Package org.apache.hadoop.io

Generic i/o code for use when reading and writing data to the network, to databases, and to files.

See:
Description

Interface Summary

Closeable	That which can be closed.
SequenceFile.Sorter.RawKeyValueIterator	The interface to iterate over raw keys/values of SequenceFiles.
SequenceFile.ValueBytes	The interface to 'raw' values of SequenceFiles.
Writable	A simple, efficient, serialization protocol, based on DataInput and DataOutput.
WritableComparable	An interface which extends both Writable and Comparable.
WritableFactory	A factory for a class of Writable.

Class Summary

ArrayFile	A dense file-based mapping from integers to values.
ArrayFile.Reader	Provide access to an existing array file.
ArrayFile.Writer	Write a new array file.
ArrayWritable	A Writable for arrays containing instances of a class.
BooleanWritable	A WritableComparable for booleans.
BooleanWritable.Comparator	A Comparator optimized for BooleanWritable.
BytesWritable	A byte sequence that is usable as a key or value.
BytesWritable.Comparator	A Comparator optimized for BytesWritable.
CompressedWritable	A base-class for Writables which store themselves compressed and lazily inflate on field access.
DataInputBuffer	A reusable DataInput implementation that reads from an in-memory buffer.
DataOutputBuffer	A reusable DataOutput implementation that writes to an in-memory buffer.
FloatWritable	A WritableComparable for floats.
FloatWritable.Comparator	A Comparator optimized for FloatWritable.
GenericWritable	A wrapper for Writable instances.
IntWritable	A WritableComparable for ints.
IntWritable.Comparator	A Comparator optimized for IntWritable.
LongWritable	A WritableComparable for longs.
LongWritable.Comparator	A Comparator optimized for LongWritable.
LongWritable.DecreasingComparator	A decreasing Comparator optimized for LongWritable.
MapFile	A file-based map from keys to values.
MapFile.Reader	Provide access to an existing map.
MapFile.Writer	Writes a new map.
MD5Hash	A Writable for MD5 hash values.
MD5Hash.Comparator	A WritableComparator optimized for MD5Hash keys.
NullWritable	Singleton Writable with no data.
ObjectWritable	A polymorphic Writable that writes an instance with it's class name.
SequenceFile	Support for flat files of binary key/value pairs.
SequenceFile.Metadata	The class encapsulating with the metadata of a file.
SequenceFile.Reader	Reads key/value pairs from a sequence-format file.
SequenceFile.Sorter	Sorts key/value pairs in a sequence-format file.
SequenceFile.Writer	Write key/value pairs to a sequence-format file.
SetFile	A file-based set of keys.
SetFile.Reader	Provide access to an existing set file.
SetFile.Writer	Deprecated. pass a Configuration too
Text	This class stores text using standard UTF8 encoding.
Text.Comparator	A WritableComparator optimized for Text keys.
TwoDArrayWritable	A Writable for 2D arrays containing a matrix of instances of a class.
UTF8	Deprecated. replaced by Text
UTF8.Comparator	A WritableComparator optimized for UTF8 keys.
VersionedWritable	A base class for Writables that provides version checking.
VIntWritable	A WritableComparable for integer values stored in variable-length format.
VLongWritable	A WritableComparable for longs in a variable-length format.
WritableComparator	A Comparator for WritableComparables.
WritableFactories	Factories for non-public writables.
WritableName	Utility to permit renaming of Writable implementation classes without invalidiating files that contain their class name.
WritableUtils

Enum Summary

SequenceFile.CompressionType

The type of compression.

Exception Summary

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().

Package org.apache.hadoop.io Description

Generic i/o code for use when reading and writing data to the network, to databases, and to files.