LockManager

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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.

Method Summary

boolean checkRead(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          checks if there is a readlock for transaction tx on object obj.

boolean checkWrite(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          checks if there is a writelock for transaction tx on object obj.

boolean readLock(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          aquires a readlock for transaction tx on object obj.

boolean releaseLock(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          releases a lock for transaction tx on object obj.

boolean upgradeLock(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          upgrades readlock for transaction tx on object obj to a writelock.

boolean writeLock(ojb.odmg.TransactionImpl tx, java.lang.Object obj)
          aquires a writelock for transaction tx on object obj.

Method Detail

readLock

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

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