org.firebirdsql.jdbc

Class FBTpbMapper

Implemented Interfaces:
Serializable

public class FBTpbMapper
extends java.lang.Object
implements Serializable

This class is provides mapping capabilities between standard JDBC transaction isolation level and Firebird Transaction Parameters Block (TPB).
Author:
Roman Rokytskyy

Field Summary

static String
DEFAULT_MAPPING_RESOURCE
static String
TRANSACTION_NONE
Indicates that transactions are not supported.
static String
TRANSACTION_READ_COMMITTED
Dirty reads are prevented; non-repeatable reads and phantom reads can occur.
static String
TRANSACTION_READ_UNCOMMITTED
Dirty reads, non-repeatable reads and phantom reads can occur.
static String
TRANSACTION_REPEATABLE_READ
Dirty reads and non-repeatable reads are prevented; phantom reads can occur.
static String
TRANSACTION_SERIALIZABLE
Dirty reads, non-repeatable reads and phantom reads are prevented.

Constructor Summary

FBTpbMapper(GDS gds)
Create instance of this class with the default mapping of JDBC transaction isolation levels to Firebird TPB.
FBTpbMapper(GDS gds, Map stringMapping)
Create instance of this class for the specified string mapping.
FBTpbMapper(GDS gds, String mappingResource, ClassLoader cl)
Create instance of this class and load mapping from the specified resource.

Method Summary

static FBTpbMapper
getDefaultMapper(GDS gds)
TransactionParameterBuffer
getDefaultMapping()
Get default mapping.
int
getDefaultTransactionIsolation()
TransactionParameterBuffer
getMapping(int transactionIsolation)
Get mapping for the specified transaction isolation level.
static int
getTransactionIsolationLevel(String isolationName)
Convert transaction isolation level name into a corresponding constant.
static String
getTransactionIsolationName(int isolationLevel)
Convert transaction isolation level into string.
static TransactionParameterBuffer
processMapping(GDS gds, String mapping)
Process comma-separated list of keywords and convert them into TPB values.
void
setDefaultTransactionIsolation(int isolationLevel)
void
setMapping(int transactionIsolation, TransactionParameterBuffer tpb)
Set mapping for the specified transaction isolation.

Field Details

DEFAULT_MAPPING_RESOURCE

public static final String DEFAULT_MAPPING_RESOURCE

TRANSACTION_NONE

public static final String TRANSACTION_NONE
Indicates that transactions are not supported. This level is not supported

TRANSACTION_READ_COMMITTED

public static final String TRANSACTION_READ_COMMITTED
Dirty reads are prevented; non-repeatable reads and phantom reads can occur. This level only prohibits a transaction from reading a row with uncommitted changes in it.

TRANSACTION_READ_UNCOMMITTED

public static final String TRANSACTION_READ_UNCOMMITTED
Dirty reads, non-repeatable reads and phantom reads can occur. This level allows a row changed by one transaction to be read by another transaction before any changes in that row have been committed (a "dirty read"). If any of the changes are rolled back, the second transaction will have retrieved an invalid row. This level is not actually supported

TRANSACTION_REPEATABLE_READ

public static final String TRANSACTION_REPEATABLE_READ
Dirty reads and non-repeatable reads are prevented; phantom reads can occur. This level prohibits a transaction from reading a row with uncommitted changes in it, and it also prohibits the situation where one transaction reads a row, a second transaction alters the row, and the first transaction rereads the row, getting different values the second time (a "non-repeatable read").

TRANSACTION_SERIALIZABLE

public static final String TRANSACTION_SERIALIZABLE
Dirty reads, non-repeatable reads and phantom reads are prevented. This level includes the prohibitions in TRANSACTION_REPEATABLE_READ and further prohibits the situation where one transaction reads all rows that satisfy a WHERE condition, a second transaction inserts a row that satisfies that WHERE condition, and the first transaction rereads for the same condition, retrieving the additional "phantom" row in the second read.

Constructor Details

FBTpbMapper

public FBTpbMapper(GDS gds)
Create instance of this class with the default mapping of JDBC transaction isolation levels to Firebird TPB.

FBTpbMapper

public FBTpbMapper(GDS gds,
                   Map stringMapping)
            throws FBResourceException
Create instance of this class for the specified string mapping.
Parameters:
stringMapping - mapping of JDBC transaction isolation to Firebird mapping. Keys and values of this map must be strings. Keys can have following values:
  • "TRANSACTION_SERIALIZABLE"
  • "TRANSACTION_REPEATABLE_READ"
  • "TRANSACTION_READ_COMMITTED"
  • "TRANSACTION_READ_UNCOMMITTED"
Values are specified as comma-separated list of following keywords:
  • "isc_tpb_consistency"
  • "isc_tpb_concurrency"
  • "isc_tpb_read_committed"
  • "isc_tpb_rec_version"
  • "isc_tpb_no_rec_version"
  • "isc_tpb_wait"
  • "isc_tpb_nowait"
  • "isc_tpb_read"
  • "isc_tpb_write"
  • "isc_tpb_lock_read"
  • "isc_tpb_lock_write"
  • "isc_tpb_shared"
  • "isc_tpb_protected"
It is also allowed to strip "isc_tpb_" prefix from above shown constans. Meaning of these constants and possible combinations you can find in a documentation.
Throws:
FBResourceException - if mapping contains incorrect values.

FBTpbMapper

public FBTpbMapper(GDS gds,
                   String mappingResource,
                   ClassLoader cl)
            throws FBResourceException
Create instance of this class and load mapping from the specified resource.
Parameters:
mappingResource - name of the resource to load.
cl - class loader that should be used to load specified resource.
Throws:
FBResourceException - if resource cannot be loaded or contains incorrect values.

Method Details

getDefaultMapper

public static FBTpbMapper getDefaultMapper(GDS gds)

getDefaultMapping

public TransactionParameterBuffer getDefaultMapping()
Get default mapping. Default mapping represents a TPB mapping for the default transaction isolation level (read committed).
Returns:
mapping for the default transaction isolation level.

getDefaultTransactionIsolation

public int getDefaultTransactionIsolation()

getMapping

public TransactionParameterBuffer getMapping(int transactionIsolation)
Get mapping for the specified transaction isolation level.
Parameters:
transactionIsolation - transaction isolation level.
Returns:
set with TPB parameters.

getTransactionIsolationLevel

public static int getTransactionIsolationLevel(String isolationName)
Convert transaction isolation level name into a corresponding constant.
Parameters:
isolationName - name of the transaction isolation.
Returns:
corresponding constant.

getTransactionIsolationName

public static String getTransactionIsolationName(int isolationLevel)
Convert transaction isolation level into string.
Parameters:
isolationLevel - transaction isolation level as integer constant.
Returns:
corresponding string representation.

processMapping

public static TransactionParameterBuffer processMapping(GDS gds,
                                                        String mapping)
            throws FBResourceException
Process comma-separated list of keywords and convert them into TPB values.
Parameters:
mapping - comma-separated list of keywords.
Returns:
set containing values corresponding to the specified keywords.
Throws:
FBResourceException - if mapping contains keyword that is not a TPB parameter.

setDefaultTransactionIsolation

public void setDefaultTransactionIsolation(int isolationLevel)

setMapping

public void setMapping(int transactionIsolation,
                       TransactionParameterBuffer tpb)
Set mapping for the specified transaction isolation.
Parameters:
transactionIsolation - transaction isolation level.
tpb - TPB parameters.

Copyright B) 2001 David Jencks and other authors. All rights reserved.