Java tutorial
/* * Copyright (c) 2017 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.cluster.sharding; import com.google.common.util.concurrent.AsyncFunction; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.MoreExecutors; import java.util.Collection; import java.util.concurrent.ExecutionException; import org.opendaylight.controller.cluster.access.concepts.MemberName; import org.opendaylight.controller.cluster.databroker.actors.dds.ClientLocalHistory; import org.opendaylight.controller.cluster.databroker.actors.dds.ClientSnapshot; import org.opendaylight.controller.cluster.databroker.actors.dds.ClientTransaction; import org.opendaylight.controller.cluster.databroker.actors.dds.DataStoreClient; import org.opendaylight.controller.cluster.datastore.utils.ClusterUtils; import org.opendaylight.mdsal.common.api.ReadFailedException; import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteCursor; import org.opendaylight.mdsal.dom.spi.store.DOMStoreThreePhaseCommitCohort; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifierWithPredicates; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeWithValue; import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode; import org.opendaylight.yangtools.yang.data.api.schema.LeafSetEntryNode; import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode; import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.ListNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableContainerNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableLeafNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableLeafSetEntryNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableLeafSetNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableMapEntryNodeBuilder; import org.opendaylight.yangtools.yang.data.impl.schema.builder.impl.ImmutableMapNodeBuilder; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Writes and removes prefix-based shards' configuration * to prefix-shard-configuration. This classed is meant to be utilized * by {@link DistributedShardedDOMDataTree} for updating * prefix-shard-configuration upon creating and de-spawning prefix-based shards. */ class PrefixedShardConfigWriter { private static final Logger LOG = LoggerFactory.getLogger(PrefixedShardConfigWriter.class); private final ClientLocalHistory history; PrefixedShardConfigWriter(final DataStoreClient client) { history = client.createLocalHistory(); writeInitialParent(); } ListenableFuture<Void> writeConfig(final YangInstanceIdentifier path, final Collection<MemberName> replicas) { LOG.debug("Writing config for {}, replicas {}", path, replicas); return doSubmit(doWrite(path, replicas)); } ListenableFuture<Void> removeConfig(final YangInstanceIdentifier path) { LOG.debug("Removing config for {}.", path); return doSubmit(doDelete(path)); } private void writeInitialParent() { final ClientTransaction tx = history.createTransaction(); final DOMDataTreeWriteCursor cursor = tx.openCursor(); final ContainerNode root = ImmutableContainerNodeBuilder.create() .withNodeIdentifier(new NodeIdentifier(ClusterUtils.PREFIX_SHARDS_QNAME)) .withChild(ImmutableMapNodeBuilder.create() .withNodeIdentifier(new NodeIdentifier(ClusterUtils.SHARD_LIST_QNAME)).build()) .build(); cursor.merge(ClusterUtils.PREFIX_SHARDS_PATH.getLastPathArgument(), root); cursor.close(); final DOMStoreThreePhaseCommitCohort cohort = tx.ready(); submitBlocking(cohort); } private static void submitBlocking(final DOMStoreThreePhaseCommitCohort cohort) { try { doSubmit(cohort).get(); } catch (final InterruptedException | ExecutionException e) { LOG.error("Unable to write initial shard config parent.", e); } } private static ListenableFuture<Void> doSubmit(final DOMStoreThreePhaseCommitCohort cohort) { final AsyncFunction<Boolean, Void> validateFunction = input -> cohort.preCommit(); final AsyncFunction<Void, Void> prepareFunction = input -> cohort.commit(); final ListenableFuture<Void> prepareFuture = Futures.transformAsync(cohort.canCommit(), validateFunction, MoreExecutors.directExecutor()); return Futures.transformAsync(prepareFuture, prepareFunction, MoreExecutors.directExecutor()); } boolean checkDefaultIsPresent() { final NodeIdentifierWithPredicates pag = new NodeIdentifierWithPredicates(ClusterUtils.SHARD_LIST_QNAME, ClusterUtils.SHARD_PREFIX_QNAME, YangInstanceIdentifier.EMPTY); final YangInstanceIdentifier defaultId = ClusterUtils.SHARD_LIST_PATH.node(pag); final ClientSnapshot snapshot = history.takeSnapshot(); try { return snapshot.exists(defaultId).checkedGet(); } catch (final ReadFailedException e) { LOG.error("Presence check of default shard in configuration failed.", e); return false; } finally { snapshot.abort(); } } private DOMStoreThreePhaseCommitCohort doWrite(final YangInstanceIdentifier path, final Collection<MemberName> replicas) { final ListNodeBuilder<Object, LeafSetEntryNode<Object>> replicaListBuilder = ImmutableLeafSetNodeBuilder .create().withNodeIdentifier(new NodeIdentifier(ClusterUtils.SHARD_REPLICA_QNAME)); replicas.forEach(name -> replicaListBuilder.withChild(ImmutableLeafSetEntryNodeBuilder.create() .withNodeIdentifier(new NodeWithValue<>(ClusterUtils.SHARD_REPLICA_QNAME, name.getName())) .withValue(name.getName()).build())); final MapEntryNode newEntry = ImmutableMapEntryNodeBuilder.create() .withNodeIdentifier(new NodeIdentifierWithPredicates(ClusterUtils.SHARD_LIST_QNAME, ClusterUtils.SHARD_PREFIX_QNAME, path)) .withChild(ImmutableLeafNodeBuilder.create() .withNodeIdentifier(new NodeIdentifier(ClusterUtils.SHARD_PREFIX_QNAME)).withValue(path) .build()) .withChild(ImmutableContainerNodeBuilder.create() .withNodeIdentifier(new NodeIdentifier(ClusterUtils.SHARD_REPLICAS_QNAME)) .withChild(replicaListBuilder.build()).build()) .build(); final ClientTransaction tx = history.createTransaction(); final DOMDataTreeWriteCursor cursor = tx.openCursor(); ClusterUtils.SHARD_LIST_PATH.getPathArguments().forEach(cursor::enter); cursor.write(newEntry.getIdentifier(), newEntry); cursor.close(); return tx.ready(); } private DOMStoreThreePhaseCommitCohort doDelete(final YangInstanceIdentifier path) { final ClientTransaction tx = history.createTransaction(); final DOMDataTreeWriteCursor cursor = tx.openCursor(); ClusterUtils.SHARD_LIST_PATH.getPathArguments().forEach(cursor::enter); cursor.delete(new NodeIdentifierWithPredicates(ClusterUtils.SHARD_LIST_QNAME, ClusterUtils.SHARD_PREFIX_QNAME, path)); cursor.close(); return tx.ready(); } }