Uses of Interface
org.apache.hadoop.io.Writable

Packages that use Writable

Package	Description
org.apache.hadoop.conf	Configuration of system parameters.
org.apache.hadoop.fs	An abstract file system API.
org.apache.hadoop.fs.permission
org.apache.hadoop.io	Generic i/o code for use when reading and writing data to the network, to databases, and to files.
org.apache.hadoop.mapred
org.apache.hadoop.mapred.join
org.apache.hadoop.mapred.lib.aggregate
org.apache.hadoop.mapreduce
org.apache.hadoop.mapreduce.counters	This package contains the implementations of different types of map-reduce counters.
org.apache.hadoop.mapreduce.lib.aggregate
org.apache.hadoop.mapreduce.lib.input
org.apache.hadoop.mapreduce.lib.join
org.apache.hadoop.mapreduce.lib.output
org.apache.hadoop.record	(DEPRECATED) Hadoop record I/O contains classes and a record description language translator for simplifying serialization and deserialization of records in a language-neutral manner.
org.apache.hadoop.record.meta
org.apache.hadoop.security.authorize
org.apache.hadoop.security.token
org.apache.hadoop.security.token.delegation
org.apache.hadoop.util	Common utilities.
org.apache.hadoop.util.bloom
org.apache.hadoop.yarn.conf
org.apache.hadoop.yarn.logaggregation
org.apache.hadoop.yarn.security
org.apache.hadoop.yarn.security.client

Uses of Writable in org.apache.hadoop.conf

Classes in org.apache.hadoop.conf that implement Writable

Modifier and Type	Class and Description
class	Configuration Provides access to configuration parameters.

Uses of Writable in org.apache.hadoop.fs

Classes in org.apache.hadoop.fs that implement Writable

Modifier and Type	Class and Description
class	ContentSummary Store the summary of a content (a directory or a file).
class	FileChecksum An abstract class representing file checksums for files.
class	FileStatus Interface that represents the client side information for a file.
class	FsServerDefaults Provides server default configuration values to clients.
class	FsStatus This class is used to represent the capacity, free and used space on a FileSystem.
class	LocatedFileStatus This class defines a FileStatus that includes a file's block locations.

Uses of Writable in org.apache.hadoop.fs.permission

Classes in org.apache.hadoop.fs.permission that implement Writable

Modifier and Type	Class and Description
class	FsPermission A class for file/directory permissions.

Uses of Writable in org.apache.hadoop.io

Subinterfaces of Writable in org.apache.hadoop.io

Modifier and Type	Interface and Description
interface	WritableComparable<T> A Writable which is also Comparable.

Classes in org.apache.hadoop.io that implement Writable

Modifier and Type	Class and Description
class	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.
class	ArrayPrimitiveWritable This is a wrapper class.
class	ArrayWritable A Writable for arrays containing instances of a class.
class	BooleanWritable A WritableComparable for booleans.
class	BytesWritable A byte sequence that is usable as a key or value.
class	ByteWritable A WritableComparable for a single byte.
class	CompressedWritable A base-class for Writables which store themselves compressed and lazily inflate on field access.
class	DoubleWritable Writable for Double values.
class	EnumSetWritable<E extends Enum<E>> A Writable wrapper for EnumSet.
class	FloatWritable A WritableComparable for floats.
class	GenericWritable A wrapper for Writable instances.
class	IntWritable A WritableComparable for ints.
class	LongWritable A WritableComparable for longs.
class	MapWritable A Writable Map.
class	MD5Hash A Writable for MD5 hash values.
class	NullWritable Singleton Writable with no data.
class	ObjectWritable A polymorphic Writable that writes an instance with it's class name.
class	ShortWritable A WritableComparable for shorts.
class	SortedMapWritable A Writable SortedMap.
class	Text This class stores text using standard UTF8 encoding.
class	TwoDArrayWritable A Writable for 2D arrays containing a matrix of instances of a class.
class	VersionedWritable A base class for Writables that provides version checking.
class	VIntWritable A WritableComparable for integer values stored in variable-length format.
class	VLongWritable A WritableComparable for longs in a variable-length format.

Methods in org.apache.hadoop.io with type parameters of type Writable

Modifier and Type	Method and Description
static <T extends Writable> T	WritableUtils.clone(T orig, Configuration conf) Make a copy of a writable object using serialization to a buffer.

Methods in org.apache.hadoop.io that return Writable

Modifier and Type	Method and Description
Writable[]	ArrayWritable.get()
Writable	GenericWritable.get() Return the wrapped instance.
Writable[][]	TwoDArrayWritable.get()
Writable	SortedMapWritable.get(Object key)
Writable	MapWritable.get(Object key)
Writable	WritableFactory.newInstance() Return a new instance.
static Writable	WritableFactories.newInstance(Class<? extends Writable> c) Create a new instance of a class with a defined factory.
static Writable	WritableFactories.newInstance(Class<? extends Writable> c, Configuration conf) Create a new instance of a class with a defined factory.
Writable	SortedMapWritable.put(WritableComparable key, Writable value)
Writable	MapWritable.put(Writable key, Writable value)
Writable	SortedMapWritable.remove(Object key)
Writable	MapWritable.remove(Object key)

Methods in org.apache.hadoop.io that return types with arguments of type Writable

Modifier and Type	Method and Description
Set<Map.Entry<WritableComparable,Writable>>	SortedMapWritable.entrySet()
Set<Map.Entry<Writable,Writable>>	MapWritable.entrySet()
Set<Map.Entry<Writable,Writable>>	MapWritable.entrySet()
SortedMap<WritableComparable,Writable>	SortedMapWritable.headMap(WritableComparable toKey)
Set<Writable>	MapWritable.keySet()
SortedMap<WritableComparable,Writable>	SortedMapWritable.subMap(WritableComparable fromKey, WritableComparable toKey)
SortedMap<WritableComparable,Writable>	SortedMapWritable.tailMap(WritableComparable fromKey)
Collection<Writable>	SortedMapWritable.values()
Collection<Writable>	MapWritable.values()

Methods in org.apache.hadoop.io with parameters of type Writable

Modifier and Type	Method and Description
static void	WritableUtils.cloneInto(Writable dst, Writable src) Deprecated. use ReflectionUtils.cloneInto instead.
protected void	AbstractMapWritable.copy(Writable other) Used by child copy constructors.
Writable	SortedMapWritable.put(WritableComparable key, Writable value)
Writable	MapWritable.put(Writable key, Writable value)
void	GenericWritable.set(Writable obj) Set the instance that is wrapped.
void	ArrayWritable.set(Writable[] values)
void	TwoDArrayWritable.set(Writable[][] values)
static byte[]	WritableUtils.toByteArray(Writable... writables) Convert writables to a byte array

Method parameters in org.apache.hadoop.io with type arguments of type Writable

Modifier and Type	Method and Description
static long	MapFile.fix(FileSystem fs, Path dir, Class<? extends Writable> keyClass, Class<? extends Writable> valueClass, boolean dryrun, Configuration conf) This method attempts to fix a corrupt MapFile by re-creating its index.
static long	MapFile.fix(FileSystem fs, Path dir, Class<? extends Writable> keyClass, Class<? extends Writable> valueClass, boolean dryrun, Configuration conf) This method attempts to fix a corrupt MapFile by re-creating its index.
static Writable	WritableFactories.newInstance(Class<? extends Writable> c) Create a new instance of a class with a defined factory.
static Writable	WritableFactories.newInstance(Class<? extends Writable> c, Configuration conf) Create a new instance of a class with a defined factory.
void	MapWritable.putAll(Map<? extends Writable,? extends Writable> t)
void	MapWritable.putAll(Map<? extends Writable,? extends Writable> t)
void	SortedMapWritable.putAll(Map<? extends WritableComparable,? extends Writable> t)

Constructors in org.apache.hadoop.io with parameters of type Writable

Constructor and Description
ArrayWritable(Class<? extends Writable> valueClass, Writable[] values)
TwoDArrayWritable(Class valueClass, Writable[][] values)

Constructor parameters in org.apache.hadoop.io with type arguments of type Writable

Constructor and Description
ArrayWritable(Class<? extends Writable> valueClass)
ArrayWritable(Class<? extends Writable> valueClass, Writable[] values)

Uses of Writable in org.apache.hadoop.mapred

Subinterfaces of Writable in org.apache.hadoop.mapred

Modifier and Type	Interface and Description
interface	InputSplit InputSplit represents the data to be processed by an individual Mapper.
interface	InputSplitWithLocationInfo

Classes in org.apache.hadoop.mapred that implement Writable

Modifier and Type	Class and Description
class	ClusterStatus Status information on the current state of the Map-Reduce cluster.
class	Counters A set of named counters.
static class	Counters.Counter A counter record, comprising its name and value.
static class	Counters.Group Group of counters, comprising of counters from a particular counter Enum class.
class	FileSplit A section of an input file.
class	JobConf A map/reduce job configuration.
class	JobQueueInfo Class that contains the information regarding the Job Queues which are maintained by the Hadoop Map/Reduce framework.
class	MultiFileSplit A sub-collection of input files.

Methods in org.apache.hadoop.mapred with type parameters of type Writable

Modifier and Type	Method and Description
static <K extends WritableComparable,V extends Writable> Writable	MapFileOutputFormat.getEntry(org.apache.hadoop.io.MapFile.Reader[] readers, Partitioner<K,V> partitioner, K key, V value) Get an entry from output generated by this class.

Methods in org.apache.hadoop.mapred that return Writable

Modifier and Type	Method and Description
static <K extends WritableComparable,V extends Writable> Writable	MapFileOutputFormat.getEntry(org.apache.hadoop.io.MapFile.Reader[] readers, Partitioner<K,V> partitioner, K key, V value) Get an entry from output generated by this class.

Methods in org.apache.hadoop.mapred that return types with arguments of type Writable

Modifier and Type	Method and Description
RecordWriter<WritableComparable,Writable>	MapFileOutputFormat.getRecordWriter(FileSystem ignored, JobConf job, String name, Progressable progress)
static Class<? extends Writable>	SequenceFileAsBinaryOutputFormat.getSequenceFileOutputValueClass(JobConf conf) Get the value class for the SequenceFile

Uses of Writable in org.apache.hadoop.mapred.join

Classes in org.apache.hadoop.mapred.join with type parameters of type Writable

Modifier and Type	Class and Description
class	ArrayListBackedIterator<X extends Writable> This class provides an implementation of ResetableIterator.
interface	ComposableInputFormat<K extends WritableComparable,V extends Writable> Refinement of InputFormat requiring implementors to provide ComposableRecordReader instead of RecordReader.
interface	ComposableRecordReader<K extends WritableComparable,V extends Writable> Additional operations required of a RecordReader to participate in a join.
class	CompositeRecordReader<K extends WritableComparable,V extends Writable,X extends Writable> A RecordReader that can effect joins of RecordReaders sharing a common key type and partitioning.
class	CompositeRecordReader<K extends WritableComparable,V extends Writable,X extends Writable> A RecordReader that can effect joins of RecordReaders sharing a common key type and partitioning.
class	MultiFilterRecordReader<K extends WritableComparable,V extends Writable> Base class for Composite join returning values derived from multiple sources, but generally not tuples.
class	OverrideRecordReader<K extends WritableComparable,V extends Writable> Prefer the "rightmost" data source for this key.
interface	ResetableIterator<T extends Writable> This defines an interface to a stateful Iterator that can replay elements added to it directly.
class	StreamBackedIterator<X extends Writable> This class provides an implementation of ResetableIterator.
class	WrappedRecordReader<K extends WritableComparable,U extends Writable> Proxy class for a RecordReader participating in the join framework.

Classes in org.apache.hadoop.mapred.join that implement Writable

Modifier and Type	Class and Description
class	CompositeInputSplit This InputSplit contains a set of child InputSplits.

Constructors in org.apache.hadoop.mapred.join with parameters of type Writable

Constructor and Description
TupleWritable(Writable[] vals) Initialize tuple with storage; unknown whether any of them contain "written" values.

Uses of Writable in org.apache.hadoop.mapred.lib.aggregate

Classes in org.apache.hadoop.mapred.lib.aggregate with type parameters of type Writable

Modifier and Type	Class and Description
class	ValueAggregatorCombiner<K1 extends WritableComparable,V1 extends Writable> This class implements the generic combiner of Aggregate.
class	ValueAggregatorJobBase<K1 extends WritableComparable,V1 extends Writable> This abstract class implements some common functionalities of the the generic mapper, reducer and combiner classes of Aggregate.
class	ValueAggregatorMapper<K1 extends WritableComparable,V1 extends Writable> This class implements the generic mapper of Aggregate.
class	ValueAggregatorReducer<K1 extends WritableComparable,V1 extends Writable> This class implements the generic reducer of Aggregate.

Uses of Writable in org.apache.hadoop.mapreduce

Subinterfaces of Writable in org.apache.hadoop.mapreduce

Modifier and Type	Interface and Description
interface	Counter A named counter that tracks the progress of a map/reduce job.
interface	CounterGroup A group of Counters that logically belong together.

Classes in org.apache.hadoop.mapreduce that implement Writable

Modifier and Type	Class and Description
class	ClusterMetrics Status information on the current state of the Map-Reduce cluster.
class	ID A general identifier, which internally stores the id as an integer.
class	JobID JobID represents the immutable and unique identifier for the job.
class	JobStatus Describes the current status of a job.
class	QueueAclsInfo Class to encapsulate Queue ACLs for a particular user.
class	QueueInfo Class that contains the information regarding the Job Queues which are maintained by the Hadoop Map/Reduce framework.
class	TaskAttemptID TaskAttemptID represents the immutable and unique identifier for a task attempt.
class	TaskCompletionEvent This is used to track task completion events on job tracker.
class	TaskID TaskID represents the immutable and unique identifier for a Map or Reduce Task.
class	org.apache.hadoop.mapreduce.TaskReport A report on the state of a task.
class	TaskTrackerInfo Information about TaskTracker.

Uses of Writable in org.apache.hadoop.mapreduce.counters

Subinterfaces of Writable in org.apache.hadoop.mapreduce.counters

Modifier and Type	Interface and Description
interface	CounterGroupBase<T extends Counter> The common counter group interface.

Classes in org.apache.hadoop.mapreduce.counters that implement Writable

Modifier and Type	Class and Description
class	AbstractCounters<C extends Counter,G extends CounterGroupBase<C>> An abstract class to provide common implementation for the Counters container in both mapred and mapreduce packages.

Uses of Writable in org.apache.hadoop.mapreduce.lib.aggregate

Classes in org.apache.hadoop.mapreduce.lib.aggregate with type parameters of type Writable

Modifier and Type	Class and Description
class	ValueAggregatorCombiner<K1 extends WritableComparable<?>,V1 extends Writable> This class implements the generic combiner of Aggregate.
class	ValueAggregatorJobBase<K1 extends WritableComparable<?>,V1 extends Writable> This abstract class implements some common functionalities of the the generic mapper, reducer and combiner classes of Aggregate.
class	ValueAggregatorMapper<K1 extends WritableComparable<?>,V1 extends Writable> This class implements the generic mapper of Aggregate.
class	ValueAggregatorReducer<K1 extends WritableComparable<?>,V1 extends Writable> This class implements the generic reducer of Aggregate.

Uses of Writable in org.apache.hadoop.mapreduce.lib.input

Classes in org.apache.hadoop.mapreduce.lib.input that implement Writable

Modifier and Type	Class and Description
class	CombineFileSplit A sub-collection of input files.

Uses of Writable in org.apache.hadoop.mapreduce.lib.join

Classes in org.apache.hadoop.mapreduce.lib.join with type parameters of type Writable

Modifier and Type	Class and Description
class	ArrayListBackedIterator<X extends Writable> This class provides an implementation of ResetableIterator.
class	ComposableInputFormat<K extends WritableComparable<?>,V extends Writable> Refinement of InputFormat requiring implementors to provide ComposableRecordReader instead of RecordReader.
class	ComposableRecordReader<K extends WritableComparable<?>,V extends Writable> Additional operations required of a RecordReader to participate in a join.
class	CompositeRecordReader<K extends WritableComparable<?>,V extends Writable,X extends Writable> A RecordReader that can effect joins of RecordReaders sharing a common key type and partitioning.
class	CompositeRecordReader<K extends WritableComparable<?>,V extends Writable,X extends Writable> A RecordReader that can effect joins of RecordReaders sharing a common key type and partitioning.
class	MultiFilterRecordReader<K extends WritableComparable<?>,V extends Writable> Base class for Composite join returning values derived from multiple sources, but generally not tuples.
class	OverrideRecordReader<K extends WritableComparable<?>,V extends Writable> Prefer the "rightmost" data source for this key.
interface	ResetableIterator<T extends Writable> This defines an interface to a stateful Iterator that can replay elements added to it directly.
class	StreamBackedIterator<X extends Writable> This class provides an implementation of ResetableIterator.
class	WrappedRecordReader<K extends WritableComparable<?>,U extends Writable> Proxy class for a RecordReader participating in the join framework.

Classes in org.apache.hadoop.mapreduce.lib.join that implement Writable

Modifier and Type	Class and Description
class	TupleWritable Writable type storing multiple Writables.

Fields in org.apache.hadoop.mapreduce.lib.join declared as Writable

Modifier and Type	Field and Description
protected X	CompositeRecordReader.value

Methods in org.apache.hadoop.mapreduce.lib.join that return Writable

Modifier and Type	Method and Description
Writable	TupleWritable.get(int i) Get ith Writable from Tuple.

Methods in org.apache.hadoop.mapreduce.lib.join that return types with arguments of type Writable

Modifier and Type	Method and Description
Iterator<Writable>	TupleWritable.iterator() Return an iterator over the elements in this tuple.

Constructors in org.apache.hadoop.mapreduce.lib.join with parameters of type Writable

Constructor and Description
TupleWritable(Writable[] vals) Initialize tuple with storage; unknown whether any of them contain "written" values.

Uses of Writable in org.apache.hadoop.mapreduce.lib.output

Methods in org.apache.hadoop.mapreduce.lib.output with type parameters of type Writable

Modifier and Type	Method and Description
static <K extends WritableComparable<?>,V extends Writable> Writable	MapFileOutputFormat.getEntry(org.apache.hadoop.io.MapFile.Reader[] readers, Partitioner<K,V> partitioner, K key, V value) Get an entry from output generated by this class.

Methods in org.apache.hadoop.mapreduce.lib.output that return Writable

Modifier and Type	Method and Description
static <K extends WritableComparable<?>,V extends Writable> Writable	MapFileOutputFormat.getEntry(org.apache.hadoop.io.MapFile.Reader[] readers, Partitioner<K,V> partitioner, K key, V value) Get an entry from output generated by this class.

Methods in org.apache.hadoop.mapreduce.lib.output that return types with arguments of type Writable

Modifier and Type	Method and Description
RecordWriter<WritableComparable<?>,Writable>	MapFileOutputFormat.getRecordWriter(TaskAttemptContext context)
static Class<? extends Writable>	SequenceFileAsBinaryOutputFormat.getSequenceFileOutputValueClass(JobContext job) Get the value class for the SequenceFile

Uses of Writable in org.apache.hadoop.record

Classes in org.apache.hadoop.record that implement Writable

Modifier and Type	Class and Description
class	Record Deprecated. Replaced by Avro.

Uses of Writable in org.apache.hadoop.record.meta

Classes in org.apache.hadoop.record.meta that implement Writable

Modifier and Type	Class and Description
class	RecordTypeInfo Deprecated. Replaced by Avro.

Uses of Writable in org.apache.hadoop.security.authorize

Classes in org.apache.hadoop.security.authorize that implement Writable

Modifier and Type	Class and Description
class	AccessControlList Class representing a configured access control list.

Uses of Writable in org.apache.hadoop.security.token

Classes in org.apache.hadoop.security.token that implement Writable

Modifier and Type	Class and Description
class	org.apache.hadoop.security.token.TokenIdentifier An identifier that identifies a token, may contain public information about a token, including its kind (or type).

Uses of Writable in org.apache.hadoop.security.token.delegation

Classes in org.apache.hadoop.security.token.delegation that implement Writable

Modifier and Type	Class and Description
class	org.apache.hadoop.security.token.delegation.AbstractDelegationTokenIdentifier

Uses of Writable in org.apache.hadoop.util

Methods in org.apache.hadoop.util with parameters of type Writable

Modifier and Type	Method and Description
static void	ReflectionUtils.cloneWritableInto(Writable dst, Writable src) Deprecated.

Uses of Writable in org.apache.hadoop.util.bloom

Classes in org.apache.hadoop.util.bloom that implement Writable

Modifier and Type	Class and Description
class	BloomFilter Implements a Bloom filter, as defined by Bloom in 1970.
class	CountingBloomFilter Implements a counting Bloom filter, as defined by Fan et al.
class	DynamicBloomFilter Implements a dynamic Bloom filter, as defined in the INFOCOM 2006 paper.
class	org.apache.hadoop.util.bloom.Filter Defines the general behavior of a filter.
class	RetouchedBloomFilter Implements a retouched Bloom filter, as defined in the CoNEXT 2006 paper.

Uses of Writable in org.apache.hadoop.yarn.conf

Classes in org.apache.hadoop.yarn.conf that implement Writable

Modifier and Type	Class and Description
class	YarnConfiguration

Uses of Writable in org.apache.hadoop.yarn.logaggregation

Classes in org.apache.hadoop.yarn.logaggregation that implement Writable

Modifier and Type	Class and Description
static class	AggregatedLogFormat.LogKey

Uses of Writable in org.apache.hadoop.yarn.security

Classes in org.apache.hadoop.yarn.security that implement Writable

Modifier and Type	Class and Description
class	AMRMTokenIdentifier AMRMTokenIdentifier is the TokenIdentifier to be used by ApplicationMasters to authenticate to the ResourceManager.
class	ContainerTokenIdentifier TokenIdentifier for a container.
class	NMTokenIdentifier

Uses of Writable in org.apache.hadoop.yarn.security.client

Classes in org.apache.hadoop.yarn.security.client that implement Writable

Modifier and Type	Class and Description
class	ClientToAMTokenIdentifier
class	RMDelegationTokenIdentifier Delegation Token Identifier that identifies the delegation tokens from the Resource Manager.
class	TimelineDelegationTokenIdentifier
class	org.apache.hadoop.yarn.security.client.YARNDelegationTokenIdentifier