org.apache.hadoop.io

类 AbstractMapWritable

java.lang.Object

org.apache.hadoop.io.AbstractMapWritable

所有已实现的接口:

Configurable, Writable

直接已知子类:

MapWritable, SortedMapWritable

public abstract class AbstractMapWritable
extends Object
implements Writable, Configurable

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 ids range from 1 to 127 so there can be at most 127 distinct classes in any specific map instance.

构造器概要

构造器

限定符	构造器和说明
protected	AbstractMapWritable() constructor.

方法概要

方法

限定符和类型	方法和说明
protected void	addToMap(Class clazz) Add a Class to the maps if it is not already present.
protected void	copy(Writable other) Used by child copy constructors.
protected Class	getClass(byte id)
Configuration	getConf() Return the configuration used by this object.
protected byte	getId(Class clazz)
void	readFields(DataInput in) Deserialize the fields of this object from in.
void	setConf(Configuration conf) Set the configuration to be used by this object.
void	write(DataOutput out) Serialize the fields of this object to out.

从类继承的方法 java.lang.Object

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

构造器详细资料

AbstractMapWritable

protected AbstractMapWritable()

constructor.

方法详细资料

addToMap

protected void addToMap(Class clazz)

Add a Class to the maps if it is not already present.

getClass

protected Class getClass(byte id)

返回:

the Class class for the specified id

getId

protected byte getId(Class clazz)

返回:

the id for the specified Class

copy

protected void copy(Writable other)

Used by child copy constructors.

getConf

public Configuration getConf()

从接口复制的说明: Configurable

Return the configuration used by this object.

指定者:

getConf 在接口中 Configurable

返回:

the conf

setConf

public void setConf(Configuration conf)

从接口复制的说明: Configurable

Set the configuration to be used by this object.

指定者:

setConf 在接口中 Configurable

参数:

conf - the conf to set

write

public void write(DataOutput out)
           throws IOException

Serialize the fields of this object to out.

指定者:

write 在接口中 Writable

参数:

out - DataOuput to serialize this object into.

抛出:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Deserialize the fields of this object from in.

For efficiency, implementations should attempt to re-use storage in the existing object where possible.

指定者:

readFields 在接口中 Writable

参数:

in - DataInput to deseriablize this object from.

抛出:

IOException