javax.mvc.engine

Interface ViewEngine

public interface ViewEngine

View engines are responsible for processing views and are discovered using CDI. Implementations must inject all instances of this interface, and process a view as follows:

1. Gather the set of candidate view engines by calling supports(String) and discarding engines that return false.
2. Sort the resulting set of candidates using priorities. View engines can be decorated with Priority to indicate their priority; otherwise the priority is assumed to be Priorities.DEFAULT.
3. If more than one candidate is available, choose one in an implementation-defined manner.
4. Fire a BeforeProcessViewEvent event.
5. Call method processView(ViewEngineContext) to process view.
6. Fire a AfterProcessViewEvent event.

The default view engines for JSPs and Facelets use file extensions to determine support. Namely, the default JSP view engine supports views with extensions jsp and jspx, and the one for Facelets supports views with extension xhtml.

Since:

1.0

Author:

Santiago Pericas-Geertsen

See Also:

Priority, BeforeProcessViewEvent

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_VIEW_FOLDER Default value for property VIEW_FOLDER.
static String	VIEW_FOLDER Name of property that can be set in an application's Configuration to override the root location for views in an archive.

Method Summary

Modifier and Type	Method and Description
void	processView(ViewEngineContext context) Process a view given a ViewEngineContext.
boolean	supports(String view) Returns true if this engine can process the view or false otherwise.

Field Detail

VIEW_FOLDER

static final String VIEW_FOLDER

Name of property that can be set in an application's Configuration to override the root location for views in an archive.

See Also:

Application.getProperties(), Constant Field Values

DEFAULT_VIEW_FOLDER

static final String DEFAULT_VIEW_FOLDER

Default value for property VIEW_FOLDER.

See Also:

Constant Field Values

Method Detail

supports

boolean supports(String view)

Returns true if this engine can process the view or false otherwise.

Parameters:

view - the view.

Returns:

outcome of supports test.

processView

void processView(ViewEngineContext context)
          throws ViewEngineException

Process a view given a ViewEngineContext. Processing a view involves merging the model and template data and writing the result to an output stream.

Following the Java EE threading model, the underlying view engine implementation must support this method being called by different threads. Any resources allocated during view processing must be released before the method returns.

Parameters:

context - the context needed for processing.

Throws:

ViewEngineException - if an error occurs during processing.