com.netflix.astyanax.recipes.locks

Class OneStepDistributedRowLock<K,C>

java.lang.Object

com.netflix.astyanax.recipes.locks.OneStepDistributedRowLock<K,C>

All Implemented Interfaces:

DistributedRowLock

public class OneStepDistributedRowLock<K,C>
extends java.lang.Object
implements DistributedRowLock

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.concurrent.TimeUnit	DEFAULT_OPERATION_TIMEOUT_UNITS
static int	LOCK_TIMEOUT

Constructor Summary

Constructors

Constructor and Description
OneStepDistributedRowLock(com.netflix.astyanax.Keyspace keyspace, com.netflix.astyanax.model.ColumnFamily<K,C> columnFamily, K key)

Method Summary

Modifier and Type	Method and Description
void	acquire() Try to take the lock.
com.netflix.astyanax.model.ColumnMap<C>	acquireLockAndReadRow() Take the lock and return the row data columns.
OneStepDistributedRowLock<K,C>	expireLockAfter(long timeout, java.util.concurrent.TimeUnit unit) Time for failed locks.
OneStepDistributedRowLock<K,C>	failOnStaleLock(boolean failOnStaleLock) When set to true the operation will fail if a stale lock is detected
C	fillLockMutation(com.netflix.astyanax.MutationBatch m, java.lang.Long time, java.lang.Integer ttl) Fill a mutation with the lock column.
void	fillReleaseMutation(com.netflix.astyanax.MutationBatch m, boolean excludeCurrentLock) Fill a mutation that will release the locks.
com.netflix.astyanax.model.ConsistencyLevel	getConsistencyLevel()
com.netflix.astyanax.model.ColumnMap<C>	getDataColumns()
K	getKey()
com.netflix.astyanax.Keyspace	getKeyspace()
C	getLockColumn()
int	getRetryCount()
java.util.Map<C,java.lang.Long>	readLockColumns() Return a mapping of existing lock columns and their expiration times
long	readTimeoutValue(com.netflix.astyanax.model.Column<?> column) Read the expiration time from the column value
void	release() Release the lock by releasing this and any other stale lock columns
java.util.Map<C,java.lang.Long>	releaseAllLocks() Release all locks.
java.util.Map<C,java.lang.Long>	releaseExpiredLocks() Release all expired locks for this key.
java.util.Map<C,java.lang.Long>	releaseLocks(boolean force) Delete locks columns.
void	releaseWithMutation(com.netflix.astyanax.MutationBatch m) Release using the provided mutation.
boolean	releaseWithMutation(com.netflix.astyanax.MutationBatch m, boolean force)
void	verifyLock(long curTimeInMicros) Verify that the lock was acquired.
OneStepDistributedRowLock<K,C>	withBackoff(com.netflix.astyanax.retry.RetryPolicy policy)
OneStepDistributedRowLock<K,C>	withColumnStrategy(LockColumnStrategy<C> columnStrategy)
OneStepDistributedRowLock<K,C>	withConsistencyLevel(com.netflix.astyanax.model.ConsistencyLevel consistencyLevel) Modify the consistency level being used.
OneStepDistributedRowLock<K,C>	withDataColumns(boolean flag) If true the first read will also fetch all the columns in the row as opposed to just the lock columns.
OneStepDistributedRowLock<K,C>	withTtl(java.lang.Integer ttl) This is the TTL on the lock column being written, as opposed to expireLockAfter which is written as the lock column value.
OneStepDistributedRowLock<K,C>	withTtl(java.lang.Integer ttl, java.util.concurrent.TimeUnit units)

Methods inherited from class java.lang.Object

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

Field Detail

LOCK_TIMEOUT

public static final int LOCK_TIMEOUT

See Also:

Constant Field Values

DEFAULT_OPERATION_TIMEOUT_UNITS

public static final java.util.concurrent.TimeUnit DEFAULT_OPERATION_TIMEOUT_UNITS

Constructor Detail

OneStepDistributedRowLock

public OneStepDistributedRowLock(com.netflix.astyanax.Keyspace keyspace,
                                 com.netflix.astyanax.model.ColumnFamily<K,C> columnFamily,
                                 K key)

Method Detail

withColumnStrategy

public OneStepDistributedRowLock<K,C> withColumnStrategy(LockColumnStrategy<C> columnStrategy)

withConsistencyLevel

public OneStepDistributedRowLock<K,C> withConsistencyLevel(com.netflix.astyanax.model.ConsistencyLevel consistencyLevel)

Modify the consistency level being used. Consistency should always be a variant of quorum. The default is CL_QUORUM, which is OK for single region. For multi region the consistency level should be CL_LOCAL_QUORUM. CL_EACH_QUORUM can be used but will Incur substantial latency.

Parameters:

consistencyLevel -

Returns:

withDataColumns

public OneStepDistributedRowLock<K,C> withDataColumns(boolean flag)

If true the first read will also fetch all the columns in the row as opposed to just the lock columns.

Parameters:

flag -

Returns:

failOnStaleLock

public OneStepDistributedRowLock<K,C> failOnStaleLock(boolean failOnStaleLock)

When set to true the operation will fail if a stale lock is detected

Parameters:

failOnStaleLock -

Returns:

expireLockAfter

public OneStepDistributedRowLock<K,C> expireLockAfter(long timeout,
                                                      java.util.concurrent.TimeUnit unit)

Time for failed locks. Under normal circumstances the lock column will be deleted. If not then this lock column will remain and the row will remain locked. The lock will expire after this timeout.

Parameters:

timeout -

unit -

Returns:

withTtl

public OneStepDistributedRowLock<K,C> withTtl(java.lang.Integer ttl)

This is the TTL on the lock column being written, as opposed to expireLockAfter which is written as the lock column value. Whereas the expireLockAfter can be used to identify a stale or abandoned lock the TTL will result in the stale or abandoned lock being eventually deleted by cassandra. Set the TTL to a number that is much greater tan the expireLockAfter time.

Parameters:

ttl -

Returns:

withTtl

public OneStepDistributedRowLock<K,C> withTtl(java.lang.Integer ttl,
                                              java.util.concurrent.TimeUnit units)

withBackoff

public OneStepDistributedRowLock<K,C> withBackoff(com.netflix.astyanax.retry.RetryPolicy policy)

acquire

public void acquire()
             throws java.lang.Exception

Try to take the lock. The caller must call .release() to properly clean up the lock columns from cassandra

Specified by:

acquire in interface DistributedRowLock

Throws:

java.lang.Exception

acquireLockAndReadRow

public com.netflix.astyanax.model.ColumnMap<C> acquireLockAndReadRow()
                                                              throws java.lang.Exception

Take the lock and return the row data columns. Use this, instead of acquire, when you want to implement a read-modify-write scenario and want to reduce the number of calls to Cassandra.

Returns:

Throws:

java.lang.Exception

verifyLock

public void verifyLock(long curTimeInMicros)
                throws java.lang.Exception,
                       BusyLockException,
                       StaleLockException

Verify that the lock was acquired. This shouldn't be called unless it's part of a recipe built on top of AbstractDistributedRowLock.

Parameters:

curTimeInMicros -

Throws:

BusyLockException

java.lang.Exception

StaleLockException

release

public void release()
             throws java.lang.Exception

Release the lock by releasing this and any other stale lock columns

Specified by:

release in interface DistributedRowLock

Throws:

java.lang.Exception

releaseWithMutation

public void releaseWithMutation(com.netflix.astyanax.MutationBatch m)
                         throws java.lang.Exception

Release using the provided mutation. Use this when you want to commit actual data when releasing the lock

Parameters:

m -

Throws:

java.lang.Exception

releaseWithMutation

public boolean releaseWithMutation(com.netflix.astyanax.MutationBatch m,
                                   boolean force)
                            throws java.lang.Exception

Throws:

java.lang.Exception

readLockColumns

public java.util.Map<C,java.lang.Long> readLockColumns()
                                                throws java.lang.Exception

Return a mapping of existing lock columns and their expiration times

Returns:

Throws:

java.lang.Exception

releaseAllLocks

public java.util.Map<C,java.lang.Long> releaseAllLocks()
                                                throws java.lang.Exception

Release all locks. Use this carefully as it could release a lock for a running operation.

Returns:

Throws:

java.lang.Exception

releaseExpiredLocks

public java.util.Map<C,java.lang.Long> releaseExpiredLocks()
                                                    throws java.lang.Exception

Release all expired locks for this key.

Returns:

Throws:

java.lang.Exception

releaseLocks

public java.util.Map<C,java.lang.Long> releaseLocks(boolean force)
                                             throws java.lang.Exception

Delete locks columns. Set force=true to remove locks that haven't expired yet. This operation first issues a read to cassandra and then deletes columns in the response.

Parameters:

force - - Force delete of non expired locks as well

Returns:

Throws:

java.lang.Exception

fillLockMutation

public C fillLockMutation(com.netflix.astyanax.MutationBatch m,
                          java.lang.Long time,
                          java.lang.Integer ttl)

Fill a mutation with the lock column. This may be used when the mutation is executed externally but should be used with extreme caution to ensure the lock is properly released

Parameters:

m -

time -

ttl -

readTimeoutValue

public long readTimeoutValue(com.netflix.astyanax.model.Column<?> column)

Read the expiration time from the column value

Parameters:

column -

Returns:

fillReleaseMutation

public void fillReleaseMutation(com.netflix.astyanax.MutationBatch m,
                                boolean excludeCurrentLock)

Fill a mutation that will release the locks. This may be used from a separate recipe to release multiple locks.

Parameters:

m -

getDataColumns

public com.netflix.astyanax.model.ColumnMap<C> getDataColumns()

getKey

public K getKey()

getKeyspace

public com.netflix.astyanax.Keyspace getKeyspace()

getConsistencyLevel

public com.netflix.astyanax.model.ConsistencyLevel getConsistencyLevel()

getLockColumn

public C getLockColumn()

getRetryCount

public int getRetryCount()