public class DatasetGraphOne extends DatasetGraphBaseFind
Fixed as one graph (the default) - named graphs can notbe added nor the default graph changed, only the contents modified.
Ths dataset passes transactions down to a nominated backing DatasetGraph
It is particular suitable for use with an interference graph.
Transactional.Promote
Modifier and Type | Method and Description |
---|---|
void |
abort()
Abort a transaction - finish the transaction and undo any changes (if a "write" transaction)
|
void |
add(Node g,
Node s,
Node p,
Node o)
Add a quad
|
void |
add(Quad quad)
Add a quad
|
void |
addGraph(Node graphName,
Graph graph)
Add the given graph to the dataset.
|
void |
begin(ReadWrite mode)
Start either a READ or WRITE transaction.
|
void |
begin(TxnType txnType)
Start a transaction.
READ or WRITE transactions start in that state and do not change for the lifetime of the transaction. |
void |
close()
Close the dataset
|
void |
commit()
Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
|
boolean |
containsGraph(Node graphNode)
Does the DatasetGraph contain a specific named graph?
Whether a dataset contains a graph if there are no triples is
not defined - see the specific implementation.
|
static DatasetGraph |
create(Graph graph) |
void |
delete(Node g,
Node s,
Node p,
Node o)
Delete a quad
|
void |
delete(Quad quad)
Delete a quad
|
void |
end()
Finish the transaction - if a write transaction and commit() has not been called, then abort
|
Iterator<Quad> |
find(Node g,
Node s,
Node p,
Node o)
Implementation of find based on splitting into triples (default graph) and quads (named graph)
|
Graph |
getDefaultGraph()
Get the default graph as a Jena Graph
|
Graph |
getGraph(Node graphNode)
Get the graph named by graphNode : returns null when there is no such graph.
|
Graph |
getUnionGraph()
Return a
Graph that is the union of all named graphs in this dataset. |
boolean |
isInTransaction()
Say whether inside a transaction.
|
Iterator<Node> |
listGraphNodes()
Iterate over all names of named graphs
|
boolean |
promote(Transactional.Promote txnType)
Attempt to promote a transaction from "read" mode to "write" and the transaction.
|
void |
removeGraph(Node graphName)
Remove all data associated with the named graph.
|
void |
setDefaultGraph(Graph g)
Set the default graph.
|
long |
size()
Get the size (number of named graphs) - may be -1 for unknown
|
boolean |
supportsTransactionAbort()
Declare whether
Transactional.abort() is supported. |
boolean |
supportsTransactions()
A
DatasetGraph supports transactions if it provides Transactional.begin() /
Transactional.commit() /Transactional.end() . |
ReadWrite |
transactionMode()
Return the current mode of the transaction - "read" or "write".
|
TxnType |
transactionType()
Return the transaction type used in
begin(TxnType) . |
findInUnionGraph, findNG, findQuadsInUnionGraph
clear, contains, contains, deleteAny, deleteAny, find, find, getContext, getLock, isEmpty, toString
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
begin, promote
public static DatasetGraph create(Graph graph)
public void begin(TxnType txnType)
Transactional
WRITE
: this guarantees a WRITE will complete if commit()
is
called. The same as begin(ReadWrite.WRITE)
.
READ
: the transaction can not promote to WRITE,ensuring read-only
access to the data. The same as begin(ReadWrite.READ)
.
READ_PROMOTE
: the transaction will go from "read" to "write" if an
update is attempted and if the dataset has not been changed by another write
transaction. See also Transactional.promote()
.
READ_COMMITTED_PROMOTE
: Use this with care. The promotion will
succeed but changes from other transactions become visible.
begin
). If READ_PROMOTE
, the dataset must not have
changed; if READ_COMMITTED_PROMOTE
any intermediate changes are
visible but the application can not assume any data it has read in the
transaction is the same as it was at the point the transaction started.
This operation is optional and some implementations may throw
a JenaTransactionException
exception for some or all TxnType
values.
See Transactional.begin(ReadWrite)
for a form that is required of implementations.
public void begin(ReadWrite mode)
Transactional
public void commit()
Transactional
public boolean promote(Transactional.Promote txnType)
Transactional
READ
, which is read-only.
An argument of READ_PROMOTE
treats the promotion as if the transaction was started
with READ_PROMOTE
(any other writer commiting since the transaction started
blocks promotion) and READ_COMMITTED_PROMOTE
treats the promotion as if the transaction was started
with READ_COMMITTED_PROMOTE
(intemediate writer commits become visible).
Returns "true" if the transaction is in write mode after the call. The method always succeeds of the transaction is already "write".
This method returns true if a READ_PROMOTE
or
READ_COMMITTED_PROMOTE
is promoted.
This method returns false if a READ_PROMOTE
can't be promoted - the
transaction is still valid and in "read" mode.
This method throws an exception if there is an attempt to promote a READ
transaction.
public void abort()
Transactional
public boolean isInTransaction()
Transactional
public void end()
Transactional
public ReadWrite transactionMode()
Transactional
public TxnType transactionType()
Transactional
begin(TxnType)
.
If the caller is not in a transaction, this method returns null.public boolean supportsTransactions()
DatasetGraph
DatasetGraph
supports transactions if it provides Transactional.begin()
/
Transactional.commit()
/Transactional.end()
. The core storage DatasetGraph
s
provide fully serialized transactions. A DatasetGraph
that provides
functionality across independent systems can not provide such strong guarantees.
For example, it may use MRSW locking and some isolation control.
Specifically, it would not necessarily provide Transactional.abort()
.
See DatasetGraph.supportsTransactionAbort()
for Transactional.abort()
.
In addition, check details of a specific implementation.
public boolean supportsTransactionAbort()
DatasetGraph
Transactional.abort()
is supported.
This goes along with clearing up after exceptions inside application transaction code.public boolean containsGraph(Node graphNode)
DatasetGraph
containsGraph
in interface DatasetGraph
containsGraph
in class DatasetGraphBase
public Graph getDefaultGraph()
DatasetGraph
getDefaultGraph
in interface DatasetGraph
getDefaultGraph
in class DatasetGraphBase
public Graph getUnionGraph()
DatasetGraph
Graph
that is the union of all named graphs in this dataset. This
union graph is read-only (its prefix mapping in the current JVM may be changed but
that may not persist).getUnionGraph
in interface DatasetGraph
getUnionGraph
in class DatasetGraphBase
public Graph getGraph(Node graphNode)
DatasetGraph
getGraph
in interface DatasetGraph
getGraph
in class DatasetGraphBase
public Iterator<Node> listGraphNodes()
DatasetGraph
public long size()
DatasetGraph
size
in interface DatasetGraph
size
in class DatasetGraphBase
public void add(Node g, Node s, Node p, Node o)
DatasetGraph
add
in interface DatasetGraph
add
in class DatasetGraphBase
public void add(Quad quad)
DatasetGraph
add
in interface DatasetGraph
add
in class DatasetGraphBase
public void delete(Node g, Node s, Node p, Node o)
DatasetGraph
delete
in interface DatasetGraph
delete
in class DatasetGraphBase
public void delete(Quad quad)
DatasetGraph
delete
in interface DatasetGraph
delete
in class DatasetGraphBase
public void setDefaultGraph(Graph g)
DatasetGraph
DatasetGraph.getDefaultGraph()
setDefaultGraph
in interface DatasetGraph
setDefaultGraph
in class DatasetGraphBase
public void addGraph(Node graphName, Graph graph)
DatasetGraph
DatasetGraph.getGraph(org.apache.jena.graph.Node)
addGraph
in interface DatasetGraph
addGraph
in class DatasetGraphBase
public void removeGraph(Node graphName)
DatasetGraph
removeGraph
in interface DatasetGraph
removeGraph
in class DatasetGraphBase
public Iterator<Quad> find(Node g, Node s, Node p, Node o)
DatasetGraphBaseFind
find
in interface DatasetGraph
find
in class DatasetGraphBaseFind
Graph.find(Node,Node,Node)
public void close()
DatasetGraph
close
in interface org.apache.jena.atlas.lib.Closeable
close
in interface DatasetGraph
close
in class DatasetGraphBase
Licenced under the Apache License, Version 2.0