psdi.util

Class MaxSequenceProvider

java.lang.Object

psdi.util.MaxSequenceProvider

All Implemented Interfaces:

FixedLoggerNames, FixedLoggers

public class MaxSequenceProvider
extends java.lang.Object
implements FixedLoggers

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. First Mode
The maximum value of the generated key is Long.MAXVALUE. Before this limit, a range of values is reserved by updating the MaxReserved value in MaxSequence. The values lower that MaxReserved are assumed to be used or will be used by another unique ID provider. Second Mode
If the system reaches this limit, then it looks at the tables that use the sequence 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. In the MaxSequence table, MaxValue acts like MaxReserved did, but with Range set as the maximum free value found in the gap.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	MaxSequenceProvider.EmptyLogger This logger is used when the provider isn't running as part of MXServer

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.HashMap	maxSeqLookup This object stores the providers with the key being the sequence name, uppercased.
protected java.util.HashMap	seqTargetLookup This object stores the sequence name per table + column

Fields inherited from interface psdi.util.logging.FixedLoggers

APPLOGGER, CRONTASKLOGGER, CRONTASKMGRLOGGER, CRONTASKMGRSQLLOGGER, DBCONNECTIONLOGGER, DDLOGGER, DMLOGGER, EVENTLOGGER, EXCEPTIONLOGGER, MAILLOGGER, MAXIMOLOGGER, MTLOGGER, NULLMBOPOINTER, SECURITY, SENDFAILEDLOGGER, SERVICELOGGER, SQLLOGGER

Fields inherited from interface psdi.util.logging.FixedLoggerNames

appenderPrefix, LOGGERNAME_APP, LOGGERNAME_CRONTASK, LOGGERNAME_CRONTASKMGR, LOGGERNAME_DBCONNECTION, LOGGERNAME_DD, LOGGERNAME_DM, LOGGERNAME_DMPREVIEW, LOGGERNAME_EVENT, LOGGERNAME_EXCEPTION, LOGGERNAME_MAIL, LOGGERNAME_MAXIMO, LOGGERNAME_MT, LOGGERNAME_NULLMBOPOINTER, LOGGERNAME_SECURITY, LOGGERNAME_SENDFAILED, LOGGERNAME_SERVICE, LOGGERNAME_SQL, LOGGERNAME_SQL_CRONTASKMGR, LOGGERNAME_TXN, loggerPrefix

Constructor Summary

Constructors

Constructor and Description
MaxSequenceProvider()
MaxSequenceProvider(MXLogger methodLogger, MXLogger sqlLogger)

Method Summary

Modifier and Type	Method and Description
boolean	exists(java.sql.Connection con, java.lang.String query) Helper method returns true if the query returns a row.
java.lang.Long	getUniqueID(java.sql.Connection con, java.lang.String seqName) Return the next value for the sequence.
long	getUniqueID(java.sql.Connection conn, 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.
java.lang.Long	reserveMultiple(java.sql.Connection con, java.lang.String seqName, int numToReserve)
static void	resetProviders()
void	resetSequence(java.sql.Connection connection, java.lang.String sequence) It has been found that this sequence has invalid values for it in MaxSequence.

Methods inherited from class java.lang.Object

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

Field Detail

maxSeqLookup

protected java.util.HashMap maxSeqLookup

This object stores the providers with the key being the sequence name, uppercased.

seqTargetLookup

protected java.util.HashMap seqTargetLookup

This object stores the sequence name per table + column

Constructor Detail

MaxSequenceProvider

public MaxSequenceProvider()

MaxSequenceProvider

public MaxSequenceProvider(MXLogger methodLogger,
                           MXLogger sqlLogger)

Method Detail

resetProviders

public static void resetProviders()

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.sql.SQLException

Initializes the sequences. Data is read from the maxsequences table and kept in a cache. Note: calling this method a second time won't do anything. This is because another unique ID provider could have reserved values so we can't reload anything.

Parameters:

con - Connection

loadAll - True will load all sequences. False, and this method does nothing.

Throws:

java.sql.SQLException

exists

public boolean exists(java.sql.Connection con,
                      java.lang.String query)
               throws java.sql.SQLException

Helper method returns true if the query returns a row.

Throws:

java.sql.SQLException

getUniqueID

public java.lang.Long getUniqueID(java.sql.Connection con,
                                  java.lang.String seqName)
                           throws java.sql.SQLException

Return the next value for the sequence.

Throws:

java.sql.SQLException

getUniqueID

public long getUniqueID(java.sql.Connection conn,
                        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 is MAXVALUE.

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

See Also:

Maximum possible value returned.

resetSequence

public void resetSequence(java.sql.Connection connection,
                          java.lang.String sequence)
                   throws java.sql.SQLException

It has been found that this sequence has invalid values for it in MaxSequence. This method reset the values in MaxSequence so they are correct.

Parameters:

connection - Connection to the database

sequence - The sequence to reset

Throws:

java.lang.Exception

java.sql.SQLException

reserveMultiple

public java.lang.Long reserveMultiple(java.sql.Connection con,
                                      java.lang.String seqName,
                                      int numToReserve)
                               throws java.sql.SQLException

Throws:

java.sql.SQLException