io.goshawkdb.client

Interface Transaction

public interface Transaction

An object of this type is supplied to TransactionFunctions to provide access to the object graph stored by GoshawkDB. Transaction must not be used outside of a transaction.

Method Summary

Modifier and Type	Method and Description
GoshawkObjRef	createObject(java.nio.ByteBuffer value, GoshawkObjRef... references) Create a new object and set its value and references.
GoshawkObjRef	getObject(GoshawkObjRef objRef) Fetches the object specified by a reference.
java.util.Map<java.lang.String,GoshawkObjRef>	getRoots() Get the roots of the object-graph.
void	retry() Perform a retry operation.

Method Detail

retry

void retry()

Perform a retry operation. The set of objects read from in the transaction so far is determined, and the thread is blocked until some other transaction modifies any of these objects. At this point, the transaction will be automatically restarted in the same thread.

getRoots

java.util.Map<java.lang.String,GoshawkObjRef> getRoots()

Get the roots of the object-graph. The Root Objects for each client are defined by the cluster configuration and represent the roots of the object graphs. For an object to be reachable, the client must be able to discover and read a path to it from a root object.

Returns:

References to the Root Objects.

createObject

GoshawkObjRef createObject(java.nio.ByteBuffer value,
                           GoshawkObjRef... references)

Create a new object and set its value and references. The client creating an object will be granted full ReadWrite Capability on the object for the lifetime of the client connection.

Parameters:

value - The value to set the new object to. The buffer will be cloned and the contents copied. Therefore any changes you make to this param after calling this method will be ignored (you will need to call a set method). The copying will not alter any position, limit, capacity or marks of the value ByteBuffer. The value is taken to be from position 0 to the current limit of the buffer.

references - The list of objects to which the new object refers. Again, the array of references is copied.

Returns:

The new object

getObject

GoshawkObjRef getObject(GoshawkObjRef objRef)

Fetches the object specified by a reference. Note this will fail unless the client has already navigated the object graph at least as far as any object that has a reference to the object reference provided. This method is not normally necessary: it is generally preferred to use the References of objects to navigate.

Parameters:

objRef - Reference of the object to retrieve

Returns:

The object. The same object ref provided is returned but it is updated as necessary to a valid object. Note that this method does not validate the capability embedded within the reference is valid.