com.avaje.ebean.config.dbplatform

Class SequenceIdGenerator

java.lang.Object

com.avaje.ebean.config.dbplatform.SequenceIdGenerator

All Implemented Interfaces:

PlatformIdGenerator

Direct Known Subclasses:

DB2SequenceIdGenerator, H2SequenceIdGenerator, OracleSequenceIdGenerator, PostgresSequenceIdGenerator

public abstract class SequenceIdGenerator
extends Object
implements PlatformIdGenerator

Database sequence based IdGenerator.

Field Summary

Fields

Modifier and Type	Field and Description
protected BackgroundExecutor	backgroundExecutor
protected Object	backgroundLoadMonitor Used to synchronise background loading (loadBatchInBackground).
protected int	batchSize
protected int	currentlyBackgroundLoading
protected DataSource	dataSource
protected ArrayList<Long>	idList
protected Object	monitor Used to synchronise the idList access.
protected String	seqName The actual sequence name.

Fields inherited from interface com.avaje.ebean.config.dbplatform.PlatformIdGenerator

AUTO_UUID

Constructor Summary

Constructors

Constructor and Description
SequenceIdGenerator(BackgroundExecutor be, DataSource ds, String seqName, int batchSize) Construct given a dataSource and sql to return the next sequence value.

Method Summary

Modifier and Type	Method and Description
protected void	closeResources(Connection c, PreparedStatement pstmt, ResultSet rset) Close the JDBC resources.
protected ArrayList<Long>	getMoreIds(int loadSize, Transaction t) Get more Id's by executing a query and reading the Id's returned.
String	getName() Returns the sequence name.
abstract String	getSql(int batchSize)
boolean	isDbSequence() Returns true.
protected void	loadBatchInBackground() Load another batch of Id's using a background thread.
protected void	loadLargeAllocation(int allocateSize) Called by preAllocateIds when we know that a large number of Id's is going to be needed shortly.
protected void	loadMoreIds(int numberToLoad, Transaction t)
Object	nextId(Transaction t) Return the next Id.
void	preAllocateIds(int allocateSize) If allocateSize is large load some sequences in a background thread.

Methods inherited from class java.lang.Object

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

Field Detail

monitor

protected final Object monitor

Used to synchronise the idList access.

backgroundLoadMonitor

protected final Object backgroundLoadMonitor

Used to synchronise background loading (loadBatchInBackground).

seqName

protected final String seqName

The actual sequence name.

dataSource

protected final DataSource dataSource

backgroundExecutor

protected final BackgroundExecutor backgroundExecutor

idList

protected final ArrayList<Long> idList

batchSize

protected final int batchSize

currentlyBackgroundLoading

protected int currentlyBackgroundLoading

Constructor Detail

SequenceIdGenerator

public SequenceIdGenerator(BackgroundExecutor be,
                           DataSource ds,
                           String seqName,
                           int batchSize)

Construct given a dataSource and sql to return the next sequence value.

Method Detail

getSql

public abstract String getSql(int batchSize)

getName

public String getName()

Returns the sequence name.

Specified by:

getName in interface PlatformIdGenerator

isDbSequence

public boolean isDbSequence()

Returns true.

Specified by:

isDbSequence in interface PlatformIdGenerator

preAllocateIds

public void preAllocateIds(int allocateSize)

If allocateSize is large load some sequences in a background thread.

For example, when inserting a bean with a cascade on a OneToMany with many beans Ebean can call this to ensure .

Specified by:

preAllocateIds in interface PlatformIdGenerator

loadLargeAllocation

protected void loadLargeAllocation(int allocateSize)

Called by preAllocateIds when we know that a large number of Id's is going to be needed shortly.

nextId

public Object nextId(Transaction t)

Return the next Id.

If a Transaction has been passed in use the Connection from it.

Specified by:

nextId in interface PlatformIdGenerator

loadBatchInBackground

protected void loadBatchInBackground()

Load another batch of Id's using a background thread.

loadMoreIds

protected void loadMoreIds(int numberToLoad,
                           Transaction t)

getMoreIds

protected ArrayList<Long> getMoreIds(int loadSize,
                                     Transaction t)

Get more Id's by executing a query and reading the Id's returned.

closeResources

protected void closeResources(Connection c,
                              PreparedStatement pstmt,
                              ResultSet rset)

Close the JDBC resources.