TupleWritable (Hadoop 1.2.2-SNAPSHOT API)

java.lang.Object
- org.apache.hadoop.mapred.join.TupleWritable

所有已实现的接口:

Iterable<Writable>, Writable
```
public class TupleWritable
extends Object
implements Writable, Iterable<Writable>
```
Writable type storing multiple Writables. This is *not* a general-purpose tuple type. In almost all cases, users are encouraged to implement their own serializable types, which can perform better validation and provide more efficient encodings than this class is capable. TupleWritable relies on the join framework for type safety and assumes its instances will rarely be persisted, assumptions not only incompatible with, but contrary to the general case.

另请参阅:
Writable

构造器概要

构造器
构造器和说明
`TupleWritable()` Create an empty tuple with no allocated storage for writables.
`TupleWritable(Writable[] vals)` Initialize tuple with storage; unknown whether any of them contain "written" values.

方法概要

方法
限定符和类型	方法和说明
`boolean`	`equals(Object other)`
`Writable`	`get(int i)` Get ith Writable from Tuple.
`boolean`	`has(int i)` Return true if tuple has an element at the position provided.
`int`	`hashCode()`
`Iterator<Writable>`	`iterator()` Return an iterator over the elements in this tuple.
`void`	`readFields(DataInput in)` Deserialize the fields of this object from `in`.
`int`	`size()` The number of children in this Tuple.
`String`	`toString()` Convert Tuple to String as in the following.
`void`	`write(DataOutput out)` Writes each Writable to `out`.

从类继承的方法 java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 构造器详细资料
  - TupleWritable
```
public TupleWritable()
```
    Create an empty tuple with no allocated storage for writables.
  - TupleWritable
```
public TupleWritable(Writable[] vals)
```
    Initialize tuple with storage; unknown whether any of them contain "written" values.
- 方法详细资料
  - has
```
public boolean has(int i)
```
    Return true if tuple has an element at the position provided.
  - get
```
public Writable get(int i)
```
    Get ith Writable from Tuple.
  - size
```
public int size()
```
    The number of children in this Tuple.
  - equals
```
public boolean equals(Object other)
```
    覆盖:
    
    equals 在类中 Object
  - hashCode
```
public int hashCode()
```
    覆盖:
    
    hashCode 在类中 Object
  - iterator
```
public Iterator<Writable> iterator()
```
    Return an iterator over the elements in this tuple. Note that this doesn't flatten the tuple; one may receive tuples from this iterator.
    
    指定者:
    
    iterator 在接口中 Iterable<Writable>
  - toString
```
public String toString()
```
    Convert Tuple to String as in the following. [,,...,]
    
    覆盖:
    
    toString 在类中 Object
  - write
```
public void write(DataOutput out)
           throws IOException
```
    Writes each Writable to out. TupleWritable format: <count><type1><type2>...<typen><obj1><obj2>...<objn>
    
    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

类 TupleWritable

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

TupleWritable

TupleWritable

方法详细资料

has

get

size

equals

hashCode

iterator

toString

write

readFields