DatasetGraphWrapper (Apache Jena ARQ)

java.lang.Object
- org.apache.jena.sparql.core.DatasetGraphWrapper

All Implemented Interfaces:

org.apache.jena.atlas.lib.Closeable, org.apache.jena.atlas.lib.Sync, DatasetGraph, Transactional

Direct Known Subclasses:

DatasetGraphMonitor, DatasetGraphReadOnly, DatasetGraphViewGraphs, GraphStoreBasic
```
public class DatasetGraphWrapper
extends Object
implements DatasetGraph, org.apache.jena.atlas.lib.Sync
```

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.jena.sparql.core.Transactional
  Transactional.Promote

Constructor Summary

Constructors
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`.

Method Summary

All Methods Instance Methods Concrete Methods
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)`.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - DatasetGraphWrapper
```
public DatasetGraphWrapper(DatasetGraph dsg)
```
    Create a operations wrapper around dsg. The Context of the wrapper is the context of the dsg.
  - DatasetGraphWrapper
```
public DatasetGraphWrapper(DatasetGraph dsg,
                           Context context)
```
    Create a operations wrapper around dsg with context.
- Method Detail
  - getWrapped
```
public final DatasetGraph getWrapped()
```
    Return the DatasetGraph being wrapped.
  - getBase
```
public final DatasetGraph getBase()
```
    Recursively unwrap a DatasetGraphWrapper.
    
    Returns:
    
    the first found DatasetGraph that is not an instance of DatasetGraphWrapper
  - getBaseForQuery
```
public final DatasetGraph getBaseForQuery()
```
    Recursively unwrap a DatasetGraphWrapper, stopping at a DatasetGraphWrapper that indicate it is "view changing", ie shows quads to the base dataset graph.
    
    Returns:
    
    the first found DatasetGraph that is not an instance of DatasetGraphWrapper
  - containsGraph
```
public boolean containsGraph(Node graphNode)
```
    Description copied from interface: DatasetGraph
    
    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. Some datasets are "open" - they have all graphs even if no triples and this returns true always.
    
    Specified by:
    
    containsGraph in interface DatasetGraph
    
    Returns:
    
    boolean
  - getDefaultGraph
```
public Graph getDefaultGraph()
```
    Description copied from interface: DatasetGraph
    
    Get the default graph as a Jena Graph
    
    Specified by:
    
    getDefaultGraph in interface DatasetGraph
  - getUnionGraph
```
public Graph getUnionGraph()
```
    Description copied from interface: DatasetGraph
    
    Return a 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).
    
    Specified by:
    
    getUnionGraph in interface DatasetGraph
  - getGraph
```
public Graph getGraph(Node graphNode)
```
    Description copied from interface: DatasetGraph
    
    Get the graph named by graphNode : returns null when there is no such graph. NB Whether a dataset contains a graph if there are no triples is not defined - see the specific implementation. Some datasets are "open" - they have all graphs even if no triples.
    
    Specified by:
    
    getGraph in interface DatasetGraph
  - addGraph
```
public void addGraph(Node graphName,
                     Graph graph)
```
    Description copied from interface: DatasetGraph
    
    Add the given graph to the dataset. Replaces any existing data for the named graph; to add data, get the graph and add triples to it, or add quads to the dataset. Do not assume that the same Java object is returned by DatasetGraph.getGraph(org.apache.jena.graph.Node)
    
    Specified by:
    
    addGraph in interface DatasetGraph
  - removeGraph
```
public void removeGraph(Node graphName)
```
    Description copied from interface: DatasetGraph
    
    Remove all data associated with the named graph. This will include prefixes associated with the graph.
    
    Specified by:
    
    removeGraph in interface DatasetGraph
  - setDefaultGraph
```
public void setDefaultGraph(Graph g)
```
    Description copied from interface: DatasetGraph
    
    Set the default graph. Set the active graph if it was null. This replaces the contents default graph, not merge data into it. Do not assume that the same object is returned by DatasetGraph.getDefaultGraph()
    
    Specified by:
    
    setDefaultGraph in interface DatasetGraph
  - getLock
```
public Lock getLock()
```
    Description copied from interface: DatasetGraph
    
    Return a lock for the dataset to help with concurrency control
    
    Specified by:
    
    getLock in interface DatasetGraph
    
    See Also:
    
    Lock
  - listGraphNodes
```
public Iterator<Node> listGraphNodes()
```
    Description copied from interface: DatasetGraph
    
    Iterate over all names of named graphs
    
    Specified by:
    
    listGraphNodes in interface DatasetGraph
  - add
```
public void add(Quad quad)
```
    Description copied from interface: DatasetGraph
    
    Add a quad
    
    Specified by:
    
    add in interface DatasetGraph
  - delete
```
public void delete(Quad quad)
```
    Description copied from interface: DatasetGraph
    
    Delete a quad
    
    Specified by:
    
    delete in interface DatasetGraph
  - add
```
public void add(Node g,
                Node s,
                Node p,
                Node o)
```
    Description copied from interface: DatasetGraph
    
    Add a quad
    
    Specified by:
    
    add in interface DatasetGraph
  - delete
```
public void delete(Node g,
                   Node s,
                   Node p,
                   Node o)
```
    Description copied from interface: DatasetGraph
    
    Delete a quad
    
    Specified by:
    
    delete in interface DatasetGraph
  - deleteAny
```
public void deleteAny(Node g,
                      Node s,
                      Node p,
                      Node o)
```
    Description copied from interface: DatasetGraph
    
    Delete any quads matching the pattern
    
    Specified by:
    
    deleteAny in interface DatasetGraph
  - clear
```
public void clear()
```
    Description copied from interface: DatasetGraph
    
    Remove everything - remove all named graphs, clear the default graph
    
    Specified by:
    
    clear in interface DatasetGraph
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: DatasetGraph
    
    Test whether the dataset is empty
    
    Specified by:
    
    isEmpty in interface DatasetGraph
  - find
```
public Iterator<Quad> find()
```
    Description copied from interface: DatasetGraph
    
    Iterate over all quads in the dataset graph
    
    Specified by:
    
    find in interface DatasetGraph
  - find
```
public Iterator<Quad> find(Quad quad)
```
    Description copied from interface: DatasetGraph
    
    Find matching quads in the dataset - may include wildcards, Node.ANY or null
    
    Specified by:
    
    find in interface DatasetGraph
    
    See Also:
    
    Graph.find(Triple)
  - find
```
public Iterator<Quad> find(Node g,
                           Node s,
                           Node p,
                           Node o)
```
    Description copied from interface: DatasetGraph
    
    Find matching quads in the dataset (including default graph) - may include wildcards, Node.ANY or null
    
    Specified by:
    
    find in interface DatasetGraph
    
    See Also:
    
    Graph.find(Node,Node,Node)
  - findNG
```
public Iterator<Quad> findNG(Node g,
                             Node s,
                             Node p,
                             Node o)
```
    Description copied from interface: DatasetGraph
    
    Find matching quads in the dataset in named graphs only - may include wildcards, Node.ANY or null
    
    Specified by:
    
    findNG in interface DatasetGraph
    
    See Also:
    
    Graph.find(Node,Node,Node)
  - contains
```
public boolean contains(Quad quad)
```
    Description copied from interface: DatasetGraph
    
    Test whether the dataset contains a quad (including default graph)- may include wildcards, Node.ANY or null
    
    Specified by:
    
    contains in interface DatasetGraph
  - contains
```
public boolean contains(Node g,
                        Node s,
                        Node p,
                        Node o)
```
    Description copied from interface: DatasetGraph
    
    Test whether the dataset (including default graph) contains a quad - may include wildcards, Node.ANY or null
    
    Specified by:
    
    contains in interface DatasetGraph
  - getContext
```
public Context getContext()
```
    Description copied from interface: DatasetGraph
    
    Get the context associated with this object - may be null
    
    Specified by:
    
    getContext in interface DatasetGraph
  - size
```
public long size()
```
    Description copied from interface: DatasetGraph
    
    Get the size (number of named graphs) - may be -1 for unknown
    
    Specified by:
    
    size in interface DatasetGraph
  - close
```
public void close()
```
    Description copied from interface: DatasetGraph
    
    Close the dataset
    
    Specified by:
    
    close in interface org.apache.jena.atlas.lib.Closeable
    
    Specified by:
    
    close in interface DatasetGraph
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - sync
```
public void sync()
```
    Specified by:
    
    sync in interface org.apache.jena.atlas.lib.Sync
  - begin
```
public void begin()
```
    Description copied from interface: Transactional
    
    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.
    See Transactional.begin(TxnType) for more details an options.
    May not be implemented. See Transactional.begin(ReadWrite) is guaranteed to be provided.
    
    Specified by:
    
    begin in interface Transactional
  - transactionMode
```
public ReadWrite transactionMode()
```
    Description copied from interface: Transactional
    
    Return the current mode of the transaction - "read" or "write". If the caller is not in a transaction, this method returns null.
    
    Specified by:
    
    transactionMode in interface Transactional
  - transactionType
```
public TxnType transactionType()
```
    Description copied from interface: Transactional
    
    Return the transaction type used in begin(TxnType). If the caller is not in a transaction, this method returns null.
    
    Specified by:
    
    transactionType in interface Transactional
  - begin
```
public void begin(TxnType type)
```
    Description copied from interface: Transactional
    Start a transaction.
    READ or WRITE transactions start in that state and do not change for the lifetime of the transaction.
    - 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.
    Read committed: at the point transaction attempts promotion from "read" to "write", the system checks if the dataset has change since the transaction started (called 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.
    Specified by:
    
    begin in interface Transactional
  - begin
```
public void begin(ReadWrite readWrite)
```
    Description copied from interface: Transactional
    
    Start either a READ or WRITE transaction.
    
    Specified by:
    
    begin in interface Transactional
  - promote
```
public boolean promote()
```
    Description copied from interface: Transactional
    
    Attempt to promote a transaction from "read" to "write" when the transaction started with a "promote" mode (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.
    
    Specified by:
    
    promote in interface Transactional
  - promote
```
public boolean promote(Transactional.Promote type)
```
    Description copied from interface: Transactional
    
    Attempt to promote a transaction from "read" mode to "write" and the transaction. This method allows the form of promotion to be specified. The transaction must not have been started with 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.
    
    Specified by:
    
    promote in interface Transactional
  - commit
```
public void commit()
```
    Description copied from interface: Transactional
    
    Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
    
    Specified by:
    
    commit in interface Transactional
  - abort
```
public void abort()
```
    Description copied from interface: Transactional
    
    Abort a transaction - finish the transaction and undo any changes (if a "write" transaction)
    
    Specified by:
    
    abort in interface Transactional
  - end
```
public void end()
```
    Description copied from interface: Transactional
    
    Finish the transaction - if a write transaction and commit() has not been called, then abort
    
    Specified by:
    
    end in interface Transactional
  - isInTransaction
```
public boolean isInTransaction()
```
    Description copied from interface: Transactional
    
    Say whether inside a transaction.
    
    Specified by:
    
    isInTransaction in interface Transactional
  - supportsTransactions
```
public boolean supportsTransactions()
```
    Description copied from interface: DatasetGraph
    
    A DatasetGraph supports transactions if it provides Transactional.begin()/ Transactional.commit()/Transactional.end(). The core storage DatasetGraphs 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.
    
    Specified by:
    
    supportsTransactions in interface DatasetGraph
  - supportsTransactionAbort
```
public boolean supportsTransactionAbort()
```
    Description copied from interface: DatasetGraph
    
    Declare whether Transactional.abort() is supported. This goes along with clearing up after exceptions inside application transaction code.
    
    Specified by:
    
    supportsTransactionAbort in interface DatasetGraph

Class DatasetGraphWrapper

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.jena.sparql.core.Transactional

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DatasetGraphWrapper

DatasetGraphWrapper

Method Detail

getWrapped

getBase

getBaseForQuery

containsGraph

getDefaultGraph

getUnionGraph

getGraph

addGraph

removeGraph

setDefaultGraph

getLock

listGraphNodes

add

delete

add

delete

deleteAny

clear

isEmpty

find

find

find

findNG

contains

contains

getContext

size

close

toString

sync

begin

transactionMode

transactionType

begin

begin

promote

promote

commit

abort

end

isInTransaction

supportsTransactions

supportsTransactionAbort