ojb.odmg.locking
Interface LockManager

All Known Implementing Classes:

LockManagerDefaultImpl

public interface LockManager

This interface declares the functionality of the OJB internal Locking mechanism. A default implementaion LockManagerDefaultImpl is provided. This implementaion keeps distributed locks in the database. The locking mechanisms thus involves a lot of database lookups and writes. For some environments this solution may not be adequate. OJB allows to provide user defined implementations of this interface. To activate a user defined LockManagerDefaultImpl it must be configured in the OJB.properties file.

Author:

thma

Method Summary

boolean	checkRead(TransactionImpl tx, java.lang.Object obj) checks if there is a readlock for transaction tx on object obj.
boolean	checkWrite(TransactionImpl tx, java.lang.Object obj) checks if there is a writelock for transaction tx on object obj.
boolean	readLock(TransactionImpl tx, java.lang.Object obj) aquires a readlock for transaction tx on object obj.
boolean	releaseLock(TransactionImpl tx, java.lang.Object obj) releases a lock for transaction tx on object obj.
boolean	upgradeLock(TransactionImpl tx, java.lang.Object obj) upgrades readlock for transaction tx on object obj to a writelock.
boolean	writeLock(TransactionImpl tx, java.lang.Object obj) aquires a writelock for transaction tx on object obj.

Method Detail

readLock

public boolean readLock(TransactionImpl tx,
                        java.lang.Object obj)

aquires a readlock for transaction tx on object obj. Returns true if successful, else false.

writeLock

public boolean writeLock(TransactionImpl tx,
                         java.lang.Object obj)

aquires a writelock for transaction tx on object obj. Returns true if successful, else false.

upgradeLock

public boolean upgradeLock(TransactionImpl tx,
                           java.lang.Object obj)

upgrades readlock for transaction tx on object obj to a writelock. If no readlock existed a writelock is acquired anyway. Returns true if successful, else false.

releaseLock

public boolean releaseLock(TransactionImpl tx,
                           java.lang.Object obj)

releases a lock for transaction tx on object obj. Returns true if successful, else false.

checkRead

public boolean checkRead(TransactionImpl tx,
                         java.lang.Object obj)

checks if there is a readlock for transaction tx on object obj. Returns true if so, else false.

checkWrite

public boolean checkWrite(TransactionImpl tx,
                          java.lang.Object obj)

checks if there is a writelock for transaction tx on object obj. Returns true if so, else false.