2 * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.dom.api;
10 import java.util.Collection;
11 import javax.annotation.Nonnull;
14 * A data producer context. It allows transactions to be submitted to the subtrees
15 * specified at instantiation time. At any given time there may be a single transaction
16 * open. It needs to be either submitted or cancelled before another one can be open.
17 * Once a transaction is submitted, it will proceed to be committed asynchronously.
19 * Each instance has an upper bound on the number of transactions which can be in-flight,
20 * once that capacity is exceeded, an attempt to create a new transaction will block
21 * until some transactions complete.
23 * Each {@link DOMDataTreeProducer} can be in two logical states, bound and unbound,
24 * which define the lifecycle rules for when is it legal to create and submit transactions
25 * in relationship with {@link DOMDataTreeListener} callbacks.
27 * When a producer is first created, it is unbound. In this state the producer can be
28 * accessed by any application thread to allocate or submit transactions, as long as
29 * the 'single open transaction' rule is maintained. The producer and any transaction
30 * object MUST NOT be accessed, directly or indirectly, from a {@link DOMDataTreeListener}
33 * When a producer is referenced in a call to {@link DOMDataTreeService#registerListener(DOMDataTreeListener, java.util.Collection, boolean, java.util.Collection)},
34 * an attempt will be made to bind the producer to the specified {@link DOMDataTreeListener}.
35 * Such an attempt will fail the producer is already bound, or it has an open transaction.
36 * Once bound, the producer can only be accessed from within the {@link DOMDataTreeListener}
37 * callback on that particular instance. Any transaction which is not submitted by the
38 * time the callback returns will be implicitly cancelled. A producer becomes unbound
39 * when the listener it is bound to becomes unregistered.
41 public interface DOMDataTreeProducer extends DOMDataTreeProducerFactory, AutoCloseable {
43 * Allocate a new open transaction on this producer. Any and all transactions previously
44 * allocated must have been either submitted or cancelled by the time this method is invoked.
46 * @param isolated Indicates whether this transaction should be a barrier. A barrier transaction
47 * is processed separately from any preceding transactions. Non-barrier transactions may
48 * be merged and processed in a batch, such that any observers see the modifications
49 * contained in them as if the modifications were made in a single transaction.
50 * @return A new {@link DOMDataTreeWriteTransaction}
51 * @throws IllegalStateException if a previous transaction was not closed.
52 * @throws IllegalThreadStateException if the calling thread context does not match the
53 * lifecycle rules enforced by the producer state (e.g. bound or unbound). This
54 * exception is thrown on a best effort basis and programs should not rely on it for
57 @Nonnull DOMDataTreeWriteTransaction createTransaction(boolean isolated);
62 * When invoked on a {@link DOMDataTreeProducer}, this method has additional restrictions. There
63 * may not be an open transaction from this producer. The method needs to be invoked in
64 * appropriate context, e.g. bound or unbound.
66 * Specified subtrees must be accessible by this producer. Accessible means they are a subset of
67 * the subtrees specified when the producer is instantiated. The set is further reduced as child
68 * producers are instantiated -- if you create a producer for /a and then a child for /a/b, /a/b
69 * is not accessible from the first producer.
71 * Once this method returns successfully, this (parent) producer loses the ability to access the
72 * specified paths until the resulting (child) producer is shut down.
74 * @throws IllegalStateException if there is an open transaction
75 * @throws IllegalArgumentException if subtrees contains a subtree which is not accessible by
77 * @throws IllegalThreadStateException if the calling thread context does not match the
78 * lifecycle rules enforced by the producer state (e.g. bound or unbound). This
79 * exception is thrown on a best effort basis and programs should not rely on it for
83 @Nonnull DOMDataTreeProducer createProducer(@Nonnull Collection<DOMDataTreeIdentifier> subtrees);
88 * @throws DOMDataTreeProducerBusyException when there is an open transaction.
91 void close() throws DOMDataTreeProducerException;