org.neo4j.kernel.impl.transaction.xaframework
Class XaDataSource

java.lang.Object
  org.neo4j.kernel.impl.transaction.xaframework.XaDataSource

Direct Known Subclasses:

LogBackedXaDataSource

public abstract class XaDataSource
extends Object

XaDataSource is as a factory for creating XaConnections.

If you're writing a data source towards a XA compatible resource the implementation should be fairly straight forward. This will basically be a factory for your XaConnections that in turn will wrap the XA compatible XAResource.

If you're writing a data source towards a non XA compatible resource use the XaContainer and extend the XaConnectionHelpImpl as your XaConnection implementation. Here is an example:

 
 public class MyDataSource implements XaDataSource {
     MyDataSource( params ) {
         // ... initalization stuff
         container = XaContainer.create( myLogicalLogFile, myCommandFactory,
             myTransactionFactory );
         // ... more initialization stuff
         container.openLogicalLog();
     }
     public XaConnection getXaCo nnection() {
         return new MyXaConnection( params );
     }
     public void close() {
         // ... cleanup
         container.close();
     }
 }
 
 

Constructor Summary

XaDataSource(Map<?,?> params)
Constructor used by the Neo4j kernel to create datasources.

Method Summary

void	applyCommittedTransaction(long txId, ReadableByteChannel transaction)
long	applyPreparedTransaction(ReadableByteChannel transaction)
abstract void	close() Closes this data source.
boolean	deleteLogicalLog(long version) Deletes a log specific logical log.
byte[]	getBranchId() Returns any assigned or default branch id for this data source.
long	getCreationTime() Returns a timestamp when this data source was created.
long	getCurrentLogVersion() Returns the current version of this data source.
String	getFileName(long version)
long	getLastCommittedTxId()
LogExtractor	getLogExtractor(long startTxId, long endTxIdHint)
ReadableByteChannel	getLogicalLog(long version) Returns a readable byte channel of the specified logical log.
long	getLogicalLogLength(long version)
Pair<Integer,Long>	getMasterForCommittedTx(long txId)
String	getName() Returns the assigned name of this resource.
ReadableByteChannel	getPreparedTransaction(int identifier)
void	getPreparedTransaction(int identifier, LogBuffer targetBuffer)
long	getRandomIdentifier() Returns a random identifier that gets generated when the data source is created.
abstract XaConnection	getXaConnection() Creates a XA connection to the resource this data source represents.
XaContainer	getXaContainer()
boolean	hasLogicalLog(long version) Tests if a specific logical log exists.
boolean	isLogicalLogKept()
void	keepLogicalLogs(boolean keepLogs) Sets wether logical logs should be saved upon rotation or not.
ClosableIterable<File>	listStoreFiles(boolean includeLogicalLogs)
long	rotateLogicalLog() Rotates this logical log.
void	setAutoRotate(boolean rotate) Turns off/on auto rotate of logical logs.
void	setBranchId(byte[] branchId) Used by the container/transaction manager in place to assign a branch id for this data source.
void	setLastCommittedTxId(long txId)
void	setLogicalLogTargetSize(long size) Sets the target size of the logical log that will cause a rotation of the log if setAutoRotate(boolean) is set to true.
void	setName(String name) Used by the container to assign a name to this resource.
boolean	setRecovered(boolean recovered) Returns previous value
protected Boolean	shouldKeepLog(String config, String resourceName) If the config says that logical logs should be kept for the given resourceName this method will return true, otherwise false.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XaDataSource

public XaDataSource(Map<?,?> params)
             throws InstantiationException

Constructor used by the Neo4j kernel to create datasources.

Parameters:

params - A map containing configuration parameters

Throws:

InstantiationException

Method Detail

getXaConnection

public abstract XaConnection getXaConnection()

Creates a XA connection to the resource this data source represents.

Returns:

A connection to an XA resource

close

public abstract void close()

Closes this data source. Calling getXaConnection after this method has been invoked is illegal.

setBranchId

public void setBranchId(byte[] branchId)

Used by the container/transaction manager in place to assign a branch id for this data source.

Parameters:

branchId - the branch id

getBranchId

public byte[] getBranchId()

Returns any assigned or default branch id for this data source.

Returns:

the branch id

getCreationTime

public long getCreationTime()

Returns a timestamp when this data source was created. Note this is not the timestamp for the creation of the data source object instance, if the data source is for example a database timestamp is meant to be when the database was created.

Creation time together with random identifier can be used to uniqley identify a data source (since it is possible to have multiple sources of same type).

Returns:

timestamp when this datasource was created

getFileName

public String getFileName(long version)

getRandomIdentifier

public long getRandomIdentifier()

Returns a random identifier that gets generated when the data source is created. Note with "created" we mean first time data source is created and not object creation.

Creation time together with the random identifier can be used to uniquely identify a data source (since it is possible to have multiple sources of the same type).

Returns:

random identifier for this data source

getCurrentLogVersion

public long getCurrentLogVersion()

Returns the current version of this data source. A invoke to the rotateLogicalLog() when keepLogicalLogs(boolean) is set to true will result in a log with that version created.

Returns:

the current version of the logical log

rotateLogicalLog

public long rotateLogicalLog()
                      throws IOException

Rotates this logical log. If keepLogicalLogs(boolean) is configured to true the log will be saved and can be retrieved with the getLogicalLog(long) method. If not it will be deleted. Active transactions get copied to a new logical log.

Throws:

IOException - if unable to read old log or write to new one

getLogicalLog

public ReadableByteChannel getLogicalLog(long version)
                                  throws IOException

Returns a readable byte channel of the specified logical log.

Parameters:

version - version of the logical log

Returns:

readable byte channel of the logical log

Throws:

IOException - if no such log exist

hasLogicalLog

public boolean hasLogicalLog(long version)

Tests if a specific logical log exists.

Parameters:

version - the version of the logical log

Returns:

true if the log exists

getLogicalLogLength

public long getLogicalLogLength(long version)

deleteLogicalLog

public boolean deleteLogicalLog(long version)

Deletes a log specific logical log.

Parameters:

version - version of log to delete

Returns:

true if the log existed and was deleted

keepLogicalLogs

public void keepLogicalLogs(boolean keepLogs)

Sets wether logical logs should be saved upon rotation or not. Default is false.

Parameters:

keepLogs - true means save, false means delete

isLogicalLogKept

public boolean isLogicalLogKept()

setName

public void setName(String name)

Used by the container to assign a name to this resource.

Parameters:

name - name of this resource

getName

public String getName()

Returns the assigned name of this resource.

Returns:

the assigned name of this resource

setAutoRotate

public void setAutoRotate(boolean rotate)

Turns off/on auto rotate of logical logs. Default is true.

Parameters:

rotate - true to turn on

setLogicalLogTargetSize

public void setLogicalLogTargetSize(long size)

Sets the target size of the logical log that will cause a rotation of the log if setAutoRotate(boolean) is set to true.

Parameters:

size - target size in bytes

shouldKeepLog

protected Boolean shouldKeepLog(String config,
                                String resourceName)

If the config says that logical logs should be kept for the given resourceName this method will return true, otherwise false. The format of the configuration value is either:

• = : no data sources will keep its logs
• =nioneodb,lucene : the specified data sources will keep its logs
• =true : all data sources will keep their logical logs

The first and last are recommended, since the data source names are really an implementation detail.

Parameters:

config - the configuration value specified by user configuration.

resourceName - the name of the xa data source to check.

Returns:

whether or not logical logs should be kept for the data source by the name resourceName or not. Or null if not specified.

getPreparedTransaction

public ReadableByteChannel getPreparedTransaction(int identifier)
                                           throws IOException

Throws:

IOException

getPreparedTransaction

public void getPreparedTransaction(int identifier,
                                   LogBuffer targetBuffer)
                            throws IOException

Throws:

IOException

applyCommittedTransaction

public void applyCommittedTransaction(long txId,
                                      ReadableByteChannel transaction)
                               throws IOException

Throws:

IOException

applyPreparedTransaction

public long applyPreparedTransaction(ReadableByteChannel transaction)
                              throws IOException

Throws:

IOException

getLastCommittedTxId

public long getLastCommittedTxId()

setLastCommittedTxId

public void setLastCommittedTxId(long txId)

getXaContainer

public XaContainer getXaContainer()

getMasterForCommittedTx

public Pair<Integer,Long> getMasterForCommittedTx(long txId)
                                           throws IOException

Throws:

IOException

listStoreFiles

public ClosableIterable<File> listStoreFiles(boolean includeLogicalLogs)
                                      throws IOException

Throws:

IOException

setRecovered

public boolean setRecovered(boolean recovered)

Returns previous value

getLogExtractor

public LogExtractor getLogExtractor(long startTxId,
                                    long endTxIdHint)
                             throws IOException

Throws:

IOException