+/*
+ * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.dom.api;
+
+import java.util.Collection;
+import javax.annotation.Nonnull;
+
+/**
+ * A data producer context. It allows transactions to be submitted to the subtrees
+ * specified at instantiation time. At any given time there may be a single transaction
+ * open. It needs to be either submitted or cancelled before another one can be open.
+ * Once a transaction is submitted, it will proceed to be committed asynchronously.
+ *
+ * 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 {@link DOMDataTreeProducer} 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 {@link DOMDataTreeListener} 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 {@link DOMDataTreeListener}
+ * callback.
+ *
+ * When a producer is referenced in a call to {@link DOMDataTreeService#registerListener(DOMDataTreeListener, java.util.Collection, boolean, java.util.Collection)},
+ * an attempt will be made to bind the producer to the specified {@link DOMDataTreeListener}.
+ * 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 {@link DOMDataTreeListener}
+ * 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.
+ */
+public interface DOMDataTreeProducer extends DOMDataTreeProducerFactory, AutoCloseable {
+ /**
+ * Allocate a new open transaction on this producer. Any and all transactions
+ * previously allocated must have been either submitted or cancelled by the
+ * time this method is invoked.
+ *
+ * @param barrier 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.
+ * @return A new {@link DOMDataWriteTransaction}
+ * @throws {@link IllegalStateException} if a previous transaction was not closed.
+ * @throws {@link 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.
+ */
+ @Nonnull DOMDataWriteTransaction createTransaction(boolean isolated);
+
+ /**
+ * {@inheritDoc}
+ *
+ * When invoked on a {@link DOMDataTreeProducer}, 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.
+ *
+ * @throws {@link IllegalStateException} if there is an open transaction
+ * @throws {@link IllegalArgumentException} if subtrees contains a subtree which is not
+ * accessible by this producer
+ * @throws {@link 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.
+ */
+ @Override
+ @Nonnull DOMDataTreeProducer createProducer(@Nonnull Collection<DOMDataTreeIdentifier> subtrees);
+
+ /**
+ * {@inheritDoc}
+ *
+ * @throws DOMDataTreeProducerBusyException when there is an open transaction.
+ */
+ @Override
+ void close() throws DOMDataTreeProducerException;
+}
Code Review / controller.git / commitdiff