org.apache.ojb.broker.util.sequence
Class SequenceManagerHighLowImpl

java.lang.Object
  org.apache.ojb.broker.util.sequence.AbstractSequenceManager
      org.apache.ojb.broker.util.sequence.SequenceManagerHighLowImpl

All Implemented Interfaces:

SequenceManager

public class SequenceManagerHighLowImpl
extends AbstractSequenceManager

High/Low sequence manager implementation generates unique and continuous id's (during runtime) by using sequences to avoid database access.

Implementation configuration properties:

Property Key	Property Values
seq.start	Set the start index of used sequences (e.g. set 100000, id generation starts with 100001). Default start index is 1.
grabSize	Integer entry determines the number of IDs allocated within the H/L sequence manager implementation. Default was '20'.
autoNaming	Default was 'true'. If set 'true' OJB try to build a sequence name automatic if none found in field-descriptor and set this generated name as sequence-name in field-descriptor. If set 'false' OJB throws an exception if none sequence name was found in field-descriptor.
globalSequenceId	Deprecated! If set 'true' implementation use global unique id's for all fields. Default was 'false'.
globalSequenceStart	Deprecated, use property 'seq.start'. Set the start index of used global id generation (e.g. set 100000, id generation starts with 100001)
sequenceStart	Deprecated, use property 'seq.start'. Set the start index of used sequences (e.g. set 100000, id generation starts with 100001). Default start index is 1.

Limitations:

• Do NOT use this implementation in managed environment or any comparable system where any connection was associated with the running transaction.

Version:

$Id: SequenceManagerHighLowImpl.java,v 1.1 2007-08-24 22:17:29 ewestfal Exp $

Author:

Armin Waibel

See Also:

SequenceManager, SequenceManagerFactory, SequenceManagerHelper

Field Summary

protected int	attempts
protected int	grabSize
static String	PROPERTY_GLOBAL_SEQUENCE_ID
static String	PROPERTY_GLOBAL_SEQUENCE_START
static String	PROPERTY_GRAB_SIZE
protected static Map	sequencesDBMap
protected long	sequenceStart
protected boolean	useGlobalSequenceIdentities

Fields inherited from class org.apache.ojb.broker.util.sequence.AbstractSequenceManager

PROPERTY_AUTO_NAMING

Constructor Summary

SequenceManagerHighLowImpl(PersistenceBroker broker)

Method Summary

protected long	getMaxKeyForSequence(PersistenceBroker broker, FieldDescriptor field)
protected HighLowSequence	getSequence(PersistenceBroker brokerForSequence, FieldDescriptor field, String sequenceName)
protected long	getUniqueLong(FieldDescriptor field) returns a unique long value for field.
protected HighLowSequence	lookupStoreSequence(PersistenceBroker broker, FieldDescriptor field, String seqName)
protected HighLowSequence	newSequenceObject(String sequenceName, FieldDescriptor field)
protected void	removeSequence(String sequenceName) Remove the sequence for given sequence name.

Methods inherited from class org.apache.ojb.broker.util.sequence.AbstractSequenceManager

afterStore, calculateSequenceName, getBrokerForClass, getConfigurationProperties, getConfigurationProperty, getPlatform, getUniqueValue, setConfigurationProperties, setConfigurationProperty, setReferenceFKs, useAutoNaming

Methods inherited from class java.lang.Object

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

Field Detail

PROPERTY_GRAB_SIZE

public static final String PROPERTY_GRAB_SIZE

See Also:

Constant Field Values

PROPERTY_GLOBAL_SEQUENCE_ID

public static final String PROPERTY_GLOBAL_SEQUENCE_ID

See Also:

Constant Field Values

PROPERTY_GLOBAL_SEQUENCE_START

public static final String PROPERTY_GLOBAL_SEQUENCE_START

See Also:

Constant Field Values

sequencesDBMap

protected static Map sequencesDBMap

useGlobalSequenceIdentities

protected boolean useGlobalSequenceIdentities

grabSize

protected int grabSize

sequenceStart

protected long sequenceStart

attempts

protected int attempts

Constructor Detail

SequenceManagerHighLowImpl

public SequenceManagerHighLowImpl(PersistenceBroker broker)

Method Detail

getUniqueLong

protected long getUniqueLong(FieldDescriptor field)
                      throws SequenceManagerException

Description copied from class: AbstractSequenceManager

returns a unique long value for field. the returned number is unique accross all tables in the extent of clazz.

Specified by:

getUniqueLong in class AbstractSequenceManager

Throws:

SequenceManagerException

removeSequence

protected void removeSequence(String sequenceName)

Remove the sequence for given sequence name.

Parameters:

sequenceName - Name of the sequence to remove.

getSequence

protected HighLowSequence getSequence(PersistenceBroker brokerForSequence,
                                      FieldDescriptor field,
                                      String sequenceName)
                               throws SequenceManagerException

Throws:

SequenceManagerException

lookupStoreSequence

protected HighLowSequence lookupStoreSequence(PersistenceBroker broker,
                                              FieldDescriptor field,
                                              String seqName)

newSequenceObject

protected HighLowSequence newSequenceObject(String sequenceName,
                                            FieldDescriptor field)

getMaxKeyForSequence

protected long getMaxKeyForSequence(PersistenceBroker broker,
                                    FieldDescriptor field)