Invoking the Assembler in Java

You invoke the Assembler by passing in a content item object for assembly.

If a cartridge handler exists for the input content item, the Assembler invokes that handler to process it. If not, the content item is passed through as output. Upon invoking the cartridge handler, the Assembler might in turn invoke additional cartridge handlers to process child content items. The end result of the processing cycle is an output content item representing the Assembler response.

Note

If you have purchased Oracle Guided Search, you typically query the Assembler using one of the packaged services, either with a ContentInclude item or via the Assembler service.

The examples in this topic are specific to a Spring implementation of the Assembler.

To invoke the Assembler in Java:

  1. Create an AssemblerFactory object.

    Note that the example implementation below first fetches configuration via the WebApplicationContext in the Spring framework: 

    // Get the Spring Web Application Context
 ServletContext servletCtx = this.getServletContext();
 WebApplicationContext webappCtx = 
  WebApplicationContextUtils.getRequiredWebApplicationContext(servletCtx);
 
 // Get an assembler factory and create an assembler
 AssemblerFactory assemblerFactory = 
  (AssemblerFactory)webappCtx.getBean("assemblerFactory", AssemblerFactory.class);

  2. Use the AssemblerFactory to create an Assembler: 

    Assembler assembler = assemblerFactory.createAssembler();

  3. Optionally, add event listeners to the newly-created Assembler: 

    assembler.addAssemblerEventListener(new MyLogger());

  4. Pass in the content item object to assemble: 

     ContentItem responseContentItem = assembler.assemble(myContentItem);

    Note

    You can instantiate any content item programmatically and pass it to the Assembler, but typically an assembly cycle begins with a ContentInclude or ContentSlotConfig item. Both of these methods retrieve content items created in Workbench, the former by URI, and the latter by triggering content from a folder populated in Experience Manager.

After invoking the Assembler, you may wish to serialize the response: 

// Serialize the results to JSON
 response.setCharacterEncoding("UTF-8");
 JsonSerializer serializer = new JsonSerializer(response.getWriter());
 serializer.write(responseContentItem);

The Assembler implementation included with Tools and Frameworks comes with two classes for this purpose, JsonSerializer and XmlSerializer. See the Assembler API Reference (Javadoc) for details.

Related links

A ContentInclude object specifies the URI from which to retrieve a content item.

In an authoring instance the content configuration is stored in the Endeca Configuration Repository. In a live instance, the Assembler retrieves content configuration from the live content source, specified in the configuration for the ContentIncludeHandler.

The ContentIncludeHandler retrieves the content that matches the deepest path in the URI. For example, if the request URL is http://www.example.com/browse/electronics/Cameras, the URI passed to the Assembler is /browse/electronics/Cameras. Suppose that the sitemap for this site looks like the following:

The cartridge handler first tries to retrieve the content at the exact URI. There is no content at that location, so it attempts to find the deepest matching path, which in this case is the content configuration at /browse/electronics. The Assembler then processes the content item at that location and returns the response for rendering.

Example 1. Example

The following example of a content include query retrieves page content for the Discover Electronics application with Experience Manager: 

// Construct a content include to query the content source
// for content, given the path info of the request
ContentItem contentItem = 
  new ContentInclude(request.getPathInfo());


A ContentSlotConfig object specifies one or more paths to a content folder in Experience Manager. The Assembler dynamically retrieves content items from the folder based on the trigger criteria and priorities set by the content administrator. It returns a number of content items equal to the evaluation limit configured for the specified content folder.

The Endeca Configuration Repository stores all Workbench content configuration for a given application within a content node. For example, the path to a Web → Spotlights content folder in the Discover Electronics reference application would be content/Web/Spotlights.

Example 2. Example

The following example creates a ContentSlotConfig object that is intended to populate the sidebar of an application page with three content items pulled from a Web → Spotlights content folder in Experience Manager: 

ContentItem dynamicContentItem = new ContentSlotConfig();
dynamicContentItem.setContentPaths("/content/Web/Spotlights");
dynamicContentItem.setTemplateTypes("SecondaryContent");
dynamicContentItem.setRuleLimit(3);

It specifies a template type restriction to retrieve only "SecondaryContent" for the sidebar, but does not restrict results by template ID. This allows the query to pull in content items created from multiple cartridge templates, as long as those templates have the correct type; for example, it might return a Breadcrumbs cartridge, a Record Spotlight cartridge, and a Rich Text cartridge.

The call to the Assembler is the same as for any other content item: 

 ContentItem responseContentItem = assembler.assemble(dynamicContentItem);


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