org.apache.cassandra.utils.btree

Interface UpdateFunction<K,V>

All Known Implementing Classes:

ColumnData.Reconciler, UpdateFunction.Simple

public interface UpdateFunction<K,V>

An interface defining the method to be applied to the existing and replacing object in a BTree. The objects returned by the methods will be the object that need to be stored in the BTree.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	UpdateFunction.Simple<V>

Field Summary

Fields

Modifier and Type	Field and Description
static UpdateFunction.Simple<java.lang.Object>	noOp

Method Summary

Modifier and Type	Method and Description
V	insert(K insert) Computes the value that should be inserted in the BTree.
V	merge(V replacing, K update) Computes the result of merging the existing value with the one from the update.
static <K> UpdateFunction<K,K>	noOp()
void	onAllocatedOnHeap(long heapSize)

Field Detail

noOp

static final UpdateFunction.Simple<java.lang.Object> noOp

Method Detail

insert

V insert(K insert)

Computes the value that should be inserted in the BTree.

Parameters:

insert - the update value

Returns:

the value that should be inserted in the BTree

merge

V merge(V replacing,
        K update)

Computes the result of merging the existing value with the one from the update.

Parameters:

replacing - the value in the original tree we have matched

update - the value in the updating collection that matched

Returns:

the value to insert into the new tree

onAllocatedOnHeap

void onAllocatedOnHeap(long heapSize)

Parameters:

heapSize - extra heap space allocated (over previous tree)

noOp

static <K> UpdateFunction<K,K> noOp()