Better names

src/main/java/org/apache/commons/net/ftp/FTP.java

@@ -147,16 +147,15 @@ public class FTP extends SocketClient {
 
     /**
      * A constant used to indicate a file is to be transferred as FTP compressed data. All constants ending in <code>TRANSFER_MODE</code> are used to indicate
-     * file transfer modes.
+     * file transfer modes. Currently unused.
      */
     public static final int COMPRESSED_TRANSFER_MODE = 12;
 
     /**
-     * A constant used to indicate a file is to be transferred as FTP compressed
-     * data with MODE Z (zlib). All constants ending in <code>TRANSFER_MODE</code> are used to indicate
-     * file transfer modes.
+     * A constant used to indicate a file is to be transferred as FTP (un)compressing data in the "deflate" compression format. All constants ending in
+     * <code>TRANSFER_MODE</code> are used to indicate file transfer modes.
      */
-    public static final int COMPRESSED_MODE_Z_TRANSFER_MODE = 13;
+    public static final int DEFLATE_TRANSFER_MODE = 13;
 
     // We have to ensure that the protocol communication is in ASCII,
     // but we use ISO-8859-1 just in case 8-bit characters cross

src/main/java/org/apache/commons/net/ftp/FTPClient.java

@@ -446,8 +446,8 @@ private static Properties getOverrideProperties() {
      * Parse the pathname from a CWD reply.
      * <p>
      * According to <a href="http://www.ietf.org/rfc/rfc959.txt">RFC959</a>, it should be the same as for MKD i.e.
-     * {@code 257<space>"<directory-name>"[<space>commentary]} where any double-quotes in {@code <directory-name>} are doubled.
-     * Unlike MKD, the commentary is optional.
+     * {@code 257<space>"<directory-name>"[<space>commentary]} where any double-quotes in {@code <directory-name>} are doubled. Unlike MKD, the commentary is
+     * optional.
      * <p>
      * However, see NET-442 for an exception.
      *
@@ -713,7 +713,7 @@ protected Socket _openDataConnection_(final String command, final String arg) th
                     server.setSoTimeout(soTimeoutMillis);
                 }
 
-                socket = wrapSocketIfModeZisEnabled(server.accept());
+                socket = wrapOnDeflate(server.accept());
 
                 // Ensure the timeout is set before any commands are issued on the new socket
                 if (soTimeoutMillis >= 0) {
@@ -749,7 +749,7 @@ protected Socket _openDataConnection_(final String command, final String arg) th
                 _parsePassiveModeReply(_replyLines.get(0));
             }
 
-            socket = wrapSocketIfModeZisEnabled(_socketFactory_.createSocket());
+            socket = wrapOnDeflate(_socketFactory_.createSocket());
 
             if (receiveDataSocketBufferSize > 0) {
                 socket.setReceiveBufferSize(receiveDataSocketBufferSize);
@@ -2384,7 +2384,7 @@ public String[] listNames(final String pathname) throws IOException {
     /**
      * Login to the FTP server using the provided user and password.
      *
-     * @param user The user name to login under.
+     * @param user     The user name to login under.
      * @param password The password to use.
      * @return True if successfully completed, false if not.
      * @throws FTPConnectionClosedException If the FTP server prematurely closes the connection as a result of the client being idle or some other reason
@@ -2413,7 +2413,7 @@ public boolean login(final String user, final String password) throws IOExceptio
      * Login to the FTP server using the provided username, password, and account. If no account is required by the server, only the username and password, the
      * account information is not used.
      *
-     * @param user The user name to login under.
+     * @param user     The user name to login under.
      * @param password The password to use.
      * @param account  The account to use.
      * @return True if successfully completed, false if not.
@@ -3419,10 +3419,8 @@ public boolean structureMount(final String pathname) throws IOException {
         return FTPReply.isPositiveCompletion(smnt(pathname));
     }
 
-    private Socket wrapSocketIfModeZisEnabled(final Socket plainSocket) {
-        if (fileTransferMode == COMPRESSED_MODE_Z_TRANSFER_MODE) {
-            return DeflateSocket.wrap(plainSocket);
-        }
-        return plainSocket;
+    @SuppressWarnings("resource")
+    private Socket wrapOnDeflate(final Socket plainSocket) {
+        return fileTransferMode == DEFLATE_TRANSFER_MODE ? DeflateSocket.wrap(plainSocket) : plainSocket;
     }
 }

src/test/java/org/apache/commons/net/ftp/FTPClientDeflateTest.java

@@ -20,7 +20,7 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.nio.file.Files.readAllBytes;
 import static org.apache.commons.io.FileUtils.deleteDirectory;
-import static org.apache.commons.net.ftp.FTP.COMPRESSED_MODE_Z_TRANSFER_MODE;
+import static org.apache.commons.net.ftp.FTP.DEFLATE_TRANSFER_MODE;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -139,7 +139,7 @@ public void testRetrievingFiles() throws Exception {
             try {
                 client.connect("localhost", port);
                 client.login(user, password);
-                assertTrue("Mode Z successfully activated", client.setFileTransferMode(COMPRESSED_MODE_Z_TRANSFER_MODE));
+                assertTrue("Mode Z successfully activated", client.setFileTransferMode(DEFLATE_TRANSFER_MODE));
 
                 final FTPFile[] files = client.listFiles();
                 assertEquals("Only single file in home directory", 1, files.length);
@@ -160,7 +160,7 @@ public void testStoringFiles() throws Exception {
             try {
                 client.connect("localhost", port);
                 client.login(user, password);
-                assertTrue("Mode Z successfully activated", client.setFileTransferMode(COMPRESSED_MODE_Z_TRANSFER_MODE));
+                assertTrue("Mode Z successfully activated", client.setFileTransferMode(DEFLATE_TRANSFER_MODE));
 
                 final FTPFile[] filesBeforeUpload = client.listFiles();
                 assertEquals("No files in home directory before upload", 0, filesBeforeUpload.length);