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POIs there a concurrency problem here? How to test it during development?
 

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  1. POIs there a concurrency problem here? How to test it during development?
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    <p>Scenario: There exists 'n' teams who each work on their virtual 'wall' (like facebook's wall). Each team sees only their own wall and the posts on it. The posts can be edited by the author of the post or another team member (if so configured. Assuming this is indeed the case since it's a must have).</p> <p>Design/technology decisions: RESTful web-app using Restlet+ Glassfish/Java + Mysql (EDIT: Using Apache DBUtils for DB access. No ORM - seemed an overkill)</p> <p>Question: Multiple teams log on T1, T2 and T3 (say) each with some number of members. There is concurrency at the team-level data access, but not across teams - i.e., different teams access disjoint data sets. To optimize frequent read/writes from/to the DB we are considering a TeamGateway that controls access to DB for handling concurrency. The web-server would cache the data retrieved by the teams to speed up reads (and also to help updating the list of wall posts)</p> <ul> <li>Q1: Is this (TableGateway per team + cache) even required? If not how do you suggest it be handled?</li> <li>Q2: If so, does the TableGateway (for each team) need to be coded as thread safe (synchronized method)?? Let's say we have a class/registry TableGatewayFinder with a static method that returns the TableGateway to use for that particular team (using a hashmap).</li> </ul> <p>If 6 people from each of T1 - T3 log on then would ONLY 3 TableGateways be created and would it help catch concurrent writes (simple timestamp comparison before committing or a "conflict-flagged" append) and effectively manage the caching (We plan on having identity maps for the entities - there are 4-5 different entities that need to be tracked. 4 entities for a composition hierarchy and another one is associated to each of the 4)?</p> <p>How would one unit test the gateway (TDD based or after the fact)? </p> <p>Thanks in advance!</p>
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      1. POIs there a concurrency problem here? How to test it during development?
      1. USAaron Anodide
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    1. COwhat's the scale? if you have only 6 human users, you don't need any of that. if you have 6000 human users concurrently, "sharding" could help, but you need different physical machines for each wall.
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    2. COThis Question is asking WAY too many questions!
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      1. USStephen C
    3. COScale is variable for now 7-10 per team but expected to go to about 50 per team. Can be much higher but that would be read-intensive, primarily with 50 writers. But the number of teams would be large - starting with a minimum of 20
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