Template Examples - Locker

Author
Robert Wenzel, Engineer, Potix Corporation

Date
January XX, 2018

Version
ZK 8.5

What we want

Our goal is to avoid multiple users from editing the same resource simultaneously we need the following functionalities.

1. lock / unlock a resource

   e.g. obtain and release exclusive access to edit a specific objects properties

2. observe a resource for owner changes (LockEvents)

   it should be possible to observe the same resource with multiple concurrent users

3. react to LockEvents and update the UI

   immediately indicate availability/ownership/unavailability of a resource to the user

First we need a way to indicate our intention that we want to edit a resource and obtain a lock and vice versa return the lock when we are done editing. This is only useful if others users are aware of that condition so they don't attempt concurrent editing (and potentially losing data or producing inconsistent merged results) - means we need to observe the current lock status and finally react in the UI. e.g. by changing labels, styles, disabling/hiding/removing/adding appropriate controls.

Summary

Example Sources

The code examples are available on github in the zk-template-examples repository

zul files: https://github.com/zkoss-demo/zk-template-examples/tree/master/src/main/webapp/locker

java classes: https://github.com/zkoss-demo/zk-template-examples/tree/master/src/main/java/zk/example/template/locker

Running the Example

Clone the repo

   git clone git@github.com:zkoss-demo/zk-template-examples.git

The example war file can be built using the gradle-wrapper (on windows simply omit the prefix './'):

   ./gradlew war

Execute using gretty:

   ./gradlew appRun

Execute using jetty-runner (faster startup):

   ./gradlew startJettyRunner

Then access the example http://localhost:8080/zk-template-examples/locker/

Comments

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