org.apache.struts.action

Class Action

public class Action extends Object

An Action is an adapter between the contents of an incoming HTTP request and the corresponding business logic that should be executed to process this request. The controller (RequestProcessor) will select an appropriate Action for each request, create an instance (if necessary), and call the execute method.

Actions must be programmed in a thread-safe manner, because the controller will share the same instance for multiple simultaneous requests. This means you should design with the following items in mind:

When an Action instance is first created, the controller will call setServlet with a non-null argument to identify the servlet instance to which this Action is attached. When the servlet is to be shut down (or restarted), the setServlet method will be called with a null argument, which can be used to clean up any allocated resources in use by this Action.

Version: $Rev: 164530 $ $Date: 2005-04-25 04:11:07 +0100 (Mon, 25 Apr 2005) $

Field Summary
protected static LocaledefaultLocale

The system default Locale.

protected ActionServletservlet

The servlet to which we are attached.

static TokenProcessortoken

An instance of TokenProcessor to use for token functionality.

Method Summary
protected voidaddErrors(HttpServletRequest request, ActionMessages errors)
Adds the specified errors keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required.
protected voidaddMessages(HttpServletRequest request, ActionMessages messages)
Adds the specified messages keys into the appropriate request attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required.
ActionForwardexecute(ActionMapping mapping, ActionForm form, ServletRequest request, ServletResponse response)

Process the specified non-HTTP request, and create the corresponding non-HTTP response (or forward to another web component that will create it), with provision for handling exceptions thrown by the business logic.

ActionForwardexecute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)

Process the specified HTTP request, and create the corresponding HTTP response (or forward to another web component that will create it), with provision for handling exceptions thrown by the business logic.

protected StringgenerateToken(HttpServletRequest request)

Generate a new transaction token, to be used for enforcing a single request for a particular transaction.

protected DataSourcegetDataSource(HttpServletRequest request)

Return the default data source for the current module.

protected DataSourcegetDataSource(HttpServletRequest request, String key)

Return the specified data source for the current module.

protected ActionMessagesgetErrors(HttpServletRequest request)
Retrieves any existing errors placed in the request by previous actions.
protected LocalegetLocale(HttpServletRequest request)

Return the user's currently selected Locale.

protected ActionMessagesgetMessages(HttpServletRequest request)
Retrieves any existing messages placed in the request by previous actions.
protected MessageResourcesgetResources(HttpServletRequest request)

Return the default message resources for the current module.

protected MessageResourcesgetResources(HttpServletRequest request, String key)

Return the specified message resources for the current module.

ActionServletgetServlet()

Return the servlet instance to which we are attached.

protected booleanisCancelled(HttpServletRequest request)

Returns true if the current form's cancel button was pressed.

protected booleanisTokenValid(HttpServletRequest request)

Return true if there is a transaction token stored in the user's current session, and the value submitted as a request parameter with this action matches it.

protected booleanisTokenValid(HttpServletRequest request, boolean reset)

Return true if there is a transaction token stored in the user's current session, and the value submitted as a request parameter with this action matches it.

protected voidresetToken(HttpServletRequest request)

Reset the saved transaction token in the user's session.

protected voidsaveErrors(HttpServletRequest request, ActionErrors errors)

Save the specified error messages keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required.

protected voidsaveErrors(HttpServletRequest request, ActionMessages errors)

Save the specified error messages keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required.

protected voidsaveErrors(HttpSession session, ActionMessages errors)

Save the specified error messages keys into the appropriate session attribute for use by the <html:messages> tag (if messages="false") or <html:errors>, if any error messages are required.

protected voidsaveMessages(HttpServletRequest request, ActionMessages messages)

Save the specified messages keys into the appropriate request attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required.

protected voidsaveMessages(HttpSession session, ActionMessages messages)

Save the specified messages keys into the appropriate session attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required.

protected voidsaveToken(HttpServletRequest request)

Save a new transaction token in the user's current session, creating a new session if necessary.

protected voidsetLocale(HttpServletRequest request, Locale locale)

Set the user's currently selected Locale into their HttpSession.

voidsetServlet(ActionServlet servlet)

Set the servlet instance to which we are attached (if servlet is non-null), or release any allocated resources (if servlet is null).

Field Detail

defaultLocale

protected static Locale defaultLocale

Deprecated: Use Locale.getDefault directly. This will be removed after Struts 1.2.

The system default Locale.

servlet

protected ActionServlet servlet

The servlet to which we are attached.

token

private static TokenProcessor token

An instance of TokenProcessor to use for token functionality.

Method Detail

addErrors

protected void addErrors(HttpServletRequest request, ActionMessages errors)
Adds the specified errors keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required. Initialize the attribute if it has not already been. Otherwise, ensure that the request attribute is not set.

Parameters: request The servlet request we are processing errors Errors object

Since: Struts 1.2.1

addMessages

protected void addMessages(HttpServletRequest request, ActionMessages messages)
Adds the specified messages keys into the appropriate request attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required. Initialize the attribute if it has not already been. Otherwise, ensure that the request attribute is not set.

Parameters: request The servlet request we are processing messages Messages object

Since: Struts 1.2.1

execute

public ActionForward execute(ActionMapping mapping, ActionForm form, ServletRequest request, ServletResponse response)

Process the specified non-HTTP request, and create the corresponding non-HTTP response (or forward to another web component that will create it), with provision for handling exceptions thrown by the business logic. Return an {@link ActionForward} instance describing where and how control should be forwarded, or null if the response has already been completed.

The default implementation attempts to forward to the HTTP version of this method.

Parameters: mapping The ActionMapping used to select this instance form The optional ActionForm bean for this request (if any) request The non-HTTP request we are processing response The non-HTTP response we are creating

Throws: Exception if the application business logic throws an exception.

Since: Struts 1.1

execute

public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)

Process the specified HTTP request, and create the corresponding HTTP response (or forward to another web component that will create it), with provision for handling exceptions thrown by the business logic. Return an {@link ActionForward} instance describing where and how control should be forwarded, or null if the response has already been completed.

Parameters: mapping The ActionMapping used to select this instance form The optional ActionForm bean for this request (if any) request The HTTP request we are processing response The HTTP response we are creating

Throws: Exception if the application business logic throws an exception

Since: Struts 1.1

generateToken

protected String generateToken(HttpServletRequest request)

Generate a new transaction token, to be used for enforcing a single request for a particular transaction.

Parameters: request The request we are processing

getDataSource

protected DataSource getDataSource(HttpServletRequest request)

Return the default data source for the current module.

Parameters: request The servlet request we are processing

Since: Struts 1.1

getDataSource

protected DataSource getDataSource(HttpServletRequest request, String key)

Return the specified data source for the current module.

Parameters: request The servlet request we are processing key The key specified in the <data-sources> element.

Since: Struts 1.1

getErrors

protected ActionMessages getErrors(HttpServletRequest request)
Retrieves any existing errors placed in the request by previous actions. This method could be called instead of creating a new ActionMessages() at the beginning of an Action This will prevent saveErrors() from wiping out any existing Errors

Parameters: request The servlet request we are processing

Returns: the Errors that already exist in the request, or a new ActionMessages object if empty.

Since: Struts 1.2.1

getLocale

protected Locale getLocale(HttpServletRequest request)

Return the user's currently selected Locale.

Parameters: request The request we are processing

getMessages

protected ActionMessages getMessages(HttpServletRequest request)
Retrieves any existing messages placed in the request by previous actions. This method could be called instead of creating a new ActionMessages() at the beginning of an Action This will prevent saveMessages() from wiping out any existing Messages

Parameters: request The servlet request we are processing

Returns: the Messages that already exist in the request, or a new ActionMessages object if empty.

Since: Struts 1.2.1

getResources

protected MessageResources getResources(HttpServletRequest request)

Return the default message resources for the current module.

Parameters: request The servlet request we are processing

Since: Struts 1.1

getResources

protected MessageResources getResources(HttpServletRequest request, String key)

Return the specified message resources for the current module.

Parameters: request The servlet request we are processing key The key specified in the <message-resources> element for the requested bundle

Since: Struts 1.1

getServlet

public ActionServlet getServlet()

Return the servlet instance to which we are attached.

isCancelled

protected boolean isCancelled(HttpServletRequest request)

Returns true if the current form's cancel button was pressed. This method will check if the Globals.CANCEL_KEY request attribute has been set, which normally occurs if the cancel button generated by CancelTag was pressed by the user in the current request. If true, validation performed by an ActionForm's validate() method will have been skipped by the controller servlet.

Parameters: request The servlet request we are processing

See Also: CancelTag

isTokenValid

protected boolean isTokenValid(HttpServletRequest request)

Return true if there is a transaction token stored in the user's current session, and the value submitted as a request parameter with this action matches it. Returns false under any of the following circumstances:

  • No session associated with this request
  • No transaction token saved in the session
  • No transaction token included as a request parameter
  • The included transaction token value does not match the transaction token in the user's session

Parameters: request The servlet request we are processing

isTokenValid

protected boolean isTokenValid(HttpServletRequest request, boolean reset)

Return true if there is a transaction token stored in the user's current session, and the value submitted as a request parameter with this action matches it. Returns false under any of the following circumstances:

  • No session associated with this request
  • No transaction token saved in the session
  • No transaction token included as a request parameter
  • The included transaction token value does not match the transaction token in the user's session

Parameters: request The servlet request we are processing reset Should we reset the token after checking it?

resetToken

protected void resetToken(HttpServletRequest request)

Reset the saved transaction token in the user's session. This indicates that transactional token checking will not be needed on the next request that is submitted.

Parameters: request The servlet request we are processing

saveErrors

protected void saveErrors(HttpServletRequest request, ActionErrors errors)

Deprecated: Use saveErrors(HttpServletRequest, ActionMessages) instead. This will be removed after Struts 1.2.

Save the specified error messages keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required. Otherwise, ensure that the request attribute is not created.

Parameters: request The servlet request we are processing errors Error messages object

saveErrors

protected void saveErrors(HttpServletRequest request, ActionMessages errors)

Save the specified error messages keys into the appropriate request attribute for use by the <html:errors> tag, if any messages are required. Otherwise, ensure that the request attribute is not created.

Parameters: request The servlet request we are processing errors Error messages object

Since: Struts 1.2

saveErrors

protected void saveErrors(HttpSession session, ActionMessages errors)

Save the specified error messages keys into the appropriate session attribute for use by the <html:messages> tag (if messages="false") or <html:errors>, if any error messages are required. Otherwise, ensure that the session attribute is empty.

Parameters: session The session to save the error messages in. errors The error messages to save. null or empty messages removes any existing error ActionMessages in the session.

Since: Struts 1.2.7

saveMessages

protected void saveMessages(HttpServletRequest request, ActionMessages messages)

Save the specified messages keys into the appropriate request attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required. Otherwise, ensure that the request attribute is not created.

Parameters: request The servlet request we are processing. messages The messages to save. null or empty messages removes any existing ActionMessages in the request.

Since: Struts 1.1

saveMessages

protected void saveMessages(HttpSession session, ActionMessages messages)

Save the specified messages keys into the appropriate session attribute for use by the <html:messages> tag (if messages="true" is set), if any messages are required. Otherwise, ensure that the session attribute is not created.

Parameters: session The session to save the messages in. messages The messages to save. null or empty messages removes any existing ActionMessages in the session.

Since: Struts 1.2

saveToken

protected void saveToken(HttpServletRequest request)

Save a new transaction token in the user's current session, creating a new session if necessary.

Parameters: request The servlet request we are processing

setLocale

protected void setLocale(HttpServletRequest request, Locale locale)

Set the user's currently selected Locale into their HttpSession.

Parameters: request The request we are processing locale The user's selected Locale to be set, or null to select the server's default Locale

setServlet

public void setServlet(ActionServlet servlet)

Set the servlet instance to which we are attached (if servlet is non-null), or release any allocated resources (if servlet is null).

Parameters: servlet The new controller servlet, if any

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