Github user henrikno commented on a diff in the pull request:
https://github.com/apache/curator/pull/181#discussion_r97932637
--- Diff:
curator-recipes/src/main/java/org/apache/curator/framework/recipes/watch/InternalCuratorCache.java
---
@@ -0,0 +1,325 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.curator.framework.recipes.watch;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.cache.Cache;
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.SettableFuture;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.api.BackgroundCallback;
+import org.apache.curator.framework.api.CuratorEvent;
+import org.apache.curator.framework.api.CuratorEventType;
+import org.apache.curator.utils.ThreadUtils;
+import org.apache.curator.utils.ZKPaths;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Exchanger;
+import java.util.concurrent.atomic.AtomicInteger;
+
+class InternalCuratorCache extends CuratorCacheBase implements Watcher
+{
+ private static final CachedNode nullNode = new CachedNode();
+ private final Logger log = LoggerFactory.getLogger(getClass());
+ private final PersistentWatcher watcher;
+ private final CuratorFramework client;
+ private final String basePath;
+ private final CacheSelector cacheSelector;
+ private final CachedNodeComparator nodeComparator;
+ private final boolean sortChildren;
+ private final CacheSelector singleNodeCacheSelector = new
CacheSelector()
+ {
+ @Override
+ public boolean traverseChildren(String basePath, String fullPath)
+ {
+ return false;
+ }
+
+ @Override
+ public CacheAction actionForPath(String basePath, String fullPath)
+ {
+ return cacheSelector.actionForPath(basePath, fullPath);
+ }
+ };
+
+ InternalCuratorCache(CuratorFramework client, String path, final
CacheSelector cacheSelector, CachedNodeComparator nodeComparator, Cache<String,
CachedNode> cache, boolean sendRefreshEvents, final boolean refreshOnStart,
boolean sortChildren)
+ {
+ super(path, cache, sendRefreshEvents);
+ this.client = Objects.requireNonNull(client, "client cannot be
null");
+ this.basePath = Objects.requireNonNull(path, "path cannot be
null");
+ this.cacheSelector = Objects.requireNonNull(cacheSelector,
"cacheSelector cannot be null");
+ this.nodeComparator = Objects.requireNonNull(nodeComparator,
"nodeComparator cannot be null");
+ this.sortChildren = sortChildren;
+ watcher = new PersistentWatcher(client, path)
+ {
+ @Override
+ protected void noteWatcherReset()
+ {
+ long count = refreshCount();
+ if ( (refreshOnStart && (count == 0)) || (count > 0) )
+ {
+ internalRefresh(basePath, new
NotifyingRefresher(InternalCuratorCache.this, basePath), cacheSelector);
+ }
+ }
+ };
+ watcher.getListenable().addListener(this);
+ }
+
+ @Override
+ protected void internalStart()
+ {
+ watcher.start();
+ }
+
+ @Override
+ protected void internalClose()
+ {
+ watcher.close();
+ }
+
+ @Override
+ public void process(WatchedEvent event)
+ {
+ switch ( event.getType() )
+ {
+ default:
+ {
+ // NOP
+ break;
+ }
+
+ case NodeDeleted:
+ {
+ remove(event.getPath());
+ break;
+ }
+
+ case NodeCreated:
+ case NodeDataChanged:
+ {
+ internalRefresh(event.getPath(), new
Refresher(InternalCuratorCache.this), singleNodeCacheSelector);
+ break;
+ }
+ }
+ }
+
+ @Override
+ public CountDownLatch refreshAll()
+ {
+ return refresh(basePath);
+ }
+
+ @Override
+ public CountDownLatch refresh(String path)
+ {
+ if ( isStarted() && path.startsWith(basePath) )
+ {
+ CountDownLatch latch = new CountDownLatch(1);
+ Refresher refresher = new NotifyingRefresher(this, path,
latch);
+ internalRefresh(path, refresher, cacheSelector);
+ return latch;
+ }
+ return new CountDownLatch(0);
+ }
+
+ @VisibleForTesting
+ volatile Exchanger<Object> debugRebuildTestExchanger;
+
+ private void internalRefresh(final String path, final Refresher
refresher, final CacheSelector cacheSelector)
+ {
+ if ( !isStarted() )
+ {
+ return;
+ }
+
+ BackgroundCallback callback = new BackgroundCallback()
+ {
+ @Override
+ public void processResult(CuratorFramework client,
CuratorEvent event) throws Exception
+ {
+ if ( event.getResultCode() == 0 )
+ {
+ if ( event.getType() == CuratorEventType.GET_DATA )
+ {
+ CacheAction cacheAction =
(CacheAction)event.getContext();
+ CachedNode newNode = new
CachedNode(event.getStat(), event.getData());
+ CachedNode oldNode = putNewNode(path, cacheAction,
newNode);
+ if ( oldNode == null )
+ {
+ notifyListeners(CacheEvent.NODE_CREATED, path,
newNode);
+ }
+ else if ( !nodeComparator.isSame(newNode, oldNode)
)
+ {
+ notifyListeners(CacheEvent.NODE_CHANGED, path,
newNode);
+ }
+ }
+ else if ( event.getType() == CuratorEventType.CHILDREN
)
+ {
+ List<String> children = event.getChildren();
+ checkDeletedChildren(path, children);
+ if ( sortChildren )
+ {
+ Collections.sort(children);
+ }
+ for ( String child : children )
+ {
+ internalRefresh(ZKPaths.makePath(path, child),
refresher, cacheSelector);
+ }
+ }
+ }
+ else if ( (event.getType() == CuratorEventType.CHILDREN)
&& (event.getResultCode() == KeeperException.Code.NONODE.intValue()) )
+ {
+ checkDeletedChildren(path,
Collections.<String>emptyList());
+ }
+ else
+ {
+ log.debug("Unexpected event {} refreshing path {}",
event, path);
+ }
+ refresher.decrement();
+ if ( debugRebuildTestExchanger != null )
+ {
+ debugRebuildTestExchanger.exchange(new Object());
+ }
+ }
+ };
+
+ CacheAction cacheAction = cacheSelector.actionForPath(basePath,
path);
+ switch ( cacheAction )
+ {
+ case NOT_STORED:
+ {
+ // NOP
+ break;
+ }
+
+ case STAT_ONLY:
--- End diff --
What happens on `PATH_ONLY`?
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