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	SequenceFiles 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 WritableComparables.
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