org.jpox.metadata
Class VersionMetaData

java.lang.Object
  org.jpox.metadata.MetaData
      org.jpox.metadata.ExtendableMetaData
          org.jpox.metadata.VersionMetaData

All Implemented Interfaces:

java.io.Serializable

public class VersionMetaData
extends ExtendableMetaData

Three common strategies for versioning instances are supported by standard metadata. These include state-comparison, timestamp, and version-number. State-comparison involves comparing the values in specific columns to determine if the database row was changed. Timestamp involves comparing the value in a date-time column in the table. The first time in a transaction the row is updated, the timestamp value is updated to the current time. Version-number involves comparing the value in a numeric column in the table. The first time in a transaction the row is updated, the version-number column value is incremented.

MetaData Element

The MetaData element represented here is as follows

 <!ELEMENT version (extension*, column*, index?, extension*)>
 <!ATTLIST version strategy CDATA #IMPLIED>
 <!ATTLIST version column CDATA #IMPLIED>
 <!ATTLIST version indexed (true|false|unique) #IMPLIED>
 

Version:

$Revision: 1.7 $

See Also:

Serialized Form

Field Summary

protected ColumnMetaData[]	columnMetaData Contains the metadata for column
protected java.util.List	columns Columns ColumnMetaData
protected IndexedValue	indexed Indexed value
protected IndexMetaData	indexMetaData IndexMetaData.

Fields inherited from class org.jpox.metadata.ExtendableMetaData

extensions, JPOX_VENDOR_NAME

Fields inherited from class org.jpox.metadata.MetaData

LOCALISER, METADATA_CREATED_STATE, METADATA_INITIALISED_STATE, METADATA_POPULATED_STATE, METADATA_USED_STATE, metaDataState, parent

Constructor Summary

VersionMetaData(java.lang.String versionStrategy, java.lang.String column, java.lang.String indexed)
Constructor.

Method Summary

void	addColumn(ColumnMetaData colmd) Add a new ColumnMetaData element
ColumnMetaData[]	getColumnMetaData() Acessor for the columns
IndexMetaData	getIndexMetaData() Accessor for indexMetaData
VersionStrategy	getVersionStrategy() Accessor for versionStrategy
void	initialise() Initialisation method.
void	setIndexMetaData(IndexMetaData indexMetaData) Mutator for the index MetaData
java.lang.String	toString() Accessor for a string representation of the object.
java.lang.String	toString(java.lang.String prefix, java.lang.String indent) Returns a string representation of the object using a prefix This can be used as part of a facility to output a MetaData file.

Methods inherited from class org.jpox.metadata.ExtendableMetaData

addExtension, addExtension, getExtension, getExtensions, getNoOfExtensions, getValueForExtension, getValuesForExtension, getValuesForExtensionStartingWith, hasExtension, removeExtension

Methods inherited from class org.jpox.metadata.MetaData

getParent, isCreated, isInitialised, isPopulated, isUsed, populate, setInitialised, setPopulated, setUsed

Methods inherited from class java.lang.Object

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

Field Detail

columns

protected final java.util.List columns

Columns ColumnMetaData

indexMetaData

protected IndexMetaData indexMetaData

IndexMetaData.

indexed

protected IndexedValue indexed

Indexed value

columnMetaData

protected ColumnMetaData[] columnMetaData

Contains the metadata for column

Constructor Detail

VersionMetaData

public VersionMetaData(java.lang.String versionStrategy,
                       java.lang.String column,
                       java.lang.String indexed)

Constructor.

Parameters:

versionStrategy - Strategy for versioning

column - Column name

indexed - The indexed tag

Method Detail

initialise

public void initialise()

Initialisation method. This should be called AFTER using the populate method if you are going to use populate. It creates the internal convenience arrays etc needed for normal operation.

Overrides:

initialise in class MetaData

getColumnMetaData

public final ColumnMetaData[] getColumnMetaData()

Acessor for the columns

Returns:

Returns the columnMetaData.

getVersionStrategy

public final VersionStrategy getVersionStrategy()

Accessor for versionStrategy

Returns:

Returns the versionStrategy.

getIndexMetaData

public final IndexMetaData getIndexMetaData()

Accessor for indexMetaData

Returns:

Returns the indexMetaData.

addColumn

public void addColumn(ColumnMetaData colmd)

Add a new ColumnMetaData element

Parameters:

colmd - The ColumnMetaData to add

setIndexMetaData

public final void setIndexMetaData(IndexMetaData indexMetaData)

Mutator for the index MetaData

Parameters:

indexMetaData - The indexMetaData to set.

toString

public java.lang.String toString()

Accessor for a string representation of the object.

Overrides:

toString in class ExtendableMetaData

Returns:

a string representation of the object.

toString

public java.lang.String toString(java.lang.String prefix,
                                 java.lang.String indent)

Returns a string representation of the object using a prefix This can be used as part of a facility to output a MetaData file.

Overrides:

toString in class ExtendableMetaData

Parameters:

prefix - prefix string

indent - indent string

Returns:

a string representation of the object.