public interface DataTreeProducer extends DataTreeProducerFactory, AutoCloseable
Each instance has an upper bound on the number of transactions which can be in-flight, once that capacity is exceeded, an attempt to create a new transaction will block until some transactions complete.
Each DataTreeProducer
can be in two logical states, bound and unbound, which define the
lifecycle rules for when is it legal to create and submit transactions in relationship with
DataTreeListener
callbacks.
When a producer is first created, it is unbound. In this state the producer can be accessed by
any application thread to allocate or submit transactions, as long as the 'single open
transaction' rule is maintained. The producer and any transaction object MUST NOT be accessed,
directly or indirectly, from a DataTreeListener
callback.
When a producer is referenced in a call to
DataTreeService.registerListener(DataTreeListener, java.util.Collection, boolean, java.util.Collection)
,
an attempt will be made to bind the producer to the specified DataTreeListener
. Such an attempt will fail
the producer is already bound, or it has an open transaction. Once bound, the producer can only be accessed
from within the DataTreeListener
callback on that particular instance. Any transaction which is not submitted
by the time the callback returns will be implicitly cancelled. A producer becomes unbound when the listener it is
bound to becomes unregistered.
Modifier and Type | Method and Description |
---|---|
void |
close()
.
|
DataTreeProducer |
createProducer(Collection<DataTreeIdentifier<?>> subtrees)
Create a producer, which is able to access to a set of trees.
|
@NonNull CursorAwareWriteTransaction |
createTransaction(boolean isolated)
Allocate a new open transaction on this producer.
|
@NonNull CursorAwareWriteTransaction createTransaction(boolean isolated)
isolated
- Indicates whether this transaction should be a barrier. A barrier transaction
is processed separately from any preceding transactions. Non-barrier transactions may
be merged and processed in a batch, such that any observers see the modifications
contained in them as if the modifications were made in a single transaction.CursorAwareWriteTransaction
IllegalStateException
- if a previous transaction was not closed.IllegalThreadStateException
- if the calling thread context does not match the
lifecycle rules enforced by the producer state (e.g. bound or unbound). This
exception is thrown on a best effort basis and programs should not rely on it for
correct operation.DataTreeProducer createProducer(Collection<DataTreeIdentifier<?>> subtrees)
When invoked on a DataTreeProducer
, this method has additional restrictions. There
may not be an open transaction from this producer. The method needs to be invoked in
appropriate context, e.g. bound or unbound.
Specified subtrees must be accessible by this producer. Accessible means they are a subset of the subtrees specified when the producer is instantiated. The set is further reduced as child producers are instantiated -- if you create a producer for /a and then a child for /a/b, /a/b is not accessible from the first producer.
Once this method returns successfully, this (parent) producer loses the ability to access the specified paths until the resulting (child) producer is shut down.
createProducer
in interface DataTreeProducerFactory
subtrees
- The collection of subtrees the resulting producer should have access to.DataTreeProducer
instance.IllegalStateException
- if there is an open transactionIllegalArgumentException
- if subtrees contains a subtree which is not accessible by
this producerIllegalThreadStateException
- if the calling thread context does not match the
lifecycle rules enforced by the producer state (e.g. bound or unbound). This
exception is thrown on a best effort basis and programs should not rely on it for
correct operation.void close() throws DataTreeProducerException
close
in interface AutoCloseable
DataTreeProducerBusyException
- when there is an open transaction.DataTreeProducerException
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