public abstract class BasicTransactionSemantics extends Object implements Transaction
An implementation of basic Transaction
semantics designed
to work in concert with BasicChannelSemantics
to simplify
creation of robust Channel
implementations. This class
ensures that each transaction implementation method is called only
while the transaction is in the correct state for that method, and
only by the thread that created the transaction. Nested calls to
begin()
and close()
are supported as long
as they are balanced.
Subclasses need only implement doPut
,
doTake
, doCommit
, and
doRollback
, and the developer can rest assured that
those methods are called only after transaction state preconditions
have been properly met. doBegin
and
doClose
may also be implemented if there is work to be
done at those points.
All InterruptedException exceptions thrown from the implementations
of the doXXX
methods are automatically wrapped to
become ChannelExceptions, but only after restoring the interrupted
status of the thread so that any subsequent blocking method calls
will themselves throw InterruptedException rather than blocking.
The exception to this rule is doTake
, which simply
returns null instead of wrapping and propagating the
InterruptedException, though it still first restores the
interrupted status of the thread.
Modifier and Type | Class and Description |
---|---|
protected static class |
BasicTransactionSemantics.State
The state of the
Transaction to which it belongs. |
Transaction.TransactionState
Modifier | Constructor and Description |
---|---|
protected |
BasicTransactionSemantics() |
Modifier and Type | Method and Description |
---|---|
void |
begin()
Starts a transaction boundary for the current channel operation.
|
void |
close()
Ends a transaction boundary for the current channel operation.
|
void |
commit()
Indicates that the transaction can be successfully committed.
|
protected void |
doBegin() |
protected void |
doClose() |
protected abstract void |
doCommit() |
protected abstract void |
doPut(Event event) |
protected abstract void |
doRollback() |
protected abstract Event |
doTake() |
protected BasicTransactionSemantics.State |
getState() |
protected void |
put(Event event)
The method to which
BasicChannelSemantics delegates calls
to put . |
void |
rollback()
Indicates that the transaction can must be aborted.
|
protected Event |
take()
The method to which
BasicChannelSemantics delegates calls
to take . |
String |
toString() |
protected void doBegin() throws InterruptedException
InterruptedException
protected abstract void doPut(Event event) throws InterruptedException
InterruptedException
protected abstract Event doTake() throws InterruptedException
InterruptedException
protected abstract void doCommit() throws InterruptedException
InterruptedException
protected abstract void doRollback() throws InterruptedException
InterruptedException
protected void doClose()
protected void put(Event event)
The method to which BasicChannelSemantics
delegates calls
to put
.
protected Event take()
The method to which BasicChannelSemantics
delegates calls
to take
.
protected BasicTransactionSemantics.State getState()
public void begin()
Transaction
Starts a transaction boundary for the current channel operation. If a transaction is already in progress, this method will join that transaction using reference counting.
Note: For every invocation of this method there must be a corresponding invocation of Transaction.close() method. Failure to ensure this can lead to dangling transactions and unpredictable results.
begin
in interface Transaction
public void commit()
Transaction
commit
in interface Transaction
public void rollback()
Transaction
rollback
in interface Transaction
public void close()
Transaction
Ends a transaction boundary for the current channel operation. If a transaction is already in progress, this method will join that transaction using reference counting. The transaction is completed only if there are no more references left for this transaction.
Note: For every invocation of this method there must be a corresponding invocation of Transaction.begin() method. Failure to ensure this can lead to dangling transactions and unpredictable results.
close
in interface Transaction
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