org.datanucleus.store.rdbms.valuegenerator

Class MaxGenerator

java.lang.Object

org.datanucleus.store.valuegenerator.AbstractGenerator<T>

org.datanucleus.store.valuegenerator.AbstractConnectedGenerator<Long>

org.datanucleus.store.rdbms.valuegenerator.MaxGenerator

All Implemented Interfaces:

org.datanucleus.store.valuegenerator.ValueGenerator<Long>

public class MaxGenerator
extends org.datanucleus.store.valuegenerator.AbstractConnectedGenerator<Long>

ValueGenerator for RDBMS that uses the "SELECT MAX(column) FROM TABLE" strategy. The allocation size is limited to 1. This works with numbers, so clients using this generator must cast the ID to Long.

Nested Class Summary

Nested classes/interfaces inherited from class org.datanucleus.store.valuegenerator.AbstractConnectedGenerator

org.datanucleus.store.valuegenerator.AbstractConnectedGenerator.ConnectionPreference

Field Summary

Fields inherited from class org.datanucleus.store.valuegenerator.AbstractConnectedGenerator

connectionProvider, properties

Fields inherited from class org.datanucleus.store.valuegenerator.AbstractGenerator

allocationSize, block, initialValue, name, storeMgr

Fields inherited from interface org.datanucleus.store.valuegenerator.ValueGenerator

PROPERTY_CATALOG_NAME, PROPERTY_CLASS_NAME, PROPERTY_COLUMN_NAME, PROPERTY_FIELD_NAME, PROPERTY_KEY_CACHE_SIZE, PROPERTY_KEY_DATABASE_CACHE_SIZE, PROPERTY_KEY_INITIAL_VALUE, PROPERTY_KEY_MAX_VALUE, PROPERTY_KEY_MIN_VALUE, PROPERTY_ROOT_CLASS_NAME, PROPERTY_SCHEMA_NAME, PROPERTY_SEQUENCE_NAME, PROPERTY_SEQUENCETABLE_CATALOG, PROPERTY_SEQUENCETABLE_NAME_COLUMN, PROPERTY_SEQUENCETABLE_NEXTVAL_COLUMN, PROPERTY_SEQUENCETABLE_SCHEMA, PROPERTY_SEQUENCETABLE_TABLE, PROPERTY_TABLE_NAME

Constructor Summary

Constructors

Constructor and Description
MaxGenerator(org.datanucleus.store.StoreManager storeMgr, String name, Properties props) Constructor.

Method Summary

Modifier and Type	Method and Description
org.datanucleus.store.valuegenerator.AbstractConnectedGenerator.ConnectionPreference	getConnectionPreference()
org.datanucleus.store.valuegenerator.ValueGenerationBlock	reserveBlock(long size) Method to reserve a block of identities.

Methods inherited from class org.datanucleus.store.valuegenerator.AbstractConnectedGenerator

setConnectionProvider

Methods inherited from class org.datanucleus.store.valuegenerator.AbstractGenerator

allocate, current, currentValue, getName, next, nextValue, obtainGenerationBlock, obtainGenerationBlock, reserveBlock

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxGenerator

public MaxGenerator(org.datanucleus.store.StoreManager storeMgr,
                    String name,
                    Properties props)

Constructor.

Parameters:

storeMgr - StoreManager

name - Symbolic name for this generator

props - Properties defining the behaviour of this generator

Method Detail

reserveBlock

public org.datanucleus.store.valuegenerator.ValueGenerationBlock reserveBlock(long size)

Method to reserve a block of identities. Note : Only allocates a single id always.

Specified by:

reserveBlock in class org.datanucleus.store.valuegenerator.AbstractGenerator<Long>

Parameters:

size - The block size

Returns:

The reserved block

getConnectionPreference

public org.datanucleus.store.valuegenerator.AbstractConnectedGenerator.ConnectionPreference getConnectionPreference()

Overrides:

getConnectionPreference in class org.datanucleus.store.valuegenerator.AbstractConnectedGenerator<Long>