ColumnReader (Apache Parquet Column 1.14.2 API)

All Known Implementing Classes:

ColumnReaderImpl
```
public interface ColumnReader
```
Reader for (repetition level, definition level, values) triplets. At any given point in time, a ColumnReader points to a single (r, d, v) triplet. In order to move to the next triplet, call consume().
Depending on the type and the encoding of the column only a subset of the get* methods are implemented. Dictionary specific methods enable the upper layers to read the dictionary IDs without decoding the data. In particular the Converter will decode the strings in the dictionary only once and iterate on the dictionary IDs instead of the values.
Each iteration looks at the current definition level and value as well as the next repetition level:
- The current definition level defines if the value is null.
- If the value is defined we can read it with the correct get*() method.
- Looking ahead to the next repetition determines what is the next column to read for in the FSA.

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`consume()` Consume the current triplet, moving to the next value.
`Binary`	`getBinary()`
`boolean`	`getBoolean()`
`int`	`getCurrentDefinitionLevel()`
`int`	`getCurrentRepetitionLevel()` must return 0 when isFullyConsumed() == true
`int`	`getCurrentValueDictionaryID()` available when the underlying encoding is dictionary based
`ColumnDescriptor`	`getDescriptor()`
`double`	`getDouble()`
`float`	`getFloat()`
`int`	`getInteger()`
`long`	`getLong()`
`long`	`getTotalValueCount()` Deprecated. will be removed in 2.0.0; Total values might not be able to be counted before reading the values (e.g. in case of column index based filtering)
`void`	`skip()` Skip the current value
`void`	`writeCurrentValueToConverter()` writes the current value to the converter

- Method Detail
  - getTotalValueCount
```
@Deprecated
long getTotalValueCount()
```
    Deprecated. will be removed in 2.0.0; Total values might not be able to be counted before reading the values (e.g. in case of column index based filtering)
    
    Returns:
    
    the totalCount of values to be consumed
  - consume
```
void consume()
```
    Consume the current triplet, moving to the next value.
  - getCurrentRepetitionLevel
```
int getCurrentRepetitionLevel()
```
    must return 0 when isFullyConsumed() == true
    
    Returns:
    
    the repetition level for the current value
  - getCurrentDefinitionLevel
```
int getCurrentDefinitionLevel()
```
    Returns:
    
    the definition level for the current value
  - writeCurrentValueToConverter
```
void writeCurrentValueToConverter()
```
    writes the current value to the converter
  - skip
```
void skip()
```
    Skip the current value
  - getCurrentValueDictionaryID
```
int getCurrentValueDictionaryID()
```
    available when the underlying encoding is dictionary based
    
    Returns:
    
    the dictionary id for the current value
  - getInteger
```
int getInteger()
```
    Returns:
    
    the current value
  - getBoolean
```
boolean getBoolean()
```
    Returns:
    
    the current value
  - getLong
```
long getLong()
```
    Returns:
    
    the current value
  - getBinary
```
Binary getBinary()
```
    Returns:
    
    the current value
  - getFloat
```
float getFloat()
```
    Returns:
    
    the current value
  - getDouble
```
double getDouble()
```
    Returns:
    
    the current value
  - getDescriptor
```
ColumnDescriptor getDescriptor()
```
    Returns:
    
    Descriptor of the column.

Interface ColumnReader

Method Summary

Method Detail

getTotalValueCount

consume

getCurrentRepetitionLevel

getCurrentDefinitionLevel

writeCurrentValueToConverter

skip

getCurrentValueDictionaryID

getInteger

getBoolean

getLong

getBinary

getFloat

getDouble

getDescriptor