org.apache.hadoop.mapred.join

类 JoinRecordReader.JoinDelegationIterator

java.lang.Object

org.apache.hadoop.mapred.join.JoinRecordReader.JoinDelegationIterator

所有已实现的接口:

ResetableIterator<TupleWritable>

封闭类:

JoinRecordReader<K extends WritableComparable>

protected class JoinRecordReader.JoinDelegationIterator
extends Object
implements ResetableIterator<TupleWritable>

Since the JoinCollector is effecting our operation, we need only provide an iterator proxy wrapping its operation.

嵌套类概要

从接口继承的嵌套类/接口 org.apache.hadoop.mapred.join.ResetableIterator

ResetableIterator.EMPTY<U extends Writable>

构造器概要

构造器

限定符	构造器和说明
protected	JoinRecordReader.JoinDelegationIterator()

方法概要

方法

限定符和类型	方法和说明
void	add(TupleWritable item) Add an element to the collection of elements to iterate over.
void	clear() Close datasources, but do not release internal resources.
void	close() Close datasources and release resources.
boolean	hasNext() True if a call to next may return a value.
boolean	next(TupleWritable val) Assign next value to actual.
boolean	replay(TupleWritable val) Assign last value returned to actual.
void	reset() Set iterator to return to the start of its range.

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

JoinRecordReader.JoinDelegationIterator

protected JoinRecordReader.JoinDelegationIterator()

方法详细资料

hasNext

public boolean hasNext()

从接口复制的说明: ResetableIterator

True if a call to next may return a value. This is permitted false positives, but not false negatives.

指定者:

hasNext 在接口中 ResetableIterator<TupleWritable>

next

public boolean next(TupleWritable val)
             throws IOException

从接口复制的说明: ResetableIterator

Assign next value to actual. It is required that elements added to a ResetableIterator be returned in the same order after a call to ResetableIterator.reset() (FIFO). Note that a call to this may fail for nested joins (i.e. more elements available, but none satisfying the constraints of the join)

指定者:

next 在接口中 ResetableIterator<TupleWritable>

抛出:

IOException

replay

public boolean replay(TupleWritable val)
               throws IOException

从接口复制的说明: ResetableIterator

Assign last value returned to actual.

指定者:

replay 在接口中 ResetableIterator<TupleWritable>

抛出:

IOException

reset

public void reset()

从接口复制的说明: ResetableIterator

Set iterator to return to the start of its range. Must be called after calling ResetableIterator.add(T) to avoid a ConcurrentModificationException.

指定者:

reset 在接口中 ResetableIterator<TupleWritable>

add

public void add(TupleWritable item)
         throws IOException

从接口复制的说明: ResetableIterator

Add an element to the collection of elements to iterate over.

指定者:

add 在接口中 ResetableIterator<TupleWritable>

抛出:

IOException

close

public void close()
           throws IOException

从接口复制的说明: ResetableIterator

Close datasources and release resources. Calling methods on the iterator after calling close has undefined behavior.

指定者:

close 在接口中 ResetableIterator<TupleWritable>

抛出:

IOException

clear

public void clear()

从接口复制的说明: ResetableIterator

Close datasources, but do not release internal resources. Calling this method should permit the object to be reused with a different datasource.

指定者:

clear 在接口中 ResetableIterator<TupleWritable>