Added the javadoc for openFile and openFileWithOptions method

Author: prince-cs

src/main/java/io/cdap/plugin/gcp/crypto/EncryptedFileSystem.java

@@ -48,6 +48,7 @@ public class EncryptedFileSystem extends FilterFileSystem {
   private static final String FS_SCHEME = CONF_PREFIX + "scheme";
   private static final String FS_IMPL = CONF_PREFIX + "impl";
   private static final String DECRYPTOR_IMPL = CONF_PREFIX + "decryptor.impl";
+  private static final int DEFAULT_BUFFER_SIZE = 4096;
 
   private static final Logger LOG = LoggerFactory.getLogger(EncryptedFileSystem.class);
 
@@ -109,6 +110,18 @@ public FSDataInputStream open(Path path, int bufferSize) throws IOException {
     return new FSDataInputStream(new SeekableByteChannelFSInputStream(decryptor.open(fs, path, bufferSize)));
   }
 
+  /**
+   * Opens a file asynchronously and returns a {@link FutureDataInputStreamBuilder}
+   * to build a {@link FSDataInputStream} for the specified {@link Path}.
+   *
+   * <p>This implementation returns a builder that constructs an input stream by using a decryptor
+   * to open the file through a {@link SeekableByteChannelFSInputStream}. The file is read
+   * with a buffer size of 4096 bytes.</p>
+   *
+   * @param path the {@link Path} of the file to open
+   * @return a {@link FutureDataInputStreamBuilder} that asynchronously builds a {@link FSDataInputStream}
+   * @throws UnsupportedOperationException if the operation is not supported
+   */
   @Override
   public FutureDataInputStreamBuilder openFile(Path path) throws UnsupportedOperationException {
     return new FutureDataInputStreamBuilder() {
@@ -118,7 +131,7 @@ public CompletableFuture<FSDataInputStream> build()
         return CompletableFuture.supplyAsync(() -> {
           try {
             return new FSDataInputStream(
-              new SeekableByteChannelFSInputStream(decryptor.open(fs, path, 4096)));
+              new SeekableByteChannelFSInputStream(decryptor.open(fs, path, DEFAULT_BUFFER_SIZE)));
           } catch (Exception e) {
             throw new CompletionException(e);
           }
@@ -127,26 +140,39 @@ public CompletableFuture<FSDataInputStream> build()
 
       @Override
       public FutureDataInputStreamBuilder opt(@NotNull String s, @NotNull String s1) {
-        return null;
+        return this;
       }
 
       @Override
       public FutureDataInputStreamBuilder opt(@NotNull String s, @NotNull String... strings) {
-        return null;
+        return this;
       }
 
       @Override
       public FutureDataInputStreamBuilder must(@NotNull String s, @NotNull String s1) {
-        return null;
+        return this;
       }
 
       @Override
       public FutureDataInputStreamBuilder must(@NotNull String s, @NotNull String... strings) {
-        return null;
+        return this;
       }
     };
   }
 
+  /**
+   * Opens a file asynchronously using the provided {@link Path}, and returns
+   * a {@link CompletableFuture} that supplies a {@link FSDataInputStream}.
+   *
+   * <p>This method uses a decryptor to open the file and wraps it in a {@link SeekableByteChannelFSInputStream}.
+   * It uses the buffer size specified in the {@code parameters}; if the buffer size is not greater than zero,
+   * a default of 4096 bytes is used.</p>
+   *
+   * @param path the {@link Path} to the file to open
+   * @param parameters the {@link OpenFileParameters} containing optional configuration, such as buffer size
+   * @return a {@link CompletableFuture} that will complete with the {@link FSDataInputStream}
+   * @throws CompletionException if an exception occurs during file opening
+   */
   @Override
   protected CompletableFuture<FSDataInputStream> openFileWithOptions(Path path, OpenFileParameters parameters) {
     return CompletableFuture.supplyAsync(() -> {