I've used Hazelcast for use cases like this with great success. It makes it relatively straightforward to implement a distributed data structure.
From: Eyal Golan <egola...@gmail.com<mailto:egola...@gmail.com>> Reply-To: "user@storm.apache.org<mailto:user@storm.apache.org>" <user@storm.apache.org<mailto:user@storm.apache.org>> Date: Thursday, December 4, 2014 at 11:40 AM To: "user@storm.apache.org<mailto:user@storm.apache.org>" <user@storm.apache.org<mailto:user@storm.apache.org>> Subject: Re: Shared static data between bolts Thanks! All the answers give me good idea. Here's why I need this list be sharable. One bolt needs the list for computation. Another bolt will periodically update the list. In other words, the list is changeable. I tried passing it in conf but there are some 3rd party libs in the wrapper. Anyway, I also need to improve the topology. Separate bolt to two etc. That way, it would be easier to handle that cache. One more question, I thought about giving hazelcast a try. Create local node and then the bolts will have clients. What do you think? Sent from my Android phone On Dec 4, 2014 9:14 PM, "Kushan Maskey" <kushan.mas...@mmillerassociates.com<mailto:kushan.mas...@mmillerassociates.com>> wrote: Hi Eyal, I had the similar issue earlier. Static objects are not a good way of passing the variables around in Storm due to clustered nature of the Storm. You will see null for all the static variables. This is how I implemented mine, for instance I wanted to pass around the server properties such and host name and username/password. I read the properties file and then created a map of these properties then set it into the Config object. Like below. In topology: Map<Stirng, Stirng> map = new HashMap(); map.put("hostname", "localhost"); map.put("username", "testuser"); map.put("password", "testpassord"); map.put("port", "1234"); Config config = new Config(); config.put("MY_MAP", map) In Bolts: public void prepare(Map stormConf, TopologyContext context) { HashMap<Stirng, Stirng> map = stormConfig.get("MY_MAP"); } This how i resolved my problem.Try that if that helps. -- Kushan Maskey 817.403.7500<tel:817.403.7500> M. Miller & Associates<http://mmillerassociates.com/> kushan.mas...@mmillerassociates.com<mailto:kushan.mas...@mmillerassociates.com> On Thu, Dec 4, 2014 at 1:01 PM, Eyal Golan <egola...@gmail.com<mailto:egola...@gmail.com>> wrote: Hi all, I am newbie with Storm and having some issues with static objects in the topology. In the main class, where I set the topology, I also set a static object. It's actually a wrapper for a collection of strings. This object needs to he shared between different bolts. It's big so I want it to be only one instance. The problem is that when a bolt tries to get this static instance: example - MyMain.Shared... It's null. Although I instantiated it in the main method. I guess I'm doing something wrong. Thanks for any assistance. Eyal Sent from my Android phone
