Package org.apache.hadoop.hdfs.server.namenode

Class NullBlockAliasMap

java.lang.Object
org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap<FileRegion>
org.apache.hadoop.hdfs.server.namenode.NullBlockAliasMap
@Public @Unstable public class NullBlockAliasMap extends BlockAliasMap<FileRegion>
Null sink for region information emitted from FSImage.

  • Nested Class Summary

    Nested classes/interfaces inherited from class org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap

    org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.ImmutableIterator, org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<U extends BlockAlias>, org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer<U extends BlockAlias>

  • Constructor Summary

    Constructors
    Constructor
    Description
    NullBlockAliasMap()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
     
    org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<FileRegion>
    getReader(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader.Options opts, String blockPoolID)
    Returns a reader to the alias map.
    org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer
    getWriter(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer.Options opts, String blockPoolID)
    Returns the writer for the alias map.
    void
    refresh()
    Refresh the alias map.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • NullBlockAliasMap

      public NullBlockAliasMap()

  • Method Details

    • getReader

      public org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader<FileRegion> getReader(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Reader.Options opts, String blockPoolID) throws IOException
      Description copied from class: BlockAliasMap
      Returns a reader to the alias map.
      Specified by:
      getReader in class BlockAliasMap<FileRegion>
      Parameters:
      opts - reader options
      blockPoolID - block pool id to use
      Returns:
      BlockAliasMap.Reader to the alias map. If a Reader for the blockPoolID cannot be created, this will return null.
      Throws:
      IOException

    • getWriter

      public org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer getWriter(org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap.Writer.Options opts, String blockPoolID) throws IOException
      Description copied from class: BlockAliasMap
      Returns the writer for the alias map.
      Specified by:
      getWriter in class BlockAliasMap<FileRegion>
      Parameters:
      opts - writer options.
      blockPoolID - block pool id to use
      Returns:
      BlockAliasMap.Writer to the alias map.
      Throws:
      IOException

    • refresh

      public void refresh() throws IOException
      Description copied from class: BlockAliasMap
      Refresh the alias map.
      Specified by:
      refresh in class BlockAliasMap<FileRegion>
      Throws:
      IOException

    • close

      public void close() throws IOException
      Specified by:
      close in class BlockAliasMap<FileRegion>
      Throws:
      IOException