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Learning Pentaho CTools

You're reading from   Learning Pentaho CTools Acquire finesse with CTools features and build rich and custom analytics solutions using Pentaho

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Product type Paperback
Published in May 2016
Publisher Packt
ISBN-13 9781785283420
Length 388 pages
Edition 1st Edition
Languages
Tools
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Author (1):
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Miguel Gaspar Miguel Gaspar
Author Profile Icon Miguel Gaspar
Miguel Gaspar
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Toc

Table of Contents (12) Chapters Close

Preface 1. Getting Started with CTools FREE CHAPTER 2. Acquiring Data with CDA 3. Building the Dashboard Using CDF 4. Leverage the Process with CDE 5. Applying Filters to the Dashboard 6. Tables, Templates, Exports, and Text Components 7. Advanced Concepts Using CDF and CDE 8. Visualizations Using CCC 9. Pentaho App Builder 10. Embed, Deploy, and Debug Index

Using preChange and postChange


Now it's time to cover preChange and postChange. These two functions will only be available in components whose main purpose is to be used as filters. Examples of this are select, input, date range, radio button, button, multi button, and so on.

Every component where we can set a parameter to store the selections and the lifecycle of the component will trigger fireChange to that parameter. We have the option to specify the function that will be executed both before this happens and after applying the changes to the parameter, preChange and postChange. Take a look at following image:

As you can figure out, that the first function, the preChange function, can be used to execute the code that can validate the options and take some actions before changing the parameter value. Can be used to prepare something before other components starts to execute because they are listening to that same parameter. The other postExecution function, can be used to perform operations...

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