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javax.portlet
Class GenericPortlet

java.lang.Object
  extended by javax.portlet.GenericPortlet

All Implemented Interfaces
EventPortlet, Portlet, PortletConfig, ResourceServingPortlet
public abstract class GenericPortlet
extends Object
implements Portlet, PortletConfig, EventPortlet, ResourceServingPortlet

The GenericPortlet class provides a default implementation for the Portlet interface.

It provides an abstract class to be subclassed to create portlets. A subclass of GenericPortlet should either use one of the following annotations:

or override at least one method, usually one of the following:

Normally there is no need to override the render or the doDispatch methods. Render handles render requests setting the title of the portlet in the response and invoking doDispatch. doDispatch dispatches the request to one of the doView, doEdit or doHelp method depending on the portlet mode indicated in the request.

Portlets typically run on multithreaded servers, so please note that a portlet must handle concurrent requests and be careful to synchronize access to shared resources. Shared resources include in-memory data such as instance or class variables and external objects such as files, database connections, and network connections.

Constructor Summary
GenericPortlet()
          Does nothing.

 

Method Summary
 void destroy()
          Called by the portlet container to indicate to a portlet that the portlet is being taken out of service.
protected  void doDispatch(RenderRequest request, RenderResponse response)
          The default implementation of this method routes the render request to: method annotated with @RenderMode</name> and the name of the portlet mode a set of helper methods depending on the current portlet mode the portlet is currently in.
protected  void doEdit(RenderRequest request, RenderResponse response)
          Helper method to serve up the edit mode.
protected  void doHeaders(RenderRequest request, RenderResponse response)
          Used by the render method to set the response properties and headers.
protected  void doHelp(RenderRequest request, RenderResponse response)
          Helper method to serve up the help mode.
protected  void doView(RenderRequest request, RenderResponse response)
          Helper method to serve up the mandatory view mode.
 Map<String,String[]> getContainerRuntimeOptions()
          Returns the container runtime options and values for this portlet.
 String getDefaultNamespace()
          Returns the default namespace for events and public parameters.
 String getInitParameter(String name)
          Returns a String containing the value of the named initialization * parameter, or null if the parameter does not exist.
 Enumeration<String> getInitParameterNames()
          Returns the names of the portlet initialization parameters as an Enumeration of String objects, or an empty Enumeration if the portlet has no initialization parameters.
protected  Collection<PortletMode> getNextPossiblePortletModes(RenderRequest request)
          Used by the render method to set the next possible portlet modes.
 PortletConfig getPortletConfig()
          Returns the PortletConfig object of this portlet.
 PortletContext getPortletContext()
          Returns the PortletContext of the portlet application the portlet is in.
 String getPortletName()
          Returns the name of this portlet.
 Enumeration<QName> getProcessingEventQNames()
          Returns the QNames of the processing events supported by the portlet as an Enumeration of QName objects, or an empty Enumeration if the portlet has not defined any processing events.
 Enumeration<String> getPublicRenderParameterNames()
          Returns the names of the public render parameters supported by the portlet as an Enumeration of String objects, or an empty Enumeration if the portlet has no public render parameters.
 Enumeration<QName> getPublishingEventQNames()
          Returns the QNames of the publishing events supported by the portlet as an Enumeration of QName objects, or an empty Enumeration if the portlet has not defined any publishing events.
 ResourceBundle getResourceBundle(Locale locale)
          Gets the resource bundle for the given locale based on the resource bundle defined in the deployment descriptor with resource-bundle tag or the inlined resources defined in the deployment descriptor.
 Enumeration<Locale> getSupportedLocales()
          Returns the locales supported by the portlet as an Enumeration of Locale objects, or an empty Enumeration if the portlet has not defined any supported locales.
protected  String getTitle(RenderRequest request)
          Used by the render method to get the title.
 void init()
          A convenience method which can be overridden so that there's no need to call super.init(config).
 void init(PortletConfig config)
          Called by the portlet container to indicate to a portlet that the portlet is being placed into service.
 void processAction(ActionRequest request, ActionResponse response)
          Called by the portlet container to allow the portlet to process an action request.
 void processEvent(EventRequest request, EventResponse response)
          The default implementation tries to dispatch to a method annotated with @ProcessEvent</name> that matches the event name or, if no such method is found just sets the current render parameters on the response.
Note that the annotated methods needs to be public in order to be allowed to be called by GenericPortlet.
 void render(RenderRequest request, RenderResponse response)
          The default implementation of this method sets the headers using the doHeaders method, sets the title using the getTitle method and invokes the doDispatch method.
 void serveResource(ResourceRequest request, ResourceResponse response)
          Default resource serving.

 

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

 

Constructor Detail

GenericPortlet

public GenericPortlet()
Does nothing.

Method Detail

init

public void init(PortletConfig config)
          throws PortletException
Called by the portlet container to indicate to a portlet that the portlet is being placed into service.

The default implementation stores the PortletConfig object and checks for annotated methods with the annotations

and stores these in a hashmap for later dispatching.

The portlet container calls the init method exactly once after instantiating the portlet. The init method must complete successfully before the portlet can receive any requests.

The portlet container cannot place the portlet into service if the init method does one of the following:

  1. it throws a PortletException
  2. it does not return within a time period defined by the Web server
Specified by:
init in interface Portlet
Parameters
config - a PortletConfig object containing the portlet configuration and initialization parameters
Throws
PortletException - if an exception has occurred that interferes with the portlet normal operation.
UnavailableException - if the portlet cannot perform the initialization at this time.

init

public void init()
          throws PortletException
A convenience method which can be overridden so that there's no need to call super.init(config).

Instead of overriding init(PortletConfig), simply override this method and it will be called by GenericPortlet.init(PortletConfig config). The PortletConfig object can still be retrieved via getPortletConfig().

Throws
PortletException - if an exception has occurred that interferes with the portlet normal operation.
UnavailableException - if the portlet is unavailable to perform init

processAction

public void processAction(ActionRequest request,
                          ActionResponse response)
                   throws PortletException,
                          IOException
Called by the portlet container to allow the portlet to process an action request. This method is called if the client request was originated by a URL created (by the portlet) with the RenderResponse.createActionURL() method.

The default implementation tries to dispatch to a method annotated with @ProcessAction</name> that matches the action parameter value ActionRequest.ACTION_NAME or, if no such method is found throws a PortletException.
Note that the annotated methods needs to be public in order to be allowed to be called by GenericPortlet.

Specified by:
processAction in interface Portlet
Parameters
request - the action request
response - the action response
Throws
PortletException - if the portlet cannot fulfilling the request
UnavailableException - if the portlet is unavailable to process the action at this time
PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
IOException - if the streaming causes an I/O problem

render

public void render(RenderRequest request,
                   RenderResponse response)
            throws PortletException,
                   IOException
The default implementation of this method sets the headers using the doHeaders method, sets the title using the getTitle method and invokes the doDispatch method.

It also evaluates the RENDER_PART request attribute and if set calls the doHeaders, getNextPossiblePortletModes and getTitle methods for the RENDER_HEADERS part and the doDispatch method for the RENDER_MARKUP part.
If the RENDER_PART request attribute is not set all of the above methods will be called.

Specified by:
render in interface Portlet
Parameters
request - the render request
response - the render response
Throws
PortletException - if the portlet cannot fulfilling the request
UnavailableException - if the portlet is unavailable to perform render at this time
PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
IOException - if the streaming causes an I/O problem

getTitle

protected String getTitle(RenderRequest request)
Used by the render method to get the title.

The default implementation gets the title from the ResourceBundle of the PortletConfig of the portlet. The title is retrieved using the 'javax.portlet.title' resource name.

Portlets can overwrite this method to provide dynamic titles (e.g. based on locale, client, and session information). Examples are:

Returns
the portlet title for this window
Throws
IllegalStateException - if no portlet config object is available

doDispatch

protected void doDispatch(RenderRequest request,
                          RenderResponse response)
                   throws PortletException,
                          IOException
The default implementation of this method routes the render request to:
  1. method annotated with @RenderMode</name> and the name of the portlet mode
  2. a set of helper methods depending on the current portlet mode the portlet is currently in. These methods are:
    • doView for handling view requests
    • doEdit for handling edit requests
    • doHelp for handling help requests

  3. If the window state of this portlet is minimized, this method does not invoke any of the portlet mode rendering methods.

    For handling custom portlet modes the portlet should either use the @RenderMode annotation or override this method. Note that the annotated methods needs to be public in order to be allowed to be called by GenericPortlet.

    Parameters
    request - the render request
    response - the render response
    Throws
    PortletException - if the portlet cannot fulfilling the request
    UnavailableException - if the portlet is unavailable to perform render at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem
    See Also
    doView(RenderRequest, RenderResponse), doEdit(RenderRequest, RenderResponse), doHelp(RenderRequest, RenderResponse)

    doView

    protected void doView(RenderRequest request,
                      RenderResponse response)
               throws PortletException,
                      IOException
    Helper method to serve up the mandatory view mode.

    The default implementation throws an exception.

    Parameters
    request - the portlet request
    response - the render response
    Throws
    PortletException - if the portlet cannot fulfilling the request
    UnavailableException - if the portlet is unavailable to perform render at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem

    doEdit

    protected void doEdit(RenderRequest request,
                      RenderResponse response)
               throws PortletException,
                      IOException
    Helper method to serve up the edit mode.

    The default implementation throws an exception.

    Parameters
    request - the portlet request
    response - the render response
    Throws
    PortletException - if the portlet cannot fulfilling the request
    UnavailableException - if the portlet is unavailable to perform render at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem

    doHelp

    protected void doHelp(RenderRequest request,
                      RenderResponse response)
               throws PortletException,
                      IOException
    Helper method to serve up the help mode.

    The default implementation throws an exception.

    Parameters
    request - the portlet request
    response - the render response
    Throws
    PortletException - if the portlet cannot fulfilling the request
    UnavailableException - if the portlet is unavailable to perform render at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem

    getPortletConfig

    public PortletConfig getPortletConfig()
    Returns the PortletConfig object of this portlet.
    Returns
    the PortletConfig object of this portlet

    destroy

    public void destroy()
    Called by the portlet container to indicate to a portlet that the portlet is being taken out of service.

    The default implementation does nothing.

    Specified by:
    destroy in interface Portlet

    getPortletName

    public String getPortletName()
    Returns the name of this portlet.
    Specified by:
    getPortletName in interface PortletConfig
    Returns
    the portlet name
    See Also
    PortletConfig.getPortletName()

    getPortletContext

    public PortletContext getPortletContext()
    Returns the PortletContext of the portlet application the portlet is in.
    Specified by:
    getPortletContext in interface PortletConfig
    Returns
    the portlet application context
    See Also
    PortletContext

    getResourceBundle

    public ResourceBundle getResourceBundle(Locale locale)
    Gets the resource bundle for the given locale based on the resource bundle defined in the deployment descriptor with resource-bundle tag or the inlined resources defined in the deployment descriptor.
    Specified by:
    getResourceBundle in interface PortletConfig
    Parameters
    locale - the locale for which to retrieve the resource bundle
    Returns
    the resource bundle for the given locale

    getInitParameter

    public String getInitParameter(String name)
    Returns a String containing the value of the named initialization * parameter, or null if the parameter does not exist.
    Specified by:
    getInitParameter in interface PortletConfig
    Parameters
    name - a String specifying the name of the initialization parameter
    Returns
    a String containing the value of the initialization parameter
    Throws
    IllegalArgumentException - if name is null.

    getInitParameterNames

    public Enumeration<String> getInitParameterNames()
    Returns the names of the portlet initialization parameters as an Enumeration of String objects, or an empty Enumeration if the portlet has no initialization parameters.
    Specified by:
    getInitParameterNames in interface PortletConfig
    Returns
    an Enumeration of String objects containing the names of the portlet initialization parameters, or an empty Enumeration if the portlet has no initialization parameters.

    getProcessingEventQNames

    public Enumeration<QName> getProcessingEventQNames()
    Description copied from interface: PortletConfig
    Returns the QNames of the processing events supported by the portlet as an Enumeration of QName objects, or an empty Enumeration if the portlet has not defined any processing events.

    Processing events are defined in the portlet deployment descriptor with the supported-processing-event element.

    If the event was defined using the name element instead of the qname element the defined default namespace is added as namespace for the returned QName.

    Specified by:
    getProcessingEventQNames in interface PortletConfig
    Returns
    an Enumeration of QName objects containing the names of the processing events, or an empty Enumeration if the portlet has not defined any support for processing events in the deployment descriptor.

    getPublishingEventQNames

    public Enumeration<QName> getPublishingEventQNames()
    Description copied from interface: PortletConfig
    Returns the QNames of the publishing events supported by the portlet as an Enumeration of QName objects, or an empty Enumeration if the portlet has not defined any publishing events.

    Publishing events are defined in the portlet deployment descriptor with the supported-publishing-event element.

    Note that this call does not return any events published that have not been declared in the deployment descriptor as supported.

    If the event was defined using the name element instead of the qname element the defined default namespace is added as namespace for the returned QName.

    Specified by:
    getPublishingEventQNames in interface PortletConfig
    Returns
    an Enumeration of QName objects containing the names of the publishing events, or an empty Enumeration if the portlet has not defined any support for publishing events in the deployment descriptor.

    getSupportedLocales

    public Enumeration<Locale> getSupportedLocales()
    Description copied from interface: PortletConfig
    Returns the locales supported by the portlet as an Enumeration of Locale objects, or an empty Enumeration if the portlet has not defined any supported locales.

    Supported locales are defined in the portlet deployment descriptor with the supported-locale element.

    Specified by:
    getSupportedLocales in interface PortletConfig
    Returns
    an Enumeration of Locale objects containing the supported locales, or an empty Enumeration if the portlet has not defined any supported locales in the deployment descriptor.

    getContainerRuntimeOptions

    public Map<String,String[]> getContainerRuntimeOptions()
    Description copied from interface: PortletConfig
    Returns the container runtime options and values for this portlet.

    The portlet can set container runtime options in the portlet.xml via the container-runtime-option element with a name and a value on the application and portlet level.
    If a container runtime option is set on the portlet application level and on the portlet level with the same name the setting on the portlet level takes precedence and overwrites the one set on the portal application level.

    The map returned from this method will provide the subset the portlet container supports of the options the portlet has specified in the portlet.xml. Options that the portlet container does not support will not be returned in this map.

    The map will contain name of the runtime option as key of type String and the runtime options as values of type String array (String[]) with the values specified in the portlet.xml deployment descriptor.

    Specified by:
    getContainerRuntimeOptions in interface PortletConfig
    Returns
    an immutable Map containing portlet container runtime options names as keys and the container runtime values as map values, or an empty Map if no portlet container runtime options are set in the portlet.xml or supported by this portlet container. The keys in the map are of type String. The values in the map are of type String array (String[]).

    serveResource

    public void serveResource(ResourceRequest request,
                          ResourceResponse response)
                   throws PortletException,
                          IOException
    Default resource serving.

    The default implemention of this method is to call a RequestDispatcher.foward with the ResourceID of the ResourceRequest.

    If no ResourceID is set on the resource URL the default implementation does nothing.

    Specified by:
    serveResource in interface ResourceServingPortlet
    Parameters
    request - the resource request
    response - the resource response
    Throws
    PortletException - if the portlet has problems fulfilling the rendering request
    UnavailableException - if the portlet is unavailable to perform render at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem
    Since:
    2.0

    processEvent

    public void processEvent(EventRequest request,
                         EventResponse response)
                  throws PortletException,
                         IOException
    The default implementation tries to dispatch to a method annotated with @ProcessEvent</name> that matches the event name or, if no such method is found just sets the current render parameters on the response.
    Note that the annotated methods needs to be public in order to be allowed to be called by     GenericPortlet.
    Specified by:
    processEvent in interface EventPortlet
    Parameters
    request - the event request
    response - the event response
    Throws
    PortletException - if the portlet has problems fulfilling the request
    UnavailableException - if the portlet is unavailable to process the event at this time
    PortletSecurityException - if the portlet cannot fullfill this request because of security reasons
    IOException - if the streaming causes an I/O problem
    Since:
    2.0
    See Also
    EventPortlet.processEvent(javax.portlet.EventRequest, javax.portlet.EventResponse)

    doHeaders

    protected void doHeaders(RenderRequest request,
                         RenderResponse response)
    Used by the render method to set the response properties and headers.

    The portlet should override this method and set its response header using this method in order to ensure that they are set before anything is written to the output stream.

    The default implemention of this method is emtpy.

    Parameters
    request - the render request
    response - the render response
    Since:
    2.0

    getNextPossiblePortletModes

    protected Collection<PortletMode> getNextPossiblePortletModes(RenderRequest request)
    Used by the render method to set the next possible portlet modes.

    The portlet should override this method and set the next possible portlet modes using this method in order to ensure that they are set before anything is written to the output stream.

    The default implemention of this method returns null.

    Since:
    2.0

    getPublicRenderParameterNames

    public Enumeration<String> getPublicRenderParameterNames()
    Returns the names of the public render parameters supported by the portlet as an Enumeration of String objects, or an empty Enumeration if the portlet has no public render parameters.
    Specified by:
    getPublicRenderParameterNames in interface PortletConfig
    Returns
    an Enumeration of String objects containing the names of the public render parameters, or an empty Enumeration if the portlet does not define any public render parameters.
    See Also
    PortletConfig.getPublicRenderParameterNames()

    getDefaultNamespace

    public String getDefaultNamespace()
    Returns the default namespace for events and public parameters. This namespace is defined in the portlet deployment descriptor with the default-namespace element.

    If no default namespace is defined in the portlet deployment descriptor this methods returns the XML default namespace XMLConstants.NULL_NS_URI.

    Specified by:
    getDefaultNamespace in interface PortletConfig
    Returns
    the default namespace defined in the portlet deployment descriptor, or XMLConstants.NULL_NS_URI is non is defined.
    See Also
    PortletConfig.getDefaultNamespace()
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