Oracle ADF A Status Update

Oracle posted information update for Oracle ADF - "With the continuous investment and usage of Oracle ADF inside Oracle we expect external customers will also continue to enjoy the benefits of Oracle ADF for many more years."

Read the complete post here: https://blogs.oracle.com/jdeveloperpm/oracle-adf-a-status-update

Happy to read the update, sounds positive. Thanks to Oracle for taking time and publishing this information. #adf #middleware #javascript #oracle #cloud #oraclefusion

Oracle Developer Tools - Do They Still Exist?

People are frustrated about @OracleADF @JDeveloper on social media - "ADF boat has no captain", etc. I agree @Oracle is to blame big time for such lame handling of its own Developer Tools stack. @Oracle please wake up and spend some budget on @OracleADF. Read more:

Oracle VBCS - right now this tool gets the most of Oracle focus. Supposed to offer declarative #JavaScript development experience in the Cloud. Not well received by the community. Are there any VBCS customers, please respond if yes?

Oracle APEX - comes with a very strong community (mostly backed by DB folks). But is not strategic for Oracle. More likely will be used by PL/SQL guys then by Java or Web developers. 

Oracle JET - highly promoted by Oracle. Set of opensource #JavaScript libs, glued by Oracle layer. Nice, but can't be used as a direct replacement for @OracleADF, JET is UI layer only. Oracle folks often confuse community by saying - Oracle JET is a great option to replace ADF

Oracle Forms - still alive, but obviously can't be strategic Oracle platform. A few years ago, Oracle was promoting Forms modernization to @OracleADF

Summary - Oracle Developer tools offering is weak. Lack of Oracle investment into development tools - makes Oracle developers community shrink.

ADF Faces and Client Side Value with innerHTML

In ADF Faces you can leverage the full power of JavaScript. I will explain how you could assign a value from ADF Faces component to the plain HTML div.

The sample app is available on GitHub repo. It doesn't require DB connection, you can run it straight away in Oracle JDeveloper.

Look into JSF page. I have implemented ADF Faces input component with value change listener. Below this component, there is HTML div with ID ot1. We will assign a text value to this div programmatically from JS function passClientSideValue:

JavaScript function reads the value by client ID from ADF Faces component and assigns it to the innerHTML property of HTML div:

When ADF Faces value is changed, value change listener is invoked through ADF auto-submit event. In value change listener, we extract client ID of the input component and pass it to JS function through JavaScript call from Java:

This is how the end result looks like:

In particular, this approach can be useful, when you want to bypass ADF Faces validation lifecycle and display updated value despite current validation errors in the form.

Intercepting ADF Table Column Show/Hide Event with Custom Change Manager Class

Ever wondered how to intercept ADF table column show/hide event from ADF Panel Collection component? Yes, you could use ADF MDS functionality to store user preference for table visible columns. But what if you would want to implement it yourself without using MDS? Actually, this is possible through custom persistence manager class. I will show you how.

If you don't know what I'm talking about. Check below screenshot, this popup comes out of the box with ADF Panel Collection and it helps to manage table visible columns. Pretty much useful, especially for large tables:

Obviously, we would like to store user preference and next time the user comes back to the form, he should see previously stored setup for the table columns. One way to achieve this is to use out of the box ADF MDS functionality. But what if you don't want to use it? Still possible - we can catch all changes done through Manage Columns popup in custom Change Manager class. Extend from SessionChangeManager and override only a single method - addComponentChange. This is the place where we intercept changes and could log them to DB for example (later on form load, we could read table setup and apply it before fragment is rendered):

Register custom Change Manager class in web.xml:

Manage Columns popup is out of the box functionality offered by ADF Panel Collection component:

Method addComponentChange will be automatically invoked and you should see similar output when changing table columns visibility:

Download sample application code from my GitHub repository.

ADF Performance Improvement with Nginx Compression

We are using Nginx web server for Oracle ADF WorkBetter hosted demo hosted on DigitalOcean cloud server. Nginx helps to serve web application content fast and offer improved performance. One of the important tuning options - content compression, Nginx does this job well and is simple to setup.

Content compression doesn't provide direct runtime performance, a browser would run the same code, doesn't matter it was compressed or not. But it brings improved perceived performance (which is very important), network time is way faster, because of reduced content size. Oracle ADF is a server-side framework, each request would bring content from the server - faster this content comes, means better application performance.

1. Content Compression = OFF

Let see stats, when no content compression applied (using our Oracle ADF WorkBetter hosted demo).

Page load size is 2.69 MB transferred. Finish time 1.55 s:

Navigation to the employee section generates 165.76 KB and finish time 924 ms:

Navigation to employee compensation generates 46.19 KB and finish time 494 ms:

2. Nginx compression

Compression is simple to setup in Nginx. Gzip settings are set in nginx.conf, make sure to list all content types which must be supported for compression. Restart nginx process after new settings are saved in nginx.conf:

3. Content Compression = ON

Page load size is 733.84 KB transferred. Finish time 1.48 s:

Navigation to the employee section generates 72.75 KB and finish time 917 ms:

Navigation to employee compensation generates 7.59 KB and finish time 498 ms:

JDeveloper 12c IDE Performance Boost

There is a way to optimize JDeveloper 12c IDE performance by disabling some of the features you are not using.

I was positively surprised with improved JDeveloper responsiveness after turning off some of the features. ADF BC, Task Flow, and ADF Faces wizards started to respond in a noticeably faster way. Simple change and big performance gain, awesome.

One of the strongest JDeveloper performance improvements come from disabling TopLink feature. Ironically - TopLink is an abandoned product (12.1.3 was the last release). I remember back in 2006 TopLink was very promising and it was almost becoming the default platform for ADF Model. One of the old blog posts written by me related to TopLink - External Transaction Service in Oracle TopLink. But luckily it was overshadowed by ADF BC.

These are the features I disabled in my JDeveloper to get performance gain:

Announcing Hosting for Oracle ADF Rich Client and Oracle ADF WorkBetter Demos

If you are curious about how Oracle ADF works or want to explore a rich set of ADF Faces components - welcome to access Oracle ADF demo apps hosted on our cloud server.

We launched a dedicated website Oracle ADF Components. Hosted demos:

1. ADF Faces Rich Client
2. ADF Work Better

These demo apps can be downloaded from Oracle, you could run them on your own environment too. But sometimes it is useful to have apps online for quick access.

Oracle ADF BC Reusing SQL from Statement Cache

Oracle ADF BC by default is trying to reuse prepared SQL query from statement cache. It works this way when ADF BC runs with DB pooling off (jbo.doconnectionpooling=false). Normally we tune ADF application to run with DB pooling on (jbo.doconnectionpooling=true), this allows to release unused DB connection back to the pool when a request is completed (and in this case, statement cache will not be used anyway). If View Object is re-executed multiple times during the same request - in this situation, it will use statement cache too.

However, there are cases when for specific View Object you would want to turn off statement cache usage. There could be multiple reasons for this - for example, you are getting Closed Statement error after it tries to execute SQL for statement obtained from statement cache. Normally you would be fine using statement cache, but as I said - there are those special cases.

We are lucky because there is a way to override statement cache usage behavior. This can be done in View Object implementation class either for particular View Object or in the generic class.

After View Object was executed, check the log. If this is not the first execution, you will see log message - "reusing defined prepared statement". This means SQL will be reused from statement cache:

To control this behavior, override getPreparedStatement method:

We create new prepared statement in this method, instead of reusing one from the cache.

As a result - each time View Object is executed, there is no statement cache usage:

Download sample application from GitHub repo.

Understanding Attributes Enum in ADF BC Row Class

Did you ever wonder why Attributes Enum is generated by JDeveloper in Entity or View Row class? Attributes Enum holds a collection of attribute names and there is a set of static variables with attribute indexes. These indexes are used to locate attribute in getter/setter. Attributes Enum is a structure which is required for JDeveloper on design time to generate Java code. On runtime Attributes Enum is needed only as long as you are using a static variable index in the getter/setter.

Attributes Enum and list of static indexes in View Row class:

Static index is used in the getter/setter to access attribute:

Attributes Enum is mimicking attributes order in the VO/EO. You can think about it as about attributes metadata. It is not mandatory to use index from Attributes Enum. In some use cases, you could get attribute index directly from VO/EO Def and use it to access attribute:

First name is fetched correctly using overridden getter:

Download sample code from GitHub

Oracle ADF + Jasper Visualize.js = Awesome

This week I was working on a task to integrate Jasper Visualize.js into Oracle ADF application JSF page fragment. I must say integration was successful and Jasper report renders very well in Oracle ADF screen with the help of Visualize.js. Great thing about Visualize.js - it renders report in ADF page through client side HTML/JS, there is no iFrame. Report HTML structure is included into HTML generated by ADF, this allows to use CSS to control report size and make it responsive.

To prove integration, I was using ADF application with multiple regions - ADF Multi Task Flow Binding and Tab Order. Each region is loaded with ADF Faces tab:

One of the tabs display region with Jasper report, rendered with Visualize.js:

Check client side generated code. You should see HTML from Visualize.js inside ADF generated HTML structure:

It is straightforward to render Jasper report with Visualize.js in Oracle ADF. Add JS resource reference to Visualize.js library, define DIV where report supposed to be rendered. Add Visualize.js function to render report from certain path, etc.:

Sample code is available on my GitHub repo.

ADF 19 Demo from Oracle Open World San Francisco

ADF 19 was announced by Shay Shmeltzer at OOW'18. Expect to have many bug fixes and improvements in this release. I have recorded two videos demonstrating:

1. Client side responsive layout
2. Vertical tabs with text labels
3. ADF list with swipe option
4. New client side date components
5. Client LOVs with search and custom result list

Part I demo:

Part II demo:

Slides from the session:

1. Oracle ADF 19 - What's Next

2. What's New in ADF Faces

ADF Task Flow Performance Boost with JET UI Shell Wrapper

ADF application with UI Shell and ADF Task Flows rendered in dynamic tabs would not offer instant switch from one tab to another experience. Thats because tab switch request goes to the server and only when browser gets response - tab switch happens. There is more to this - even if tab in ADF is not currently active (tab is disclosed), tab content (e.g. region rendered from ADF Task Flow) still may participate in the request processing. If user opens many tabs, this could result in slightly slower request processing time overall.

ADF allows to render ADF Task Flows directly by accessing them through URL, if it is configured with page support on the root level. ADF Task Flow can be accessed by URL, this means we can include it into iframe. Imagine using iframe for each tab and rendering ADF Task Flows inside. This will enable ADF Task Flow independent processing in each tab, similar to opening them in separate browser tab.

Iframe can be managed in Oracle JET, using plain JavaScript and HTML code. My sample implements dynamic JET tabs with iframe support. Iframe renders ADF Task Flow. While navigating between tabs, I simply hide/show iframes, this allows to keep the state of ADF Task Flow and return to the same state, when opening back the tab. Huge advantage in this case - tab navigation and switching between tabs with ADF Task Flows works very fast - it takes only client time processing. Look at this recorded gif, where I navigate between tabs with ADF content:

Main functions are listed below.

1. Add dynamic iframe. Here we check if frame for given ADF Task Flow is already created, if no we create it and append to HTML element

2. Select iframe, when switching tabs. Hide all frames first, select frame which belongs to the selected tab

3. Remove iframe. Remove frame, when tab is closed

4. Select frame after remove. This method helps to set focus to the next frame, after current tab was removed

We can control when iframe or regular JET module is rendered, by using flag computed function assigned to main div:

In this app I have defined static URL's for displayed ADF Task Flows. Same can be loaded by fetching menu, etc.:

To be able to load ADF Task Flow by URL, make sure to use ADF Task Flow with page (you can include ADF region with fragments into that page). Set url-invoke-allowed property:

This is how it looks like. By default, JET dashboard module is displayed, select item from the menu list to load tab with ADF Task Flow:

JET tab rendering iframe with ADF table:

You can monitor ADF content loading in iframe within JET application:

JET tab rendering iframe with ADF form:

Download sample app from GitHub repository.

Data Conflict Solution for ADF BC REST with Versioning

I would like to share sample solution for data conflict processing in ADF BC REST using versioning. When multiple users are editing concurrently the same data row - it is important to inform user before overriding changes already committed by another user. There are other approaches to implement data conflict control, you should evaluate if solution explained below is suitable for your use case, before applying it.

Sample code can be obtained from GitHub repository.

I'm using custom change indicator property, to evaluate if client data is expired. Change indicator value is sent to the client together with request data. PATCH request must include current client side change indicator value, if change indicator will match value in backend - PATCH is allowed, otherwise new change indicator will be returned to the client and response will be marked with 409 Conflict status code. Based on this, client could decide either to resubmit PATCH request with new change indicator and overwrite current data in DB or refresh client side data and try to submit changes later.

In this example - PATCH was executed with valid change indicator, response status is 200 OK. New change indicator value is returned to the client (it should be submitted for the next PATCH call for current row):

To test data change conflict, I would go directly to DB and change same record. Change indicator will be updated too:

Client doesn't know about change indicator update (data was changed by another user). Client will include currently known change indicator value and execute PATCH. This will result in 409 Conflict status. Backend returns latest change indicator value in the response:

Data wasn't updated, PATCH request was stopped on the backend:

Client knows latest change indicator value and can submit it again - this time successful (no one else changed data in the meantime):

Status 200 OK is returned, along with new change indicator value. Data is changed in DB as expected:

Backend implementation is not complex. You need DB trigger, which will get value from DB sequence and assign it for each changed row:

ADF BC REST includes change indicator attribute, it is marked with Refresh on Update support. This allows to get latest value assigned from DB trigger and return it to the client:

In doDML method we compare change indicator attribute value currently stored in DB and the one which comes from the client. If values do not match (client doesn't have the latest value) - update is not allowed:

When update is not allowed, we also must change HTTP response code to be 409 Conflict. This will allow to execute error callback on client side and take required action to process data conflict on the client. HTTP response code is set from custom ADF BC REST filter: