Module org.apache.jena.arq
Package org.apache.jena.sparql.core

Class DatasetGraphWrapper

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, DatasetGraphRDFS, DatasetGraphReadOnly
public class DatasetGraphWrapper extends Object implements DatasetGraph, org.apache.jena.atlas.lib.Sync

  • Constructor Details

    • 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 Details

    • getWrapped

      public final DatasetGraph getWrapped()
      Return the DatasetGraph being wrapped.

    • getBase

      public final DatasetGraph getBase()
      Recursively unwrap a DatasetGraphWrapper.

      Note 1: Some use of DatasetGraphWrapper does not use the wrapped dataset stored in this object.

      Note 2: TDB datasets require a transaction to unwrap.

      Returns:
      the first found DatasetGraph that is not an instance of DatasetGraphWrapper

    • unwrap

      public static DatasetGraph unwrap(DatasetGraph dsg)
      Unwrap a DatasetGraph to find the base DatasetGraph. Calls getBase() if the argument is a DatasetGraphWrapper.

      Note 1: Some use of DatasetGraphWrapper does not use the wrapped dataset stored in this object.

      Note 2: TDB datasets require a transaction to unwrap.

    • 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. 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:

    • 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

    • prefixes

      public PrefixMap prefixes()
      Description copied from interface: DatasetGraph
      Prefixes for this DatasetGraph
      Specified by:
      prefixes 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:

    • 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:

    • 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:

    • 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