public class DatasetGraphWrapper extends Object implements DatasetGraph, org.apache.jena.atlas.lib.Sync
Transactional.Promote
Constructor and Description |
---|
DatasetGraphWrapper(DatasetGraph dsg)
Create a operations wrapper around
dsg . |
DatasetGraphWrapper(DatasetGraph dsg,
Context context)
Create a operations wrapper around
dsg with context . |
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()
Start a transaction which is READ mode and which will switch to WRITE if an update
is attempted but only if no intermediate transaction has performed an update.
|
void |
begin(ReadWrite readWrite)
Start either a READ or WRITE transaction.
|
void |
begin(TxnType type)
Start a transaction.
READ or WRITE transactions start in that state and do not change for the lifetime of the transaction. |
void |
clear()
Remove everything - remove all named graphs, clear the default graph
|
void |
close()
Close the dataset
|
void |
commit()
Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
|
boolean |
contains(Node g,
Node s,
Node p,
Node o)
Test whether the dataset (including default graph) contains a quad - may include wildcards, Node.ANY or null
|
boolean |
contains(Quad quad)
Test whether the dataset contains a quad (including default graph)- may include wildcards, Node.ANY or null
|
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.
|
void |
delete(Node g,
Node s,
Node p,
Node o)
Delete a quad
|
void |
delete(Quad quad)
Delete a quad
|
void |
deleteAny(Node g,
Node s,
Node p,
Node o)
Delete any quads matching the pattern
|
void |
end()
Finish the transaction - if a write transaction and commit() has not been called, then abort
|
Iterator<Quad> |
find()
Iterate over all quads in the dataset graph
|
Iterator<Quad> |
find(Node g,
Node s,
Node p,
Node o)
Find matching quads in the dataset (including default graph) - may include wildcards, Node.ANY or null
|
Iterator<Quad> |
find(Quad quad)
Find matching quads in the dataset - may include wildcards, Node.ANY or null
|
Iterator<Quad> |
findNG(Node g,
Node s,
Node p,
Node o)
Find matching quads in the dataset in named graphs only - may include wildcards, Node.ANY or null
|
DatasetGraph |
getBase()
Recursively unwrap a
DatasetGraphWrapper . |
DatasetGraph |
getBaseForQuery()
Recursively unwrap a
DatasetGraphWrapper , stopping at a DatasetGraphWrapper
that indicate it is "view changing", ie shows quads to the base dataset graph. |
Context |
getContext()
Get the context associated with this object - may be null
|
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.
|
Lock |
getLock()
Return a lock for the dataset to help with concurrency control
|
Graph |
getUnionGraph()
Return a
Graph that is the union of all named graphs in this dataset. |
DatasetGraph |
getWrapped()
Return the DatasetGraph being wrapped.
|
boolean |
isEmpty()
Test whether the dataset is empty
|
boolean |
isInTransaction()
Say whether inside a transaction.
|
Iterator<Node> |
listGraphNodes()
Iterate over all names of named graphs
|
boolean |
promote()
Attempt to promote a transaction from "read" to "write" when the transaction
started with a "promote" mode (
READ_PROMOTE or
READ_COMMITTED_PROMOTE ). |
boolean |
promote(Transactional.Promote type)
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() . |
void |
sync() |
String |
toString() |
ReadWrite |
transactionMode()
Return the current mode of the transaction - "read" or "write".
|
TxnType |
transactionType()
Return the transaction type used in
begin(TxnType) . |
public DatasetGraphWrapper(DatasetGraph dsg)
public DatasetGraphWrapper(DatasetGraph dsg, Context context)
dsg
with context
.public final DatasetGraph getWrapped()
public final DatasetGraph getBase()
DatasetGraphWrapper
.DatasetGraph
that is not an instance of DatasetGraphWrapper
public final DatasetGraph getBaseForQuery()
DatasetGraphWrapper
, stopping at a DatasetGraphWrapper
that indicate it is "view changing", ie shows quads to the base dataset graph.DatasetGraph
that is not an instance of DatasetGraphWrapper
public boolean containsGraph(Node graphNode)
DatasetGraph
containsGraph
in interface DatasetGraph
public Graph getDefaultGraph()
DatasetGraph
getDefaultGraph
in interface DatasetGraph
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
public Graph getGraph(Node graphNode)
DatasetGraph
getGraph
in interface DatasetGraph
public void addGraph(Node graphName, Graph graph)
DatasetGraph
DatasetGraph.getGraph(org.apache.jena.graph.Node)
addGraph
in interface DatasetGraph
public void removeGraph(Node graphName)
DatasetGraph
removeGraph
in interface DatasetGraph
public void setDefaultGraph(Graph g)
DatasetGraph
DatasetGraph.getDefaultGraph()
setDefaultGraph
in interface DatasetGraph
public Lock getLock()
DatasetGraph
getLock
in interface DatasetGraph
Lock
public Iterator<Node> listGraphNodes()
DatasetGraph
listGraphNodes
in interface DatasetGraph
public void add(Quad quad)
DatasetGraph
add
in interface DatasetGraph
public void delete(Quad quad)
DatasetGraph
delete
in interface DatasetGraph
public void add(Node g, Node s, Node p, Node o)
DatasetGraph
add
in interface DatasetGraph
public void delete(Node g, Node s, Node p, Node o)
DatasetGraph
delete
in interface DatasetGraph
public void deleteAny(Node g, Node s, Node p, Node o)
DatasetGraph
deleteAny
in interface DatasetGraph
public void clear()
DatasetGraph
clear
in interface DatasetGraph
public boolean isEmpty()
DatasetGraph
isEmpty
in interface DatasetGraph
public Iterator<Quad> find()
DatasetGraph
find
in interface DatasetGraph
public Iterator<Quad> find(Quad quad)
DatasetGraph
find
in interface DatasetGraph
Graph.find(Triple)
public Iterator<Quad> find(Node g, Node s, Node p, Node o)
DatasetGraph
find
in interface DatasetGraph
Graph.find(Node,Node,Node)
public Iterator<Quad> findNG(Node g, Node s, Node p, Node o)
DatasetGraph
findNG
in interface DatasetGraph
Graph.find(Node,Node,Node)
public boolean contains(Quad quad)
DatasetGraph
contains
in interface DatasetGraph
public boolean contains(Node g, Node s, Node p, Node o)
DatasetGraph
contains
in interface DatasetGraph
public Context getContext()
DatasetGraph
getContext
in interface DatasetGraph
public long size()
DatasetGraph
size
in interface DatasetGraph
public void close()
DatasetGraph
close
in interface org.apache.jena.atlas.lib.Closeable
close
in interface DatasetGraph
public void sync()
sync
in interface org.apache.jena.atlas.lib.Sync
public void begin()
Transactional
See Transactional.begin(TxnType)
for more details an options.
May not be implemented. See Transactional.begin(ReadWrite)
is guaranteed to be provided.
begin
in interface Transactional
public ReadWrite transactionMode()
Transactional
transactionMode
in interface Transactional
public TxnType transactionType()
Transactional
begin(TxnType)
.
If the caller is not in a transaction, this method returns null.transactionType
in interface Transactional
public void begin(TxnType type)
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.
begin
in interface Transactional
public void begin(ReadWrite readWrite)
Transactional
begin
in interface Transactional
public boolean promote()
Transactional
READ_PROMOTE
or
READ_COMMITTED_PROMOTE
).
Returns "true" if the transaction is in write mode after the call. The method always succeeds of the transaction is already "write".
A READ_COMMITTED_PROMOTE
can always be promoted, but the call may need to
wait.
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. Any further calls to
promote()
will also return false.
This method returns false if there is an attempt to promote a "READ" transaction.
promote
in interface Transactional
public boolean promote(Transactional.Promote type)
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.
promote
in interface Transactional
public void commit()
Transactional
commit
in interface Transactional
public void abort()
Transactional
abort
in interface Transactional
public void end()
Transactional
end
in interface Transactional
public boolean isInTransaction()
Transactional
isInTransaction
in interface Transactional
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.
supportsTransactions
in interface DatasetGraph
public boolean supportsTransactionAbort()
DatasetGraph
Transactional.abort()
is supported.
This goes along with clearing up after exceptions inside application transaction code.supportsTransactionAbort
in interface DatasetGraph
Licenced under the Apache License, Version 2.0