Java tutorial
/* * 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.mdsal.dom.broker; import com.google.common.base.Preconditions; import com.google.common.collect.BiMap; import com.google.common.collect.ImmutableBiMap; import com.google.common.collect.ImmutableBiMap.Builder; import com.google.common.collect.ImmutableMap; import com.google.common.collect.ImmutableSet; import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.LinkedList; import java.util.Map; import java.util.Map.Entry; import java.util.Queue; import java.util.Set; import javax.annotation.concurrent.GuardedBy; import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier; import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer; import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerBusyException; import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerException; import org.opendaylight.mdsal.dom.api.DOMDataTreeShard; import org.opendaylight.mdsal.dom.api.DOMDataTreeWriteTransaction; import org.opendaylight.mdsal.dom.spi.store.DOMStore; import org.opendaylight.mdsal.dom.spi.store.DOMStoreTransactionChain; import org.opendaylight.mdsal.dom.spi.store.DOMStoreWriteTransaction; import org.slf4j.Logger; import org.slf4j.LoggerFactory; final class ShardedDOMDataTreeProducer implements DOMDataTreeProducer { private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMDataTreeProducer.class); private final BiMap<DOMDataTreeShard, DOMStoreTransactionChain> shardToChain; private final Map<DOMDataTreeIdentifier, DOMDataTreeShard> idToShard; private final ShardedDOMDataTree dataTree; @GuardedBy("this") private Map<DOMDataTreeIdentifier, DOMDataTreeProducer> children = Collections.emptyMap(); @GuardedBy("this") private DOMDataTreeWriteTransaction openTx; @GuardedBy("this") private boolean closed; @GuardedBy("this") private ShardedDOMDataTreeListenerContext<?> attachedListener; ShardedDOMDataTreeProducer(final ShardedDOMDataTree dataTree, final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap, final Set<DOMDataTreeShard> shards) { this.dataTree = Preconditions.checkNotNull(dataTree); // Create shard -> chain map final Builder<DOMDataTreeShard, DOMStoreTransactionChain> cb = ImmutableBiMap.builder(); final Queue<Exception> es = new LinkedList<>(); for (final DOMDataTreeShard s : shards) { if (s instanceof DOMStore) { try { final DOMStoreTransactionChain c = ((DOMStore) s).createTransactionChain(); LOG.trace("Using DOMStore chain {} to access shard {}", c, s); cb.put(s, c); } catch (final Exception e) { LOG.error("Failed to instantiate chain for shard {}", s, e); es.add(e); } } else { LOG.error("Unhandled shard instance type {}", s.getClass()); } } this.shardToChain = cb.build(); // An error was encountered, close chains and report the error if (shardToChain.size() != shards.size()) { for (final DOMStoreTransactionChain c : shardToChain.values()) { try { c.close(); } catch (final Exception e) { LOG.warn("Exception raised while closing chain {}", c, e); } } final IllegalStateException e = new IllegalStateException("Failed to completely allocate contexts", es.poll()); while (!es.isEmpty()) { e.addSuppressed(es.poll()); } throw e; } idToShard = ImmutableMap.copyOf(shardMap); } @Override public synchronized DOMDataTreeWriteTransaction createTransaction(final boolean isolated) { Preconditions.checkState(!closed, "Producer is already closed"); Preconditions.checkState(openTx == null, "Transaction %s is still open", openTx); // Allocate backing transactions final Map<DOMDataTreeShard, DOMStoreWriteTransaction> shardToTx = new HashMap<>(); for (final Entry<DOMDataTreeShard, DOMStoreTransactionChain> e : shardToChain.entrySet()) { shardToTx.put(e.getKey(), e.getValue().newWriteOnlyTransaction()); } // Create the ID->transaction map final ImmutableMap.Builder<DOMDataTreeIdentifier, DOMStoreWriteTransaction> b = ImmutableMap.builder(); for (final Entry<DOMDataTreeIdentifier, DOMDataTreeShard> e : idToShard.entrySet()) { b.put(e.getKey(), shardToTx.get(e.getValue())); } final ShardedDOMDataWriteTransaction ret = new ShardedDOMDataWriteTransaction(this, b.build()); openTx = ret; return ret; } @GuardedBy("this") private boolean haveSubtree(final DOMDataTreeIdentifier subtree) { for (final DOMDataTreeIdentifier i : idToShard.keySet()) { if (i.contains(subtree)) { return true; } } return false; } @GuardedBy("this") private DOMDataTreeProducer lookupChild(final DOMDataTreeIdentifier s) { for (final Entry<DOMDataTreeIdentifier, DOMDataTreeProducer> e : children.entrySet()) { if (e.getKey().contains(s)) { return e.getValue(); } } return null; } @Override public synchronized DOMDataTreeProducer createProducer(final Collection<DOMDataTreeIdentifier> subtrees) { Preconditions.checkState(!closed, "Producer is already closed"); Preconditions.checkState(openTx == null, "Transaction %s is still open", openTx); for (final DOMDataTreeIdentifier s : subtrees) { // Check if the subtree was visible at any time Preconditions.checkArgument(haveSubtree(s), "Subtree %s was never available in producer %s", s, this); // Check if the subtree has not been delegated to a child final DOMDataTreeProducer child = lookupChild(s); Preconditions.checkArgument(child == null, "Subtree %s is delegated to child producer %s", s, child); // Check if part of the requested subtree is not delegated to a child. for (final DOMDataTreeIdentifier c : children.keySet()) { if (s.contains(c)) { throw new IllegalArgumentException(String.format( "Subtree %s cannot be delegated as it is superset of already-delegated %s", s, c)); } } } final DOMDataTreeProducer ret = dataTree.createProducer(this, subtrees); final ImmutableMap.Builder<DOMDataTreeIdentifier, DOMDataTreeProducer> cb = ImmutableMap.builder(); cb.putAll(children); for (final DOMDataTreeIdentifier s : subtrees) { cb.put(s, ret); } children = cb.build(); return ret; } boolean isDelegatedToChild(DOMDataTreeIdentifier path) { for (final DOMDataTreeIdentifier c : children.keySet()) { if (c.contains(path)) { return true; } } return false; } @Override public synchronized void close() throws DOMDataTreeProducerException { if (!closed) { if (openTx != null) { throw new DOMDataTreeProducerBusyException(String.format("Transaction %s is still open", openTx)); } closed = true; dataTree.destroyProducer(this); } } static DOMDataTreeProducer create(final ShardedDOMDataTree dataTree, final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) { /* * FIXME: we do not allow multiple multiple shards in a producer because we do not implement the * synchronization primitives yet */ final Set<DOMDataTreeShard> shards = ImmutableSet.copyOf(shardMap.values()); if (shards.size() > 1) { throw new UnsupportedOperationException("Cross-shard producers are not supported yet"); } return new ShardedDOMDataTreeProducer(dataTree, shardMap, shards); } Set<DOMDataTreeIdentifier> getSubtrees() { return idToShard.keySet(); } synchronized void cancelTransaction(final ShardedDOMDataWriteTransaction transaction) { if (!openTx.equals(transaction)) { LOG.warn("Transaction {} is not open in producer {}", transaction, this); return; } LOG.debug("Transaction {} cancelled", transaction); openTx = null; } synchronized void transactionSubmitted(ShardedDOMDataWriteTransaction transaction) { Preconditions.checkState(openTx.equals(transaction)); openTx = null; } synchronized void boundToListener(ShardedDOMDataTreeListenerContext<?> listener) { // FIXME: Add option to dettach Preconditions.checkState(this.attachedListener == null, "Producer %s is already attached to other listener.", listener.getListener()); this.attachedListener = listener; } }