com.github.basking2.sdsai.dsds.node.tx

Class TransactionalNodeStore<USERKEY,STOREKEY,VALUE>

java.lang.Object

com.github.basking2.sdsai.dsds.node.tx.TransactionalNodeStore<USERKEY,STOREKEY,VALUE>

Type Parameters:

USERKEY - The user key type.

STOREKEY - The data store key type.

VALUE - The value being stored.

All Implemented Interfaces:

NodeStore<USERKEY,STOREKEY,VALUE>

public class TransactionalNodeStore<USERKEY,STOREKEY,VALUE>
extends java.lang.Object
implements NodeStore<USERKEY,STOREKEY,VALUE>

This represents a transaction against a NodeStore. Operations are stored cached internally until commit() is called or rollback() causes the data to be abandoned. A transaction. This is implemented as a NodeStore in which methods not related to the transaction are directly proxied to the NodeStore used to initialize this object.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	TransactionalNodeStore.SubTx<USERKEY,STOREKEY,VALUE> An interface to provide a callback for doing operations on sub-TransactionalNodeStores.

Constructor Summary

Constructors

Constructor and Description
TransactionalNodeStore(NodeStore<USERKEY,STOREKEY,VALUE> nodeStore)
TransactionalNodeStore(NodeStore<USERKEY,STOREKEY,VALUE> nodeStore, TransactionalNodeStore<USERKEY,STOREKEY,VALUE> parentTransaction) Create a new transaction that operates against the given NodeStore.

Method Summary

Modifier and Type	Method and Description
void	commit() Execute all operations in this transaction.
STOREKEY	convert(USERKEY key) Convert user keys to store keys.
STOREKEY	generateKey(Node<USERKEY,STOREKEY> node, VALUE value) Generate a key to store a node or data element.
VALUE	loadData(STOREKEY key) Load the user's data.
Node<USERKEY,STOREKEY>	loadNode(STOREKEY key) Load a node object from NodeStore.
void	removeData(STOREKEY key) Remove the given data key.
void	removeNode(STOREKEY key) Remove the given node key.
void	rollback() Rollback and clear all internal structures of this transaction.
void	store(STOREKEY key, Node<USERKEY,STOREKEY> node) Store the given node.
void	store(STOREKEY key, VALUE value) Store user data.
void	subTransaction(TransactionalNodeStore.SubTx<USERKEY,STOREKEY,VALUE> subTx) Give the user a sub-transaction which is merged into this transaction when TransactionalNodeStore.SubTx.buildTx(TransactionalNodeStore) returns.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransactionalNodeStore

public TransactionalNodeStore(NodeStore<USERKEY,STOREKEY,VALUE> nodeStore)

TransactionalNodeStore

public TransactionalNodeStore(NodeStore<USERKEY,STOREKEY,VALUE> nodeStore,
                              TransactionalNodeStore<USERKEY,STOREKEY,VALUE> parentTransaction)

Create a new transaction that operates against the given NodeStore.

Method Detail

subTransaction

public void subTransaction(TransactionalNodeStore.SubTx<USERKEY,STOREKEY,VALUE> subTx)

Give the user a sub-transaction which is merged into this transaction when TransactionalNodeStore.SubTx.buildTx(TransactionalNodeStore) returns.

rollback

public void rollback()

Rollback and clear all internal structures of this transaction.

commit

public void commit()

Execute all operations in this transaction.

convert

public STOREKEY convert(USERKEY key)

Convert user keys to store keys. This method, given a user's key, must always produce the same store key.

Specified by:

convert in interface NodeStore<USERKEY,STOREKEY,VALUE>

generateKey

public STOREKEY generateKey(Node<USERKEY,STOREKEY> node,
                            VALUE value)

Generate a key to store a node or data element. This key must be unique.

Specified by:

generateKey in interface NodeStore<USERKEY,STOREKEY,VALUE>

Parameters:

node - This is provided to implementations for some context. If generateKey is being called for the purposes of storing a user key, this will be null.

value - If a key is being generated for a user key value, it will be passed along. This is most useful when things like a PagedList are adding a value, but the List API does not provide a way to specify a key.

loadData

public VALUE loadData(STOREKEY key)

Load the user's data.

Specified by:

loadData in interface NodeStore<USERKEY,STOREKEY,VALUE>

Returns:

the user's data or null if it is not found.

loadNode

public Node<USERKEY,STOREKEY> loadNode(STOREKEY key)

Load a node object from NodeStore.

Specified by:

loadNode in interface NodeStore<USERKEY,STOREKEY,VALUE>

removeNode

public void removeNode(STOREKEY key)

Remove the given node key. If the key does not exist, this should return without error.

Specified by:

removeNode in interface NodeStore<USERKEY,STOREKEY,VALUE>

removeData

public void removeData(STOREKEY key)

Remove the given data key. If the key does not exist, this should return without error.

Specified by:

removeData in interface NodeStore<USERKEY,STOREKEY,VALUE>

store

public void store(STOREKEY key,
                  Node<USERKEY,STOREKEY> node)

Store the given node. If an object already exists at the key, it should be replaced.

Specified by:

store in interface NodeStore<USERKEY,STOREKEY,VALUE>

store

public void store(STOREKEY key,
                  VALUE value)

Store user data. If an object already exists at the key, it should be replaced.

Specified by:

store in interface NodeStore<USERKEY,STOREKEY,VALUE>