com.ibm.ism.content.psdi.tools

Class MaxSequenceProvider

java.lang.Object

com.ibm.ism.content.psdi.tools.MaxSequenceProvider

public class MaxSequenceProvider
extends java.lang.Object

Generates unique ids for columns that require unique numbers. Currently this is only used for sql server. For databases with sequence generators, database sequences are used. Uses entries from maxsequence table to find the next unique id. If an entry is not found in the maxsequence table, an entry is entered with the maximum value of the column from the table column. The maximum value of the generted key is 2147483647. If the system reaches this limit, then it tries to find from the particular table such as PRLINE to see if there are any gaps in the sequence and tries to use the ids from the found gap. This logic kicks in only when the maximum value of 2147483647 is reached during the id generation.

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.util.HashMap	hm This object stores the providers with the key being + "_" + .
protected static java.util.HashMap	hmMain This object stores the providers with the key being and the value being set of hm key (see above).
protected static java.util.HashMap	tableOrNot Hashmap to keep track of maxsequence entries which are not tables

Constructor Summary

Constructors

Constructor and Description
MaxSequenceProvider() Constructor sets up the provider to return unique IDs for the given table column.

Method Summary

Modifier and Type	Method and Description
long	getUniqueID(java.sql.Connection con, java.lang.String tbname, java.lang.String name) Returns a uniqueID for a given table and column defined in maxsequence table.
void	init(java.sql.Connection con) Calls init with second parameter True, to load all sequences.
void	init(java.sql.Connection conn, boolean loadAll) Initializes the sequences.

Methods inherited from class java.lang.Object

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

Field Detail

hm

protected static java.util.HashMap hm

This object stores the providers with the key being + "_" + . The key is uppercased.

hmMain

protected static java.util.HashMap hmMain

This object stores the providers with the key being and the value being set of hm key (see above).

tableOrNot

protected static java.util.HashMap tableOrNot

Hashmap to keep track of maxsequence entries which are not tables

Constructor Detail

MaxSequenceProvider

public MaxSequenceProvider()

Constructor sets up the provider to return unique IDs for the given table column.

Parameters:

tbname - Name of the table.

name - Name of the column.

Method Detail

init

public void init(java.sql.Connection con)
          throws java.lang.Exception

Calls init with second parameter True, to load all sequences.

Parameters:

con -

Throws:

java.lang.Exception

init

public void init(java.sql.Connection conn,
                 boolean loadAll)
          throws java.lang.Exception

Initializes the sequences. Data is read from the maxsequences table and kept in a cache.

Parameters:

con - Connection

loadAll - True will load all sequences. False will load only the sequences used by Maximo metadata tables (maxobject, maxattribute, etc.). See MaximoDD reload.

Throws:

java.lang.Exception

getUniqueID

public long getUniqueID(java.sql.Connection con,
                        java.lang.String tbname,
                        java.lang.String name)
                 throws java.lang.Exception

Returns a uniqueID for a given table and column defined in maxsequence table. The maximum ID returned in 2147483645 ( Integer.MAX_VALUE).

Parameters:

con - Database connection

tbname - Table name

name - Column name in the associated table (tbname) for which the unique number is generated.

Returns:

a guaranteed unique ID, which will be greater than 0.

Throws:

java.lang.Exception