HDFS-14595. HDFS-11848 breaks API compatibility. Contributed by Siyao Meng.

Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>
Reviewed-by: Ayush Saxena <ayushsaxena@apache.org>

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

@@ -3380,6 +3380,12 @@ public class DistributedFileSystem extends FileSystem
     return dfs.listOpenFiles();
   }
 
+  @Deprecated
+  public RemoteIterator<OpenFileEntry> listOpenFiles(
+      EnumSet<OpenFilesType> openFilesTypes) throws IOException {
+    return dfs.listOpenFiles(openFilesTypes);
+  }
+
   public RemoteIterator<OpenFileEntry> listOpenFiles(
       EnumSet<OpenFilesType> openFilesTypes, String path) throws IOException {
     return dfs.listOpenFiles(openFilesTypes, path);

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

@@ -626,6 +626,12 @@ public class HdfsAdmin {
     return dfs.listOpenFiles();
   }
 
+  @Deprecated
+  public RemoteIterator<OpenFileEntry> listOpenFiles(
+      EnumSet<OpenFilesType> openFilesTypes) throws IOException {
+    return dfs.listOpenFiles(openFilesTypes);
+  }
+
   public RemoteIterator<OpenFileEntry> listOpenFiles(
       EnumSet<OpenFilesType> openFilesTypes, String path) throws IOException {
     return dfs.listOpenFiles(openFilesTypes, path);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDistributedFileSystem.java

@@ -94,6 +94,8 @@ import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.StoragePolicySatisfierMode;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
+import org.apache.hadoop.hdfs.protocol.OpenFileEntry;
+import org.apache.hadoop.hdfs.protocol.OpenFilesIterator;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
@@ -194,8 +196,10 @@ public class TestDistributedFileSystem {
    * Tests DFSClient.close throws no ConcurrentModificationException if 
    * multiple files are open.
    * Also tests that any cached sockets are closed. (HDFS-3359)
+   * Also tests deprecated listOpenFiles(EnumSet<>). (HDFS-14595)
    */
   @Test
+  @SuppressWarnings("deprecation") // call to listOpenFiles(EnumSet<>)
   public void testDFSClose() throws Exception {
     Configuration conf = getTestConfiguration();
     MiniDFSCluster cluster = null;
@@ -207,6 +211,19 @@ public class TestDistributedFileSystem {
       fileSys.create(new Path("/test/dfsclose/file-0"));
       fileSys.create(new Path("/test/dfsclose/file-1"));
 
+      // Test listOpenFiles(EnumSet<>)
+      List<OpenFilesIterator.OpenFilesType> types = new ArrayList<>();
+      types.add(OpenFilesIterator.OpenFilesType.ALL_OPEN_FILES);
+      RemoteIterator<OpenFileEntry> listOpenFiles =
+          fileSys.listOpenFiles(EnumSet.copyOf(types));
+      assertTrue("Two files should be open", listOpenFiles.hasNext());
+      int countOpenFiles = 0;
+      while (listOpenFiles.hasNext()) {
+        listOpenFiles.next();
+        ++countOpenFiles;
+      }
+      assertEquals("Mismatch of open files count", 2, countOpenFiles);
+
       // create another file, close it, and read it, so
       // the client gets a socket in its SocketCache
       Path p = new Path("/non-empty-file");

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestHdfsAdmin.java

@@ -233,6 +233,9 @@ public class TestHdfsAdmin {
       closedFileSet.add(filePath);
     }
     verifyOpenFiles(closedFileSet, openFileMap);
+    // Verify again with the old listOpenFiles(EnumSet<>) API
+    // Just to verify old API's validity
+    verifyOpenFilesOld(closedFileSet, openFileMap);
 
     openFileMap.putAll(
         DFSTestUtil.createOpenFiles(fs, "open-file-1", numOpenFiles));
@@ -252,13 +255,10 @@ public class TestHdfsAdmin {
     }
   }
 
-  private void verifyOpenFiles(HashSet<Path> closedFiles,
-      HashMap<Path, FSDataOutputStream> openFileMap) throws IOException {
-    HdfsAdmin hdfsAdmin = new HdfsAdmin(FileSystem.getDefaultUri(conf), conf);
-    HashSet<Path> openFiles = new HashSet<>(openFileMap.keySet());
-    RemoteIterator<OpenFileEntry> openFilesRemoteItr =
-        hdfsAdmin.listOpenFiles(EnumSet.of(OpenFilesType.ALL_OPEN_FILES),
-            OpenFilesIterator.FILTER_PATH_DEFAULT);
+  private void verifyOpenFilesHelper(
+      RemoteIterator<OpenFileEntry> openFilesRemoteItr,
+      HashSet<Path> closedFiles,
+      HashSet<Path> openFiles) throws IOException {
     while (openFilesRemoteItr.hasNext()) {
       String filePath = openFilesRemoteItr.next().getFilePath();
       assertFalse(filePath + " should not be listed under open files!",
@@ -266,6 +266,30 @@ public class TestHdfsAdmin {
       assertTrue(filePath + " is not listed under open files!",
           openFiles.remove(new Path(filePath)));
     }
+  }
+
+  private void verifyOpenFiles(HashSet<Path> closedFiles,
+      HashMap<Path, FSDataOutputStream> openFileMap) throws IOException {
+    HdfsAdmin hdfsAdmin = new HdfsAdmin(FileSystem.getDefaultUri(conf), conf);
+    HashSet<Path> openFiles = new HashSet<>(openFileMap.keySet());
+    RemoteIterator<OpenFileEntry> openFilesRemoteItr =
+        hdfsAdmin.listOpenFiles(EnumSet.of(OpenFilesType.ALL_OPEN_FILES),
+            OpenFilesIterator.FILTER_PATH_DEFAULT);
+    verifyOpenFilesHelper(openFilesRemoteItr, closedFiles, openFiles);
+    assertTrue("Not all open files are listed!", openFiles.isEmpty());
+  }
+
+  /**
+   * Using deprecated HdfsAdmin#listOpenFiles(EnumSet<>) to verify open files.
+   */
+  @SuppressWarnings("deprecation") // call to listOpenFiles(EnumSet<>)
+  private void verifyOpenFilesOld(HashSet<Path> closedFiles,
+      HashMap<Path, FSDataOutputStream> openFileMap) throws IOException {
+    HdfsAdmin hdfsAdmin = new HdfsAdmin(FileSystem.getDefaultUri(conf), conf);
+    HashSet<Path> openFiles = new HashSet<>(openFileMap.keySet());
+    RemoteIterator<OpenFileEntry> openFilesRemoteItr =
+        hdfsAdmin.listOpenFiles(EnumSet.of(OpenFilesType.ALL_OPEN_FILES));
+    verifyOpenFilesHelper(openFilesRemoteItr, closedFiles, openFiles);
     assertTrue("Not all open files are listed!", openFiles.isEmpty());
   }
 }