Renderer

java.lang.Object
- jakarta.faces.render.Renderer<T>

Type Parameters:

T - The component class.

Direct Known Subclasses:

RendererWrapper
```
public abstract class Renderer<T extends UIComponent>
extends java.lang.Object
```
A Renderer converts the internal representation of UIComponents into the output stream (or writer) associated with the response we are creating for a particular request. Each Renderer knows how to render one or more UIComponent types (or classes), and advertises a set of render-dependent attributes that it recognizes for each supported UIComponent.

Families of Renderers are packaged as a RenderKit, and together support the rendering of all of the UIComponents in a view associated with a FacesContext. Within the set of Renderers for a particular RenderKit, each must be uniquely identified by the rendererType property.

Individual Renderer instances will be instantiated as requested during the rendering process, and will remain in existence for the remainder of the lifetime of a web application. Because each instance may be invoked from more than one request processing thread simultaneously, they MUST be programmed in a thread-safe manner.

If the ListenerFor annotation is attached to the class definition of a Renderer, that class must also implement ComponentSystemEventListener, and the action pertaining to the processing of ResourceDependency on a Renderer described in ListenerFor must be taken.

If the ResourceDependency annotation is attached to the class definition of a Renderer, the action pertaining to the processing of ResourceDependency on a Renderer described in UIComponent.getChildren() must be taken.

The generic parameter T represents the component class.

Field Summary

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`PASSTHROUGH_RENDERER_LOCALNAME_KEY` The key in the component passthrough attributes `Map` for the localName of the element corresponding to the component.

Constructor Summary

Constructors
Constructor and Description

Renderer()

Constructors
Constructor and Description
`Renderer()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.lang.String`	`convertClientId(FacesContext context, java.lang.String clientId)` Convert the component generated client id to a form suitable for transmission to the client.
`void`	`decode(FacesContext context, T component)` Decode any new state of the specified `UIComponent` from the request contained in the specified `FacesContext`, and store that state on the `UIComponent`.
`void`	`encodeBegin(FacesContext context, T component)` Render the beginning specified `UIComponent` to the output stream or writer associated with the response we are creating.
`void`	`encodeChildren(FacesContext context, T component)` Render the child components of this `UIComponent`, following the rules described for `encodeBegin()` to acquire the appropriate value to be rendered.
`void`	`encodeEnd(FacesContext context, T component)` Render the ending of the current state of the specified `UIComponent`, following the rules described for `encodeBegin()` to acquire the appropriate value to be rendered.
`java.lang.Object`	`getConvertedValue(FacesContext context, UIComponent component, java.lang.Object submittedValue)` Attempt to convert previously stored state information into an object of the type required for this component (optionally using the registered `Converter` for this component, if there is one).
`boolean`	`getRendersChildren()` Return a flag indicating whether this `Renderer` is responsible for rendering the children the component it is asked to render.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PASSTHROUGH_RENDERER_LOCALNAME_KEY
```
public static final java.lang.String PASSTHROUGH_RENDERER_LOCALNAME_KEY
```
    The key in the component passthrough attributes Map for the localName of the element corresponding to the component.
    
    Since:
    
    2.2
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Renderer
```
public Renderer()
```
- Method Detail
  - decode
```
public void decode(FacesContext context,
                   T component)
```
    Decode any new state of the specified UIComponent from the request contained in the specified FacesContext, and store that state on the UIComponent.
    
    During decoding, events may be enqueued for later processing (by event listeners that have registered an interest), by calling queueEvent() on the associated UIComponent.
    
    Parameters:
    
    context - FacesContext for the request we are processing
    
    component - UIComponent to be decoded.
    
    Throws:
    
    java.lang.NullPointerException - if context or component is null
  - encodeBegin
```
public void encodeBegin(FacesContext context,
                        T component)
                 throws java.io.IOException
```
    Render the beginning specified UIComponent to the output stream or writer associated with the response we are creating. If the conversion attempted in a previous call to getConvertedValue() for this component failed, the state information saved during execution of decode() should be used to reproduce the incorrect input.
    
    Parameters:
    
    context - FacesContext for the request we are processing
    
    component - UIComponent to be rendered
    
    Throws:
    
    java.io.IOException - if an input/output error occurs while rendering
    
    java.lang.NullPointerException - if context or component is null
  - encodeChildren
```
public void encodeChildren(FacesContext context,
                           T component)
                    throws java.io.IOException
```
    Render the child components of this UIComponent, following the rules described for encodeBegin() to acquire the appropriate value to be rendered. This method will only be called if the rendersChildren property of this component is true.
    
    Parameters:
    
    context - FacesContext for the response we are creating
    
    component - UIComponent whose children are to be rendered
    
    Throws:
    
    java.io.IOException - if an input/output error occurs while rendering
    
    java.lang.NullPointerException - if context or component is null
  - encodeEnd
```
public void encodeEnd(FacesContext context,
                      T component)
               throws java.io.IOException
```
    Render the ending of the current state of the specified UIComponent, following the rules described for encodeBegin() to acquire the appropriate value to be rendered.
    
    Parameters:
    
    context - FacesContext for the response we are creating
    
    component - UIComponent to be rendered
    
    Throws:
    
    java.io.IOException - if an input/output error occurs while rendering
    
    java.lang.NullPointerException - if context or component is null
  - convertClientId
```
public java.lang.String convertClientId(FacesContext context,
                                        java.lang.String clientId)
```
    Convert the component generated client id to a form suitable for transmission to the client.
    
    The default implementation returns the argument clientId unchanged.
    
    Parameters:
    
    context - FacesContext for the current request
    
    clientId - the client identifier to be converted to client a specific format.
    
    Returns:
    
    the converted clientId
    
    Throws:
    
    java.lang.NullPointerException - if context or clientId is null
  - getRendersChildren
```
public boolean getRendersChildren()
```
    Return a flag indicating whether this Renderer is responsible for rendering the children the component it is asked to render. The default implementation returns false.
    
    Returns:
    
    the current value of the flag
  - getConvertedValue
```
public java.lang.Object getConvertedValue(FacesContext context,
                                          UIComponent component,
                                          java.lang.Object submittedValue)
                                   throws ConverterException
```
    Attempt to convert previously stored state information into an object of the type required for this component (optionally using the registered Converter for this component, if there is one). If conversion is successful, the new value should be returned from this method; if not, a ConverterException should be thrown.
    
    Parameters:
    
    context - FacesContext for the request we are processing
    
    component - UIComponent to be decoded.
    
    submittedValue - a value stored on the component during decode.
    
    Returns:
    
    the converted value
    
    Throws:
    
    ConverterException - if the submitted value cannot be converted successfully.
    
    java.lang.NullPointerException - if context or component is null

Class Renderer<T extends UIComponent>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PASSTHROUGH_RENDERER_LOCALNAME_KEY

Constructor Detail

Renderer

Method Detail

decode

encodeBegin

encodeChildren

encodeEnd

convertClientId

getRendersChildren

getConvertedValue