Package org.apache.tapestry5

## Interface ComponentResources

- All Superinterfaces:
    `ComponentResourcesCommon`, `Locatable`
  All Known Subinterfaces:
    `InternalComponentResources`
  All Known Implementing Classes:
    `InternalComponentResourcesImpl`

      public interface ComponentResources
      extends ComponentResourcesCommon

  Provides a component instance with the resources provided by the framework. In many circumstances, the resources object can be considered the component itself; in others, it is the component property, an instance of a class provided by the application developer (though transformed in many ways while being loaded) that is the true component. In reality, it is the combination of the resources object with the user class instance that forms the components; neither is useful without the other.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods Deprecated Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `addPageLifecycleListener​(PageLifecycleListener listener)` | Deprecated. In 5.3.4, use `getPageLifecycleCallbackHub()` instead
    `void` | `discardPersistentFieldChanges()` | Discards all persistent field changes for the page containing the component.
    `AnnotationProvider` | `getAnnotationProvider​(String parameterName)` | Returns an annotation provider, used to obtain annotations related to the parameter.
    `Resource` | `getBaseResource()` | Returns the base resource for the component, which will represent the class's location within the classpath (this is used to resolve relative assets).
    `Block` | `getBlockParameter​(String parameterName)` | Used to access an informal parameter that's a Block.
    `Type` | `getBoundGenericType​(String parameterName)` | Returns the generic type of the bound parameter, or null if the parameter is not bound.
    `Class` | `getBoundType​(String parameterName)` | Returns the actual type of the bound parameter, or null if the parameter is not bound.
    `Component` | `getComponent()` | Returns the component this object provides resources for.
    `ComponentModel` | `getComponentModel()` | Returns the component model object that defines the behavior of the component.
    `Component` | `getContainer()` | Returns the component which contains this component, or null for the root component.
    `Messages` | `getContainerMessages()` | Returns the `Messages` from the container, or null if this is the root component (with no container).
    `ComponentResources` | `getContainerResources()` | Returns the `ComponentResources` for the container, or null if the this is the root component (that has no container).
    `String` | `getElementName()` | Returns the name of element that represents the component in its template, or null if not known.
    `Component` | `getEmbeddedComponent​(String embeddedId)` | Returns an embedded component, given the component's id.
    `<T> T` | `getInformalParameter​(String name, Class<T> type)` | Reads an informal parameter and coerces the bound value to the indicated type.
    `List<String>` | `getInformalParameterNames()` | Returns a list of the names of any informal parameters bound to this component.
    `Messages` | `getMessages()` | Returns the message catalog for this component.
    `Component` | `getPage()` | Returns the page that contains this component.
    `PageLifecycleCallbackHub` | `getPageLifecycleCallbackHub()` | Provides access to an object that can be used to register callbacks for page lifecycle events.
    `<T extends Annotation> T` | `getParameterAnnotation​(String parameterName, Class<T> annotationType)` | Obtains an annotation provided by a parameter.
    `Object` | `getRenderVariable​(String name)` | Returns a previously stored render variable.
    `boolean` | `isBound​(String parameterName)` | Returns true if the named parameter is bound, false if not.
    `boolean` | `isMixin()` | Returns true if these resources represent a mixin to another component.
    `void` | `removePageLifecycleListener​(PageLifecycleListener listener)` | Deprecated. in 5.3.4, not necessary with `PageLifecycleCallbackHub.addPageLoadedCallback(Runnable)`.
    `void` | `renderInformalParameters​(MarkupWriter writer)` | Indentifies all parameters that are not formal parameters and writes each as a attribute/value pair into the current element of the markup writer.
    `void` | `storeRenderVariable​(String name, Object value)` | Stores a render variable, accessible with the provided name.

    - ### Methods inherited from interface org.apache.tapestry5.ComponentResourcesCommon

      `createEventLink, createFormEventLink, findBlock, getBlock, getBody, getCompleteId, getElementName, getId, getLocale, getLogger, getNestedId, getPageName, getResourceSelector, hasBody, isRendering, triggerContextEvent, triggerEvent`

    - ### Methods inherited from interface org.apache.tapestry5.commons.Locatable

      `getLocation`

- - ### Method Detail

    - #### getBaseResource

          Resource getBaseResource()

      Returns the base resource for the component, which will represent the class's location within the classpath (this is used to resolve relative assets).

    - #### getComponentModel

          ComponentModel getComponentModel()

      Returns the component model object that defines the behavior of the component.

    - #### getComponent

          Component getComponent()

      Returns the component this object provides resources for.

    - #### getContainer

          Component getContainer()

      Returns the component which contains this component, or null for the root component. For mixins, this returns the component to which the mixin is attached.

    - #### getContainerResources

          ComponentResources getContainerResources()

      Returns the `ComponentResources` for the container, or null if the this is the root component (that has no container). As a special case, for a mixin, this returns the core component's resources.

    - #### getContainerMessages

          Messages getContainerMessages()

      Returns the `Messages` from the container, or null if this is the root component (with no container). As a special case, for a mixin, this return the core component's messages.

    - #### getPage

          Component getPage()

      Returns the page that contains this component. Technically, the page itself is an internal object in Tapestry and this returns the root component of the actual page, but from an application developer point of view, this is the page.

    - #### getEmbeddedComponent

          Component getEmbeddedComponent​(String embeddedId)

      Returns an embedded component, given the component's id.
      Parameters:
        `embeddedId` - selects the embedded component (case is ignored)
      Throws:
        `UnknownValueException` - if this component does not contain a component with the given id

    - #### isBound

          boolean isBound​(String parameterName)

      Returns true if the named parameter is bound, false if not.

    - #### getParameterAnnotation

          <T extends Annotation> T getParameterAnnotation​(String parameterName,
                                                          Class<T> annotationType)

      Obtains an annotation provided by a parameter.
      Parameters:
        `parameterName` - name of parameter to search for the annotation
        `annotationType` - the type of annotation
      Returns:
        the annotation if found or null otherwise

    - #### renderInformalParameters

          void renderInformalParameters​(MarkupWriter writer)

      Indentifies all parameters that are not formal parameters and writes each as a attribute/value pair into the current element of the markup writer.
      Parameters:
        `writer` - to which `attributes` will be written

    - #### getMessages

          Messages getMessages()

      Returns the message catalog for this component.

    - #### getBoundType

          Class getBoundType​(String parameterName)

      Returns the actual type of the bound parameter, or null if the parameter is not bound. This is primarily used with property bindings, and is used to determine the actual type of the property, rather than the type of parameter (remember that type coercion automatically occurs, which can mask significant differences between the parameter type and the bound property type).
      Parameters:
        `parameterName` - used to select the parameter (case is ignored)
      Returns:
        the type of the bound parameter, or null if the parameter is not bound
      See Also:
        `Binding.getBindingType()`

    - #### getBoundGenericType

          Type getBoundGenericType​(String parameterName)

      Returns the generic type of the bound parameter, or null if the parameter is not bound. This is useful for when the parameter is bound to a generic property (eg java.util.List) to determine the element type.
      Parameters:
        `parameterName` - used to select the parameter (case is ignored)
      Returns:
        the generic type of the bound parameter, or null if the parameter is not bound
      See Also:
        `Binding.getBindingType()`

    - #### getAnnotationProvider

          AnnotationProvider getAnnotationProvider​(String parameterName)

      Returns an annotation provider, used to obtain annotations related to the parameter.
      Parameters:
        `parameterName` - used to select the parameter (case is ignored)
      Returns:
        the annotation provider, or null if the parameter is not bound

    - #### getBlockParameter

          Block getBlockParameter​(String parameterName)

      Used to access an informal parameter that's a Block.
      Parameters:
        `parameterName` - the name of the informal parameter (case is ignored)
      Returns:
        the informal Block parameter, or null if not bound

    - #### getRenderVariable

          Object getRenderVariable​(String name)

      Returns a previously stored render variable.
      Parameters:
        `name` - of the variable (case will be ignored)
      Returns:
        the variable's value
      Throws:
        `IllegalArgumentException` - if the name doesn't correspond to a stored value

    - #### storeRenderVariable

          void storeRenderVariable​(String name,
                                   Object value)

      Stores a render variable, accessible with the provided name.
      Parameters:
        `name` - of value to store
        `value` - value to store (may not be null)
      Throws:
        `IllegalStateException` - if the component is not currently rendering

    - #### addPageLifecycleListener

          void addPageLifecycleListener​(PageLifecycleListener listener)

      Deprecated.
      In 5.3.4, use `getPageLifecycleCallbackHub()` instead
      Adds a listener object that will be notified about page lifecycle events.

    - #### getPageLifecycleCallbackHub

          PageLifecycleCallbackHub getPageLifecycleCallbackHub()

      Provides access to an object that can be used to register callbacks for page lifecycle events.
      Returns:
        the hub
      Since:
        5.3.4

    - #### removePageLifecycleListener

          void removePageLifecycleListener​(PageLifecycleListener listener)

      Deprecated.
      in 5.3.4, not necessary with `PageLifecycleCallbackHub.addPageLoadedCallback(Runnable)`.
      Removes a previously added listener.
      Since:
        5.2.0

    - #### discardPersistentFieldChanges

          void discardPersistentFieldChanges()

      Discards all persistent field changes for the page containing the component. Changes are eliminated from persistent storage (such as the `Session`) which will take effect in the next request (the attached page instance is not affected).

    - #### getElementName

          String getElementName()

      Returns the name of element that represents the component in its template, or null if not known.
      Returns:
        the element name or null

    - #### getInformalParameterNames

          List<String> getInformalParameterNames()

      Returns a list of the names of any informal parameters bound to this component.
      Returns:
        the name sorted alphabetically
      See Also:
        `SupportsInformalParameters`

    - #### getInformalParameter

          <T> T getInformalParameter​(String name,
                                     Class<T> type)

      Reads an informal parameter and coerces the bound value to the indicated type.
      Parameters:
        `name` - name of informal parameter
        `type` - output value type
      Returns:
        instance of type

    - #### isMixin

          boolean isMixin()

      Returns true if these resources represent a mixin to another component. The component is the container of this resources.
      Since:
        5.2.0