HADOOP-16830. Add public IOStatistics API.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java

@@ -46,9 +46,13 @@
 import org.apache.hadoop.fs.Seekable;
 import org.apache.hadoop.fs.StreamCapabilities;
 import org.apache.hadoop.fs.StreamCapabilitiesPolicy;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
 import org.apache.hadoop.io.ByteBufferPool;
 import org.apache.hadoop.util.StringUtils;
 
+import static org.apache.hadoop.fs.statistics.IOStatisticsSupport.retrieveIOStatistics;
+
 /**
  * CryptoInputStream decrypts data. It is not thread-safe. AES CTR mode is
  * required in order to ensure that the plain text and cipher text have a 1:1
@@ -66,7 +70,7 @@ public class CryptoInputStream extends FilterInputStream implements
     Seekable, PositionedReadable, ByteBufferReadable, HasFileDescriptor, 
     CanSetDropBehind, CanSetReadahead, HasEnhancedByteBufferAccess, 
     ReadableByteChannel, CanUnbuffer, StreamCapabilities,
-    ByteBufferPositionedReadable {
+    ByteBufferPositionedReadable, IOStatisticsSource {
   private final byte[] oneByteBuf = new byte[1];
   private final CryptoCodec codec;
   private final Decryptor decryptor;
@@ -867,8 +871,16 @@ public boolean hasCapability(String capability) {
           + " does not expose its stream capabilities.");
       }
       return ((StreamCapabilities) in).hasCapability(capability);
+    case StreamCapabilities.IOSTATISTICS:
+      return (in instanceof StreamCapabilities)
+          && ((StreamCapabilities) in).hasCapability(capability);
     default:
       return false;
     }
   }
+
+  @Override
+  public IOStatistics getIOStatistics() {
+    return retrieveIOStatistics(in);
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoOutputStream.java

@@ -28,9 +28,13 @@
 import org.apache.hadoop.fs.CanSetDropBehind;
 import org.apache.hadoop.fs.StreamCapabilities;
 import org.apache.hadoop.fs.Syncable;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
 
 import com.google.common.base.Preconditions;
 
+import static org.apache.hadoop.fs.statistics.IOStatisticsSupport.retrieveIOStatistics;
+
 /**
  * CryptoOutputStream encrypts data. It is not thread-safe. AES CTR mode is
  * required in order to ensure that the plain text and cipher text have a 1:1
@@ -48,7 +52,7 @@
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class CryptoOutputStream extends FilterOutputStream implements 
-    Syncable, CanSetDropBehind, StreamCapabilities {
+    Syncable, CanSetDropBehind, StreamCapabilities, IOStatisticsSource {
   private final byte[] oneByteBuf = new byte[1];
   private final CryptoCodec codec;
   private final Encryptor encryptor;
@@ -313,4 +317,9 @@ public boolean hasCapability(String capability) {
     }
     return false;
   }
+
+  @Override
+  public IOStatistics getIOStatistics() {
+    return retrieveIOStatistics(out);
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/BufferedFSInputStream.java

@@ -24,6 +24,10 @@
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
+
+import static org.apache.hadoop.fs.statistics.IOStatisticsSupport.retrieveIOStatistics;
 
 
 /**
@@ -33,7 +37,8 @@
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 public class BufferedFSInputStream extends BufferedInputStream
-implements Seekable, PositionedReadable, HasFileDescriptor {
+    implements Seekable, PositionedReadable, HasFileDescriptor,
+    IOStatisticsSource, StreamCapabilities {
   /**
    * Creates a <code>BufferedFSInputStream</code>
    * with the specified buffer size,
@@ -126,4 +131,26 @@ public FileDescriptor getFileDescriptor() throws IOException {
       return null;
     }
   }
+
+  /**
+   * If the inner stream supports {@link StreamCapabilities},
+   * forward the probe to it.
+   * Otherwise: return false.
+   *
+   * @param capability string to query the stream support for.
+   * @return true if a capability is known to be supported.
+   */
+  @Override
+  public boolean hasCapability(final String capability) {
+    if (in instanceof StreamCapabilities) {
+      return ((StreamCapabilities) in).hasCapability(capability);
+    } else {
+      return false;
+    }
+  }
+
+  @Override
+  public IOStatistics getIOStatistics() {
+    return retrieveIOStatistics(in);
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFileSystem.java

@@ -38,6 +38,9 @@
 import org.apache.hadoop.fs.impl.OpenFileParameters;
 import org.apache.hadoop.fs.permission.AclEntry;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
+import org.apache.hadoop.fs.statistics.IOStatisticsSupport;
 import org.apache.hadoop.util.DataChecksum;
 import org.apache.hadoop.util.LambdaUtils;
 import org.apache.hadoop.util.Progressable;
@@ -134,7 +137,8 @@ private int getSumBufferSize(int bytesPerSum, int bufferSize) {
    * For open()'s FSInputStream
    * It verifies that data matches checksums.
    *******************************************************/
-  private static class ChecksumFSInputChecker extends FSInputChecker {
+  private static class ChecksumFSInputChecker extends FSInputChecker implements
+      IOStatisticsSource {
     private ChecksumFileSystem fs;
     private FSDataInputStream datas;
     private FSDataInputStream sums;
@@ -270,6 +274,17 @@ protected int readChunk(long pos, byte[] buf, int offset, int len,
       }
       return nread;
     }
+
+    /**
+     * Get the IO Statistics of the nested stream, falling back to
+     * null if the stream does not implement the interface
+     * {@link IOStatisticsSource}.
+     * @return an IOStatistics instance or null
+     */
+    @Override
+    public IOStatistics getIOStatistics() {
+      return IOStatisticsSupport.retrieveIOStatistics(datas);
+    }
   }
 
   private static class FSDataBoundedInputStream extends FSDataInputStream {
@@ -395,7 +410,8 @@ public static long getChecksumLength(long size, int bytesPerSum) {
 
   /** This class provides an output stream for a checksummed file.
    * It generates checksums for data. */
-  private static class ChecksumFSOutputSummer extends FSOutputSummer {
+  private static class ChecksumFSOutputSummer extends FSOutputSummer
+      implements IOStatisticsSource, StreamCapabilities {
     private FSDataOutputStream datas;    
     private FSDataOutputStream sums;
     private static final float CHKSUM_AS_FRACTION = 0.01f;
@@ -449,6 +465,28 @@ protected void checkClosed() throws IOException {
         throw new ClosedChannelException();
       }
     }
+
+    /**
+     * Get the IO Statistics of the nested stream, falling back to
+     * null if the stream does not implement the interface
+     * {@link IOStatisticsSource}.
+     * @return an IOStatistics instance or null
+     */
+    @Override
+    public IOStatistics getIOStatistics() {
+      return IOStatisticsSupport.retrieveIOStatistics(datas);
+    }
+
+    /**
+     * Probe the inner stream for a capability.
+     *
+     * @param capability string to query the stream support for.
+     * @return true if a capability is known to be supported.
+     */
+    @Override
+    public boolean hasCapability(final String capability) {
+      return datas.hasCapability(capability);
+    }
   }
 
   @Override

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java

@@ -29,6 +29,9 @@
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
+import org.apache.hadoop.fs.statistics.IOStatisticsSupport;
 import org.apache.hadoop.io.ByteBufferPool;
 import org.apache.hadoop.util.IdentityHashStore;
 
@@ -40,7 +43,7 @@ public class FSDataInputStream extends DataInputStream
     implements Seekable, PositionedReadable, 
       ByteBufferReadable, HasFileDescriptor, CanSetDropBehind, CanSetReadahead,
       HasEnhancedByteBufferAccess, CanUnbuffer, StreamCapabilities,
-      ByteBufferPositionedReadable {
+      ByteBufferPositionedReadable, IOStatisticsSource {
   /**
    * Map ByteBuffers that we have handed out to readers to ByteBufferPool 
    * objects
@@ -267,4 +270,15 @@ public void readFully(long position, ByteBuffer buf) throws IOException {
               "unsupported by " + in.getClass().getCanonicalName());
     }
   }
+
+  /**
+   * Get the IO Statistics of the nested stream, falling back to
+   * null if the stream does not implement the interface
+   * {@link IOStatisticsSource}.
+   * @return an IOStatistics instance or null
+   */
+  @Override
+  public IOStatistics getIOStatistics() {
+    return IOStatisticsSupport.retrieveIOStatistics(in);
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataOutputStream.java

@@ -24,13 +24,17 @@
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.statistics.IOStatistics;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
+import org.apache.hadoop.fs.statistics.IOStatisticsSupport;
 
 /** Utility that wraps a {@link OutputStream} in a {@link DataOutputStream}.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Stable
 public class FSDataOutputStream extends DataOutputStream
-    implements Syncable, CanSetDropBehind, StreamCapabilities {
+    implements Syncable, CanSetDropBehind, StreamCapabilities,
+      IOStatisticsSource {
   private final OutputStream wrappedStream;
 
   private static class PositionCache extends FilterOutputStream {
@@ -155,4 +159,15 @@ public void setDropBehind(Boolean dropBehind) throws IOException {
           "not support setting the drop-behind caching setting.");
     }
   }
+
+  /**
+   * Get the IO Statistics of the nested stream, falling back to
+   * empty statistics if the stream does not implement the interface
+   * {@link IOStatisticsSource}.
+   * @return an IOStatistics instance.
+   */
+  @Override
+  public IOStatistics getIOStatistics() {
+    return IOStatisticsSupport.retrieveIOStatistics(wrappedStream);
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSInputStream.java

@@ -24,6 +24,9 @@
 import com.google.common.base.Preconditions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.statistics.IOStatisticsLogging;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -134,4 +137,23 @@ public void readFully(long position, byte[] buffer)
     throws IOException {
     readFully(position, buffer, 0, buffer.length);
   }
+
+  /**
+   * toString method returns the superclass toString, but if the subclass
+   * implements {@link IOStatisticsSource} then those statistics are
+   * extracted and included in the output.
+   * That is: statistics of subclasses are automatically reported.
+   * @return a string value.
+   */
+  @Override
+  public String toString() {
+    final StringBuilder sb = new StringBuilder(super.toString());
+    sb.append('{');
+    if (this instanceof IOStatisticsSource) {
+      sb.append(IOStatisticsLogging.ioStatisticsSourceToString(
+          (IOStatisticsSource) this));
+    }
+    sb.append('}');
+    return sb.toString();
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/MultipartUploader.java

@@ -26,14 +26,20 @@
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.statistics.IOStatisticsSource;
 
 /**
  * MultipartUploader is an interface for copying files multipart and across
  * multiple nodes.
+ * <p></p>
+ * The interface extends {@link IOStatisticsSource} so that there is no
+ * need to cast an instance to see if is a source of statistics.
+ * However, implementations MAY return null for their actual statistics.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Unstable
-public interface MultipartUploader extends Closeable {
+public interface MultipartUploader extends Closeable,
+    IOStatisticsSource {
 
 
   /**