DescReadBatchData (TsFile 1.2.1 API)

java.lang.Object
- org.apache.iotdb.tsfile.read.common.BatchData
- - org.apache.iotdb.tsfile.read.common.DescReadBatchData

Direct Known Subclasses:

DescReadWriteBatchData
```
public class DescReadBatchData
extends BatchData
```
This class is just for reading batch data reversely. The data source is from page reader. For example, the timeRet from pageReader is [1, 1000], It will be written in ascending sequence, but the sequence of reading will be 1000 -> 1.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.iotdb.tsfile.read.common.BatchData
  BatchData.BatchDataType

Field Summary
- Fields inherited from class org.apache.iotdb.tsfile.read.common.BatchData
  batchDataType, binaryRet, booleanRet, capacity, CAPACITY_THRESHOLD, count, dataType, doubleRet, floatRet, intRet, longRet, readCurArrayIndex, readCurListIndex, timeRet, vectorRet, writeCurArrayIndex, writeCurListIndex

Constructor Summary

Constructors
Constructor Description

DescReadBatchData()

DescReadBatchData(TSDataType dataType)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`BatchData`	`flip()`	When put data, the writeIndex increases while the readIndex remains 0.
`java.lang.Object`	`getValueInTimestamp(long time)`
`boolean`	`hasCurrent()`
`void`	`next()`
`void`	`resetBatchData()`	This method is used to reset batch data when more than one group by aggregation functions visit the same batch data

Methods inherited from class org.apache.iotdb.tsfile.read.common.BatchData
currentTime, currentTsPrimitiveType, currentValue, getBatchDataIterator, getBatchDataIterator, getBatchDataType, getBinary, getBinaryByIndex, getBoolean, getBooleanByIndex, getDataType, getDouble, getDoubleByIndex, getFloat, getFloatByIndex, getInt, getIntByIndex, getLastPairBeforeOrEqualTimestamp, getLong, getLongByIndex, getMaxTimestamp, getMinTimestamp, getReadCurArrayIndex, getReadCurListIndex, getTimeByIndex, getVector, getVectorByIndex, init, isEmpty, length, putAnObject, putBinary, putBoolean, putDouble, putFloat, putInt, putLong, putVector, resetBatchData, serializeData, setBinary, setBoolean, setDataType, setDouble, setFloat, setInt, setLong, setTime, setVector

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DescReadBatchData
```
public DescReadBatchData()
```
  - DescReadBatchData
```
public DescReadBatchData(TSDataType dataType)
```
- Method Detail
  - hasCurrent
```
public boolean hasCurrent()
```
    Overrides:
    
    hasCurrent in class BatchData
  - next
```
public void next()
```
    Overrides:
    
    next in class BatchData
  - resetBatchData
```
public void resetBatchData()
```
    Description copied from class: BatchData
    
    This method is used to reset batch data when more than one group by aggregation functions visit the same batch data
    
    Overrides:
    
    resetBatchData in class BatchData
  - flip
```
public BatchData flip()
```
    When put data, the writeIndex increases while the readIndex remains 0. For descending read, we need to read from writeIndex to 0 (set the readIndex to writeIndex)
    
    Overrides:
    
    flip in class BatchData
  - getValueInTimestamp
```
public java.lang.Object getValueInTimestamp(long time)
```
    Overrides:
    
    getValueInTimestamp in class BatchData