java.lang.Object
- org.apache.flink.table.runtime.operators.rank.TopNBuffer

All Implemented Interfaces:

Serializable
```
public class TopNBuffer
extends Object
implements Serializable
```
TopNBuffer stores mapping from sort key to records list, sortKey is RowData type, each record is RowData type. TopNBuffer could also track rank number of each record.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

TopNBuffer(Comparator<RowData> sortKeyComparator, Supplier<Collection<RowData>> valueSupplier)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`checkSortKeyInBufferRange(RowData sortKey, long topNum)`	Checks whether the record should be put into the buffer.
`boolean`	`containsKey(RowData key)`	Returns `true` if the buffer contains a mapping for the specified key.
`Set<Map.Entry<RowData,Collection<RowData>>>`	`entrySet()`	Returns a `Set` view of the mappings contained in the buffer.
`Collection<RowData>`	`get(RowData sortKey)`	Gets the record list from the buffer under the sortKey.
`int`	`getCurrentTopNum()`	Gets number of total records.
`RowData`	`getElement(int rank)`	Gets record which rank is given value.
`Comparator<RowData>`	`getSortKeyComparator()`	Gets sort key comparator used by buffer.
`RowData`	`lastElement()`	Returns the last record of the last Entry in the buffer.
`Map.Entry<RowData,Collection<RowData>>`	`lastEntry()`	Returns the last Entry in the buffer.
`int`	`put(RowData sortKey, RowData value)`	Appends a record into the buffer.
`void`	`putAll(RowData sortKey, Collection<RowData> values)`	Puts a record list into the buffer under the sortKey.
`void`	`remove(RowData sortKey, RowData value)`
`void`	`removeAll(RowData sortKey)`	Removes all record list from the buffer under the sortKey.
`RowData`	`removeLast()`	Removes the last record of the last Entry in the buffer.

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

- Constructor Detail
  - TopNBuffer
```
public TopNBuffer(Comparator<RowData> sortKeyComparator,
                  Supplier<Collection<RowData>> valueSupplier)
```
- Method Detail
  - put
```
public int put(RowData sortKey,
               RowData value)
```
    Appends a record into the buffer.
    
    Parameters:
    
    sortKey - sort key with which the specified value is to be associated
    
    value - record which is to be appended
    
    Returns:
    
    the size of the collection under the sortKey.
  - putAll
```
public void putAll(RowData sortKey,
                   Collection<RowData> values)
```
    Puts a record list into the buffer under the sortKey. Note: if buffer already contains sortKey, putAll will overwrite the previous value
    
    Parameters:
    
    sortKey - sort key with which the specified values are to be associated
    
    values - record lists to be associated with the specified key
  - get
```
public Collection<RowData> get(RowData sortKey)
```
    Gets the record list from the buffer under the sortKey.
    
    Parameters:
    
    sortKey - key to get
    
    Returns:
    
    the record list from the buffer under the sortKey
  - remove
```
public void remove(RowData sortKey,
                   RowData value)
```
  - removeAll
```
public void removeAll(RowData sortKey)
```
    Removes all record list from the buffer under the sortKey.
    
    Parameters:
    
    sortKey - key to remove
  - removeLast
```
public RowData removeLast()
```
    Removes the last record of the last Entry in the buffer.
    
    Returns:
    
    removed record
  - lastElement
```
public RowData lastElement()
```
    Returns the last record of the last Entry in the buffer.
  - getElement
```
public RowData getElement(int rank)
```
    Gets record which rank is given value.
    
    Parameters:
    
    rank - rank value to search
    
    Returns:
    
    the record which rank is given value
  - entrySet
```
public Set<Map.Entry<RowData,Collection<RowData>>> entrySet()
```
    Returns a Set view of the mappings contained in the buffer.
  - lastEntry
```
public Map.Entry<RowData,Collection<RowData>> lastEntry()
```
    Returns the last Entry in the buffer. Returns null if the TreeMap is empty.
  - containsKey
```
public boolean containsKey(RowData key)
```
    Returns true if the buffer contains a mapping for the specified key.
    
    Parameters:
    
    key - key whose presence in the buffer is to be tested
    
    Returns:
    
    true if the buffer contains a mapping for the specified key
  - getCurrentTopNum
```
public int getCurrentTopNum()
```
    Gets number of total records.
    
    Returns:
    
    the number of total records.
  - getSortKeyComparator
```
public Comparator<RowData> getSortKeyComparator()
```
    Gets sort key comparator used by buffer.
    
    Returns:
    
    sort key comparator used by buffer
  - checkSortKeyInBufferRange
```
public boolean checkSortKeyInBufferRange(RowData sortKey,
                                         long topNum)
```
    Checks whether the record should be put into the buffer.
    
    Parameters:
    
    sortKey - sortKey to test
    
    topNum - buffer to add
    
    Returns:
    
    true if the record should be put into the buffer.

Class TopNBuffer

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

TopNBuffer

Method Detail

put

putAll

get

remove

removeAll

removeLast

lastElement

getElement

entrySet

lastEntry

containsKey

getCurrentTopNum

getSortKeyComparator

checkSortKeyInBufferRange