[
https://issues.apache.org/jira/browse/CURATOR-549?focusedWorklogId=411791&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-411791
]
ASF GitHub Bot logged work on CURATOR-549:
------------------------------------------
Author: ASF GitHub Bot
Created on: 28/Mar/20 20:14
Start Date: 28/Mar/20 20:14
Worklog Time Spent: 10m
Work Description: shayshim commented on pull request #335: [CURATOR-549]
Recipes based on Persistent Recursive Watchers
URL: https://github.com/apache/curator/pull/335#discussion_r399703987
##########
File path:
curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/CuratorCacheListenerBuilder.java
##########
@@ -0,0 +1,129 @@
+/**
+ * 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.cache;
+
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.recipes.cache.CuratorCacheListener.Type;
+import java.util.function.Consumer;
+
+public interface CuratorCacheListenerBuilder
+{
+ /**
+ * Add a standard listener
+ *
+ * @param listener listener to add
+ * @return this
+ */
+ CuratorCacheListenerBuilder forAll(CuratorCacheListener listener);
+
+ /**
+ * Add a listener only for {@link Type#NODE_CREATED}
+ *
+ * @param listener listener to add
+ * @return this
+ */
+ CuratorCacheListenerBuilder forCreates(Consumer<ChildData> listener);
+
+ @FunctionalInterface
+ interface ChangeListener
+ {
+ void event(ChildData oldNode, ChildData node);
+ }
+
+ /**
+ * Add a listener only for {@link Type#NODE_CHANGED}
+ *
+ * @param listener listener to add
+ * @return this
+ */
+ CuratorCacheListenerBuilder forChanges(ChangeListener listener);
+
+ /**
+ * Add a listener only both {@link Type#NODE_CREATED} and {@link
Type#NODE_CHANGED}
+ *
+ * @param listener listener to add
+ * @return this
+ */
+ CuratorCacheListenerBuilder forCreatesAndChanges(ChangeListener listener);
Review comment:
Instead of having these multiple combinations (and the user will still need
to check type for each event e.g. `type == NODE_CHANGED`) you could introduce
interface that allows the user implement only the methods that are interesting
for him/her, and have the burden of type -> action mapping specified in one
location for all users:
```
public interface CacheListener {
void onCacheInitialized();
void onNodeCreate(ChildData data);
void onNodeChanged(ChildData oldData, ChildData data);
void onNodeDeleted(ChildData data);
}
```
(you could introduce empty implementation for this interface for
convenience).
It is approach that doesn't embrace lambdas, but in this case of multiple
event types it might be more comfortable for users.
Note that you could do `CuratorCacheListener` -> this listener mapping as
implementation of `CuratorCacheListener` (user gives you impl of this interface
and you build around it `CuratorCacheListener` wrapper that does the mapping).
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Issue Time Tracking
-------------------
Worklog Id: (was: 411791)
Time Spent: 15h 40m (was: 15.5h)
> ZooKeeper 3.6 will add support for Persistent Recursive Watchers - Add
> Curator support
> --------------------------------------------------------------------------------------
>
> Key: CURATOR-549
> URL: https://issues.apache.org/jira/browse/CURATOR-549
> Project: Apache Curator
> Issue Type: Improvement
> Components: Client, Documentation, Framework, Recipes, Tests
> Affects Versions: 4.2.0
> Reporter: Jordan Zimmerman
> Assignee: Jordan Zimmerman
> Priority: Major
> Fix For: 5.0.0
>
> Time Spent: 15h 40m
> Remaining Estimate: 0h
>
> ZOOKEEPER-1416 will add support for Persistent Recursive Watchers. This
> feature allows Curator to re-think/re-write the various cache recipes so that
> they're simpler, use less resources and more stable.
> * Change Curator to depend on ZooKeeper 3.6.x
> * Add a new module so that backward compatibility with 3.5 is ensured
> * Add new methods corresponding to {{ZooKeeper.addWatch()}}
> * Add a new recipe that enables a fully managed Persistent watch
> * Create new Cache recipes that use the new Persistent watch recipe
> * Replace internal usages of TreeCache/PathChildrenCache/NodeCache with new
> cache recipe
> * Deprecate TreeCache/PathChildrenCache/NodeCache
> * Updated docs/tests/etc
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