
 	"http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
 
 <suppressions>
-	<suppress
-		files="(.*)runtime[/\\]blob[/\\](.*)"
-		checks="NewlineAtEndOfFile|RegexpSingleline|TodoComment|RedundantImport|ImportOrder|RedundantModifier|JavadocMethod|JavadocParagraph|JavadocType|JavadocStyle|PackageName|TypeNameCheck|ConstantNameCheck|StaticVariableNameCheck|MemberNameCheck|MethodNameCheck|ParameterName|LocalFinalVariableName|LocalVariableName|LeftCurly|UpperEll|FallThrough|reliefPattern|SimplifyBooleanExpression|EmptyStatement|ModifierOrder|EmptyLineSeparator|WhitespaceAround|WhitespaceAfter|NoWhitespaceAfter|NoWhitespaceBefore|OperatorWrap|ParenPad"/>
-	<!--Only additional checks for test sources. Those checks were present in the "pre-strict" checkstyle but were not applied to test sources. We do not want to suppress them for sources directory-->
-	<suppress
-		files="(.*)test[/\\](.*)runtime[/\\]blob[/\\](.*)"
-		checks="AvoidStarImport|UnusedImport"/>
 	<suppress
 		files="(.*)runtime[/\\]checkpoint[/\\](.*)"
 		checks="NewlineAtEndOfFile|RegexpSingleline|TodoComment|RedundantImport|ImportOrder|RedundantModifier|JavadocMethod|JavadocParagraph|JavadocType|JavadocStyle|PackageName|TypeNameCheck|ConstantNameCheck|StaticVariableNameCheck|MemberNameCheck|MethodNameCheck|ParameterName|LocalFinalVariableName|LocalVariableName|LeftCurly|UpperEll|FallThrough|reliefPattern|SimplifyBooleanExpression|EmptyStatement|ModifierOrder|EmptyLineSeparator|WhitespaceAround|WhitespaceAfter|NoWhitespaceAfter|NoWhitespaceBefore|OperatorWrap|ParenPad"/>