com.exonum.binding.core.storage.database

Class Fork

java.lang.Object

com.exonum.binding.core.proxy.AbstractNativeProxy

com.exonum.binding.core.storage.database.View

com.exonum.binding.core.storage.database.Fork

public final class Fork
extends View

A fork is a database view, allowing both read and write operations.

A fork represents the database state at the time it was created plus any changes to the database made using this fork.

A fork allows to perform a transaction: a number of independent writes to the database, which then may be atomically applied (i.e. committed) to the database and change the database state.

Field Summary

Fields inherited from class com.exonum.binding.core.proxy.AbstractNativeProxy

nativeHandle

Method Summary

Modifier and Type	Method and Description
void	createCheckpoint() Creates in-memory checkpoint of the current state of this Fork.
Cleaner	getCleaner() Returns the cleaner of this view.
static Fork	newInstance(long nativeHandle, boolean owningHandle, Cleaner cleaner) Creates a new Fork proxy.
static Fork	newInstance(long nativeHandle, Cleaner cleaner) Creates a new owning Fork proxy.
void	rollback() Rollbacks changes to the latest checkpoint.

Methods inherited from class com.exonum.binding.core.storage.database.View

canModify, findOpenIndex, getViewNativeHandle, registerIndex

Methods inherited from class com.exonum.binding.core.proxy.AbstractNativeProxy

getNativeHandle, isValidHandle

Methods inherited from class java.lang.Object

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

Method Detail

newInstance

public static Fork newInstance(long nativeHandle,
                               Cleaner cleaner)

Creates a new owning Fork proxy.

Parameters:

nativeHandle - a handle of the native Fork object

cleaner - a cleaner to perform any operations

newInstance

public static Fork newInstance(long nativeHandle,
                               boolean owningHandle,
                               Cleaner cleaner)

Creates a new Fork proxy.

Parameters:

nativeHandle - a handle of the native Fork object

owningHandle - whether a proxy owns the corresponding native object and is responsible to clean it up

cleaner - a cleaner to destroy this fork and any dependent objects

getCleaner

public Cleaner getCleaner()

Description copied from class: View

Returns the cleaner of this view. It is supposed to be used with collections and other objects depending on this view.

Specified by:

getCleaner in class View

createCheckpoint

public void createCheckpoint()

Creates in-memory checkpoint of the current state of this Fork. A checkpoint allows to restore the state of the Fork by reverting the changes made since the last checkpoint operation with rollback(). The changes made before the last checkpoint cannot be reverted, because each new checkpoint replaces the previous: checkpoints are not stacked.

Creating a checkpoint will invalidate all collections that were instantiated with this fork.

This operation is not intended to be used by services.

rollback

public void rollback()

Rollbacks changes to the latest checkpoint. If no checkpoints were created, rollbacks all changes made by this fork. Rollback affects only changes made with this particular Fork instance.

Rollback will invalidate all collections that were created with this fork.

This operation is not intended to be used by services.