iHDFS-3282. Expose getFileLength API. Contributed by Uma Maheswara Rao G.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1327790 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/HdfsDataInputStream.java

@@ -0,0 +1,71 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.client;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.hdfs.DFSInputStream;
+import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
+import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
+
+/**
+ * The Hdfs implementation of {@link FSDataInputStream}.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public class HdfsDataInputStream extends FSDataInputStream {
+  public HdfsDataInputStream(DFSInputStream in) throws IOException {
+    super(in);
+  }
+
+  /**
+   * Get the datanode from which the stream is currently reading.
+   */
+  public DatanodeInfo getCurrentDatanode() {
+    return ((DFSInputStream) in).getCurrentDatanode();
+  }
+
+  /**
+   * Get the block containing the target position.
+   */
+  public ExtendedBlock getCurrentBlock() {
+    return ((DFSInputStream) in).getCurrentBlock();
+  }
+
+  /**
+   * Get the collection of blocks that has already been located.
+   */
+  public synchronized List<LocatedBlock> getAllBlocks() throws IOException {
+    return ((DFSInputStream) in).getAllBlocks();
+  }
+
+  /**
+   * Get the visible length of the file. It will include the length of the last
+   * block even if that is in UnderConstruction state.
+   * 
+   * @return The visible length of the file.
+   */
+  public long getVisibleLength() throws IOException {
+    return ((DFSInputStream) in).getFileLength();
+  }
+}