org.apache.hadoop.io (Apache Hadoop Main 3.5.0 API)
Description: declaration: package: org.apache.hadoop.io

# Package org.apache.hadoop.io

package org.apache.hadoop.io
Generic i/o code for use when reading and writing data to the network, to databases, and to files.

- Related Packages
  Package
  Description
  org.apache.hadoop
  org.apache.hadoop.io.compress
  org.apache.hadoop.io.erasurecode
  org.apache.hadoop.io.serializer
  This package provides a mechanism for using different serialization frameworks in Hadoop.
  org.apache.hadoop.io.wrappedio
  Support for dynamic access to filesystem operations which are not available in older hadoop releases.
- Class
  Description
  AbstractMapWritable
  Abstract base class for MapWritable and SortedMapWritable Unlike org.apache.nutch.crawl.MapWritable, this class allows creation of MapWritable<Writable, MapWritable> so the CLASS_TO_ID and ID_TO_CLASS maps travel with the class instead of being static.
  ArrayFile
  A dense file-based mapping from integers to values.
  org.apache.hadoop.io.ArrayFile.Reader
  Provide access to an existing array file.
  org.apache.hadoop.io.ArrayFile.Writer
  Write a new array file.
  ArrayPrimitiveWritable
  This is a wrapper class.
  ArrayWritable
  A Writable for arrays containing instances of a class.
  BinaryComparable
  Interface supported by `WritableComparable` types supporting ordering/permutation by a representative set of bytes.
  BloomMapFile
  This class extends `MapFile` and provides very much the same functionality.
  org.apache.hadoop.io.BloomMapFile.Reader
  org.apache.hadoop.io.BloomMapFile.Writer
  BooleanWritable
  A WritableComparable for booleans.
  org.apache.hadoop.io.BooleanWritable.Comparator
  A Comparator optimized for BooleanWritable.
  org.apache.hadoop.io.BoundedByteArrayOutputStream
  A byte array backed output stream with a limit.
  ByteBufferPool
  BytesWritable
  A byte sequence that is usable as a key or value.
  org.apache.hadoop.io.BytesWritable.Comparator
  A Comparator optimized for BytesWritable.
  ByteWritable
  A WritableComparable for a single byte.
  org.apache.hadoop.io.ByteWritable.Comparator
  A Comparator optimized for ByteWritable.
  Closeable
  Deprecated.
  use java.io.Closeable
  CompressedWritable
  A base-class for Writables which store themselves compressed and lazily inflate on field access.
  org.apache.hadoop.io.DataInputBuffer
  A reusable `DataInput` implementation that reads from an in-memory buffer.
  org.apache.hadoop.io.DataInputByteBuffer
  org.apache.hadoop.io.DataOutputBuffer
  A reusable `DataOutput` implementation that writes to an in-memory buffer.
  DataOutputOutputStream
  OutputStream implementation that wraps a DataOutput.
  DefaultStringifier<T>
  DefaultStringifier is the default implementation of the `Stringifier` interface which stringifies the objects using base64 encoding of the serialized version of the objects.
  DoubleWritable
  Writable for Double values.
  org.apache.hadoop.io.DoubleWritable.Comparator
  A Comparator optimized for DoubleWritable.
  ElasticByteBufferPool
  This is a simple ByteBufferPool which just creates ByteBuffers as needed.
  org.apache.hadoop.io.ElasticByteBufferPool.Key
  EnumSetWritable<E extends Enum<E>>
  A Writable wrapper for EnumSet.
  FloatWritable
  A WritableComparable for floats.
  org.apache.hadoop.io.FloatWritable.Comparator
  A Comparator optimized for FloatWritable.
  GenericWritable
  A wrapper for Writable instances.
  org.apache.hadoop.io.InputBuffer
  A reusable `InputStream` implementation that reads from an in-memory buffer.
  IntWritable
  A WritableComparable for ints.
  org.apache.hadoop.io.IntWritable.Comparator
  A Comparator optimized for IntWritable.
  IOUtils
  An utility class for I/O related functionality.
  org.apache.hadoop.io.IOUtils.NullOutputStream
  The /dev/null of OutputStreams.
  LongWritable
  A WritableComparable for longs.
  org.apache.hadoop.io.LongWritable.Comparator
  A Comparator optimized for LongWritable.
  org.apache.hadoop.io.LongWritable.DecreasingComparator
  A decreasing Comparator optimized for LongWritable.
  MapFile
  A file-based map from keys to values.
  org.apache.hadoop.io.MapFile.Merger
  Class to merge multiple MapFiles of same Key and Value types to one MapFile
  org.apache.hadoop.io.MapFile.Reader
  Provide access to an existing map.
  org.apache.hadoop.io.MapFile.Reader.Option
  org.apache.hadoop.io.MapFile.Writer
  Writes a new map.
  org.apache.hadoop.io.MapFile.Writer.Option
  MapWritable
  A Writable Map.
  MD5Hash
  A Writable for MD5 hash values.
  org.apache.hadoop.io.MD5Hash.Comparator
  A WritableComparator optimized for MD5Hash keys.
  MultipleIOException
  Encapsulate a list of `IOException` into an `IOException`
  org.apache.hadoop.io.MultipleIOException.Builder
  Build an `IOException` using `MultipleIOException` if there are more than one.
  NullWritable
  Singleton Writable with no data.
  org.apache.hadoop.io.NullWritable.Comparator
  A Comparator "optimized" for NullWritable.
  ObjectWritable
  A polymorphic Writable that writes an instance with it's class name.
  org.apache.hadoop.io.OutputBuffer
  A reusable `OutputStream` implementation that writes to an in-memory buffer.
  RawComparator<T>
  A `Comparator` that operates directly on byte representations of objects.
  org.apache.hadoop.io.ReadaheadPool
  Manages a pool of threads which can issue readahead requests on file descriptors.
  org.apache.hadoop.io.ReadaheadPool.ReadaheadRequest
  An outstanding readahead request that has been submitted to the pool.
  org.apache.hadoop.io.SecureIOUtils
  This class provides secure APIs for opening and creating files on the local disk.
  org.apache.hadoop.io.SecureIOUtils.AlreadyExistsException
  Signals that an attempt to create a file at a given pathname has failed because another file already existed at that path.
  SequenceFile
  `SequenceFile`s are flat files consisting of binary key/value pairs.
  SequenceFile.CompressionType
  The compression type used to compress key/value pairs in the `SequenceFile`.
  org.apache.hadoop.io.SequenceFile.Metadata
  The class encapsulating with the metadata of a file.
  org.apache.hadoop.io.SequenceFile.Reader
  Reads key/value pairs from a sequence-format file.
  org.apache.hadoop.io.SequenceFile.Reader.Option
  A tag interface for all of the Reader options
  org.apache.hadoop.io.SequenceFile.Sorter
  Sorts key/value pairs in a sequence-format file.
  org.apache.hadoop.io.SequenceFile.Sorter.RawKeyValueIterator
  The interface to iterate over raw keys/values of SequenceFiles.
  org.apache.hadoop.io.SequenceFile.ValueBytes
  The interface to 'raw' values of SequenceFiles.
  org.apache.hadoop.io.SequenceFile.Writer
  Write key/value pairs to a sequence-format file.
  org.apache.hadoop.io.SequenceFile.Writer.Option
  SetFile
  A file-based set of keys.
  org.apache.hadoop.io.SetFile.Reader
  Provide access to an existing set file.
  org.apache.hadoop.io.SetFile.Writer
  Write a new set file.
  ShortWritable
  A WritableComparable for shorts.
  org.apache.hadoop.io.ShortWritable.Comparator
  A Comparator optimized for ShortWritable.
  Sizes
  Sizes of binary values and other some common sizes.
  SortedMapWritable<K extends WritableComparable<? super K>>
  A Writable SortedMap.
  Stringifier<T>
  Stringifier interface offers two methods to convert an object to a string representation and restore the object given its string representation.
  Text
  This class stores text using standard UTF8 encoding.
  org.apache.hadoop.io.Text.Comparator
  A WritableComparator optimized for Text keys.
  TwoDArrayWritable
  A Writable for 2D arrays containing a matrix of instances of a class.
  org.apache.hadoop.io.UTF8
  Deprecated.
  replaced by Text
  org.apache.hadoop.io.UTF8.Comparator
  A WritableComparator optimized for UTF8 keys.
  VersionedWritable
  A base class for Writables that provides version checking.
  VersionMismatchException
  Thrown by `VersionedWritable.readFields(DataInput)` when the version of an object being read does not match the current implementation version as returned by `VersionedWritable.getVersion()`.
  VIntWritable
  A WritableComparable for integer values stored in variable-length format.
  VLongWritable
  A WritableComparable for longs in a variable-length format.
  org.apache.hadoop.io.WeakReferencedElasticByteBufferPool
  Buffer pool implementation which uses weak references to store buffers in the pool, such that they are garbage collected when there are no references to the buffer during a gc run.
  Writable
  A serializable object which implements a simple, efficient, serialization protocol, based on `DataInput` and `DataOutput`.
  WritableComparable<T>
  A `Writable` which is also `Comparable`.
  WritableComparator
  A Comparator for `WritableComparable`s.
  WritableFactories
  Factories for non-public writables.
  WritableFactory
  A factory for a class of Writable.
  org.apache.hadoop.io.WritableName
  Utility to permit renaming of Writable implementation classes without invalidiating files that contain their class name.
  WritableUtils