org.apache.accumulo.fate
Class ReadOnlyStore<T>

java.lang.Object
  org.apache.accumulo.fate.ReadOnlyStore<T>

All Implemented Interfaces:

ReadOnlyTStore<T>

public class ReadOnlyStore<T>
extends Object
implements ReadOnlyTStore<T>

This store decorates a TStore to make sure it can not be modified. Unlike relying directly on the ReadOnlyTStore interface, this class will not allow subsequent users to cast back to a mutable TStore successfully.

Nested Class Summary

protected static class

ReadOnlyStore.ReadOnlyRepoWrapper<X> Decorates a Repo to make sure it is treated as a ReadOnlyRepo.

Nested classes/interfaces inherited from interface org.apache.accumulo.fate.ReadOnlyTStore

ReadOnlyTStore.TStatus

Constructor Summary

ReadOnlyStore(TStore<T> store)

Method Summary

Serializable	getProperty(long tid, String prop) Retrieve a transaction-specific property.
ReadOnlyTStore.TStatus	getStatus(long tid) Get the state of a given transaction.
List<Long>	list() list all transaction ids in store.
long	reserve() Reserve a transaction that is IN_PROGRESS or FAILED_IN_PROGRESS.
void	reserve(long tid) Reserve the specific tid.
ReadOnlyRepo<T>	top(long tid) Get the current operation for the given transaction id.
void	unreserve(long tid, long deferTime) Return the given transaction to the store.
ReadOnlyTStore.TStatus	waitForStatusChange(long tid, EnumSet<ReadOnlyTStore.TStatus> expected) Wait for the satus of a transaction to change

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadOnlyStore

public ReadOnlyStore(TStore<T> store)

Parameters:

store - may not be null

Method Detail

reserve

public long reserve()

Description copied from interface: ReadOnlyTStore

Reserve a transaction that is IN_PROGRESS or FAILED_IN_PROGRESS. Reserving a transaction id ensures that nothing else in-process interacting via the same instance will be operating on that transaction id.

Specified by:

reserve in interface ReadOnlyTStore<T>

Returns:

a transaction id that is safe to interact with, chosen by the store.

reserve

public void reserve(long tid)

Description copied from interface: ReadOnlyTStore

Reserve the specific tid. Reserving a transaction id ensures that nothing else in-process interacting via the same instance will be operating on that transaction id.

Specified by:

reserve in interface ReadOnlyTStore<T>

unreserve

public void unreserve(long tid,
                      long deferTime)

Description copied from interface: ReadOnlyTStore

Return the given transaction to the store. upon successful return the store now controls the referenced transaction id. caller should no longer interact with it.

Specified by:

unreserve in interface ReadOnlyTStore<T>

Parameters:

tid - transaction id, previously reserved.

deferTime - time in millis to keep this transaction out of the pool used in the reserve method. must be non-negative.

top

public ReadOnlyRepo<T> top(long tid)

Description copied from interface: ReadOnlyTStore

Get the current operation for the given transaction id. Caller must have already reserved tid.

Specified by:

top in interface ReadOnlyTStore<T>

Parameters:

tid - transaction id, previously reserved.

Returns:

a read-only view of the operation

getStatus

public ReadOnlyTStore.TStatus getStatus(long tid)

Description copied from interface: ReadOnlyTStore

Get the state of a given transaction. Caller must have already reserved tid.

Specified by:

getStatus in interface ReadOnlyTStore<T>

Parameters:

tid - transaction id, previously reserved.

Returns:

execution status

waitForStatusChange

public ReadOnlyTStore.TStatus waitForStatusChange(long tid,
                                                  EnumSet<ReadOnlyTStore.TStatus> expected)

Description copied from interface: ReadOnlyTStore

Wait for the satus of a transaction to change

Specified by:

waitForStatusChange in interface ReadOnlyTStore<T>

Parameters:

tid - transaction id, need not have been reserved.

expected - a set of possible statuses we are interested in being notified about. may not be null.

Returns:

execution status.

getProperty

public Serializable getProperty(long tid,
                                String prop)

Description copied from interface: ReadOnlyTStore

Retrieve a transaction-specific property. Caller must have already reserved tid.

Specified by:

getProperty in interface ReadOnlyTStore<T>

Parameters:

tid - transaction id, previously reserved.

prop - name of property to retrieve.

list

public List<Long> list()

Description copied from interface: ReadOnlyTStore

list all transaction ids in store.

Specified by:

list in interface ReadOnlyTStore<T>

Returns:

all outstanding transactions, including those reserved by others.