org.apache.derby.impl.store.raw.xact
Class RowLocking3

java.lang.Object
  extended byorg.apache.derby.impl.store.raw.xact.NoLocking
      extended byorg.apache.derby.impl.store.raw.xact.RowLocking3
All Implemented Interfaces:
LockingPolicy
Direct Known Subclasses:
RowLockingRR

public class RowLocking3
extends NoLocking

A locking policy that implements row level locking with isolation degree 3.

See Also:
LockingPolicy

Field Summary
protected  LockFactory lf
           
private static LockingPolicy NO_LOCK
           
 
Fields inherited from interface org.apache.derby.iapi.store.raw.LockingPolicy
MODE_CONTAINER, MODE_NONE, MODE_RECORD
 
Constructor Summary
protected RowLocking3(LockFactory lf)
           
 
Method Summary
 int getMode()
          Get the mode of this policy
protected  RowLock getReadLockType()
          Get type of lock to get while reading data.
protected  RowLock getUpdateLockType()
          Get type of lock to get while requesting "update" lock.
protected  RowLock getWriteLockType()
          Get type of lock to get while writing data.
 boolean lockContainer(Transaction t, ContainerHandle container, boolean waitForLock, boolean forUpdate)
          Obtain container level intent lock.
 void lockRecordForRead(Latch latch, RecordHandle record, boolean forUpdate)
          Obtain lock on record being read while holding a latch.
 boolean lockRecordForRead(Transaction t, ContainerHandle container_handle, RecordHandle record, boolean waitForLock, boolean forUpdate)
          Obtain lock on record being read.
 void lockRecordForWrite(Latch latch, RecordHandle record)
          Obtain lock on record being written while holding a latch.
 boolean lockRecordForWrite(Transaction t, RecordHandle record, boolean lockForInsert, boolean waitForLock)
          Obtain lock on record being written.
 void unlockContainer(Transaction t, ContainerHandle container)
          Called when a container is closed.
 void unlockRecordAfterRead(Transaction t, ContainerHandle container, RecordHandle record, boolean forUpdate, boolean row_qualified)
          Called after a record has been fetched.
 boolean zeroDurationLockRecordForWrite(Transaction t, RecordHandle record, boolean lockForPreviousKey, boolean waitForLock)
          Obtain lock on record being written.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

NO_LOCK

private static final LockingPolicy NO_LOCK

lf

protected final LockFactory lf
Constructor Detail

RowLocking3

protected RowLocking3(LockFactory lf)
Method Detail

getReadLockType

protected RowLock getReadLockType()
Get type of lock to get while reading data.

This routine is provided so that class's like RowLockingRR can override just this routine to get RS2 locks vs RS3 locks, and still reuse all the other code in this class.

Returns:
The lock type of a shared lock for this locking policy.

getUpdateLockType

protected RowLock getUpdateLockType()
Get type of lock to get while requesting "update" lock.

This routine is provided so that class's like RowLockingRR can override just this routine to get RU2 locks vs RU3 locks, and still reuse all the other code in this class.

Returns:
The lock type of a shared lock for this locking policy.

getWriteLockType

protected RowLock getWriteLockType()
Get type of lock to get while writing data.

This routine is provided so that class's like RowLockingRR can override just this routine to get RX2 locks vs RX3 locks, and still reuse all the other code in this class.

Returns:
The lock type of a shared lock for this locking policy.

lockContainer

public boolean lockContainer(Transaction t,
                             ContainerHandle container,
                             boolean waitForLock,
                             boolean forUpdate)
                      throws StandardException
Obtain container level intent lock.

This implementation of row locking is 2 level, ie. table and row locking. It will interact correctly with tables opened with ContainerLocking3 locking mode.

Updater's will get table level IX locks, and X row locks.

Reader's will get table level IS locks, and S row locks.

Specified by:
lockContainer in interface LockingPolicy
Overrides:
lockContainer in class NoLocking
Parameters:
t - Transaction to associate lock with.
container - Container to lock.
waitForLock - Should lock request wait until granted?
forUpdate - Should container be locked for update, or read?
Returns:
true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock policy was set to "false," and the lock was unavailable.
Throws:
StandardException - Standard exception policy.

lockRecordForRead

public boolean lockRecordForRead(Transaction t,
                                 ContainerHandle container_handle,
                                 RecordHandle record,
                                 boolean waitForLock,
                                 boolean forUpdate)
                          throws StandardException
Obtain lock on record being read.

Assumes that a table level IS has been acquired. Will acquire a Shared or Update lock on the row, depending on the "forUpdate" parameter.

Specified by:
lockRecordForRead in interface LockingPolicy
Overrides:
lockRecordForRead in class NoLocking
Parameters:
t - The transaction to associate the lock with.
record - The record to be locked.
waitForLock - Should lock request wait until granted?
forUpdate - Whether to open for read or write access.
Returns:
true if the lock was granted, false if waitForLock was false and the lock could not be granted.
Throws:
StandardException - Standard exception policy.

lockRecordForRead

public void lockRecordForRead(Latch latch,
                              RecordHandle record,
                              boolean forUpdate)
                       throws StandardException
Obtain lock on record being read while holding a latch.

Assumes that a table level IS has been acquired. Will acquire a Shared or Update lock on the row, depending on the "forUpdate" parameter.

Specified by:
lockRecordForRead in interface LockingPolicy
Overrides:
lockRecordForRead in class NoLocking
Parameters:
latch - The latch being held.
record - The record to be locked.
forUpdate - Whether to open for read or write access.
Throws:
StandardException - Standard exception policy.

zeroDurationLockRecordForWrite

public boolean zeroDurationLockRecordForWrite(Transaction t,
                                              RecordHandle record,
                                              boolean lockForPreviousKey,
                                              boolean waitForLock)
                                       throws StandardException
Obtain lock on record being written.

Assumes that a table level IX has been acquired. Will acquire an Exclusive (X) lock on the row.

Specified by:
zeroDurationLockRecordForWrite in interface LockingPolicy
Overrides:
zeroDurationLockRecordForWrite in class NoLocking
Parameters:
t - transaction to associate the lock with.
record - The record to be locked.
waitForLock - Should lock request wait until granted?
Returns:
true if the lock was granted, false if waitForLock was false and the lock could not be granted.
Throws:
StandardException - Standard exception policy.

lockRecordForWrite

public boolean lockRecordForWrite(Transaction t,
                                  RecordHandle record,
                                  boolean lockForInsert,
                                  boolean waitForLock)
                           throws StandardException
Obtain lock on record being written.

Assumes that a table level IX has been acquired. Will acquire an Exclusive (X) lock on the row.

Specified by:
lockRecordForWrite in interface LockingPolicy
Overrides:
lockRecordForWrite in class NoLocking
Parameters:
t - The transaction to associate the lock with.
record - The record to be locked.
lockForInsert - Lock is for an insert.
waitForLock - Should lock request wait until granted?
Returns:
true if the lock was granted, false if waitForLock was false and the lock could not be granted.
Throws:
StandardException - Standard exception policy.

lockRecordForWrite

public void lockRecordForWrite(Latch latch,
                               RecordHandle record)
                        throws StandardException
Obtain lock on record being written while holding a latch.

Assumes that a table level IX has been acquired. Will acquire an Exclusive (X) lock on the row.

Specified by:
lockRecordForWrite in interface LockingPolicy
Overrides:
lockRecordForWrite in class NoLocking
Parameters:
latch - The latch being held
record - The record to be locked.
Throws:
StandardException - Standard exception policy.

getMode

public int getMode()
Description copied from interface: LockingPolicy
Get the mode of this policy

Specified by:
getMode in interface LockingPolicy
Overrides:
getMode in class NoLocking

unlockContainer

public void unlockContainer(Transaction t,
                            ContainerHandle container)
Description copied from interface: LockingPolicy
Called when a container is closed.

Specified by:
unlockContainer in interface LockingPolicy
See Also:
ContainerHandle, ContainerHandle.close()

unlockRecordAfterRead

public void unlockRecordAfterRead(Transaction t,
                                  ContainerHandle container,
                                  RecordHandle record,
                                  boolean forUpdate,
                                  boolean row_qualified)
                           throws StandardException
Description copied from interface: LockingPolicy
Called after a record has been fetched.

Specified by:
unlockRecordAfterRead in interface LockingPolicy
Throws:
StandardException - Standard Cloudscape error policy
See Also:
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