org.apache.struts.action
Class Action

java.lang.Object
  |
  +--org.apache.struts.action.Action
Direct Known Subclasses:
DefinitionDispatcherAction, DispatchAction, DownloadAction, ForwardAction, IncludeAction, LocaleAction, ReloadDefinitionsAction, SwitchAction, TilesAction, ViewDefinitionsAction

public class Action
extends java.lang.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 java.util.Locale defaultLocale
          Deprecated. Use Locale.getDefault directly. This will be removed after Struts 1.2.
protected  ActionServlet servlet
          The servlet to which we are attached.
private static TokenProcessor token
          An instance of TokenProcessor to use for token functionality.
 
Constructor Summary
Action()
           
 
Method Summary
protected  void addErrors(javax.servlet.http.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  void addMessages(javax.servlet.http.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.
 ActionForward execute(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.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.
 ActionForward execute(ActionMapping mapping, ActionForm form, javax.servlet.ServletRequest request, javax.servlet.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.
protected  java.lang.String generateToken(javax.servlet.http.HttpServletRequest request)
          Generate a new transaction token, to be used for enforcing a single request for a particular transaction.
protected  javax.sql.DataSource getDataSource(javax.servlet.http.HttpServletRequest request)
          Return the default data source for the current module.
protected  javax.sql.DataSource getDataSource(javax.servlet.http.HttpServletRequest request, java.lang.String key)
          Return the specified data source for the current module.
protected  ActionMessages getErrors(javax.servlet.http.HttpServletRequest request)
          Retrieves any existing errors placed in the request by previous actions.
protected  java.util.Locale getLocale(javax.servlet.http.HttpServletRequest request)
          Return the user's currently selected Locale.
protected  ActionMessages getMessages(javax.servlet.http.HttpServletRequest request)
          Retrieves any existing messages placed in the request by previous actions.
protected  MessageResources getResources(javax.servlet.http.HttpServletRequest request)
          Return the default message resources for the current module.
protected  MessageResources getResources(javax.servlet.http.HttpServletRequest request, java.lang.String key)
          Return the specified message resources for the current module.
 ActionServlet getServlet()
          Return the servlet instance to which we are attached.
protected  boolean isCancelled(javax.servlet.http.HttpServletRequest request)
          Returns true if the current form's cancel button was pressed.
protected  boolean isTokenValid(javax.servlet.http.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  boolean isTokenValid(javax.servlet.http.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  void resetToken(javax.servlet.http.HttpServletRequest request)
          Reset the saved transaction token in the user's session.
protected  void saveErrors(javax.servlet.http.HttpServletRequest request, ActionErrors errors)
          Deprecated. Use saveErrors(HttpServletRequest, ActionMessages) instead. This will be removed after Struts 1.2.
protected  void saveErrors(javax.servlet.http.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  void saveErrors(javax.servlet.http.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  void saveMessages(javax.servlet.http.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  void saveMessages(javax.servlet.http.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  void saveToken(javax.servlet.http.HttpServletRequest request)
          Save a new transaction token in the user's current session, creating a new session if necessary.
protected  void setLocale(javax.servlet.http.HttpServletRequest request, java.util.Locale locale)
          Set the user's currently selected Locale into their HttpSession.
 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).
 
Methods inherited from class java.lang.Object
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait
 

Field Detail

token

private static TokenProcessor token

An instance of TokenProcessor to use for token functionality.


defaultLocale

protected static java.util.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.

Constructor Detail

Action

public Action()
Method Detail

getServlet

public ActionServlet getServlet()

Return the servlet instance to which we are attached.


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

execute

public ActionForward execute(ActionMapping mapping,
                             ActionForm form,
                             javax.servlet.ServletRequest request,
                             javax.servlet.ServletResponse response)
                      throws java.lang.Exception

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 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:
java.lang.Exception - if the application business logic throws an exception.
Since:
Struts 1.1

execute

public ActionForward execute(ActionMapping mapping,
                             ActionForm form,
                             javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.lang.Exception

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 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:
java.lang.Exception - if the application business logic throws an exception
Since:
Struts 1.1

addMessages

protected void addMessages(javax.servlet.http.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

addErrors

protected void addErrors(javax.servlet.http.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

generateToken

protected java.lang.String generateToken(javax.servlet.http.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 javax.sql.DataSource getDataSource(javax.servlet.http.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 javax.sql.DataSource getDataSource(javax.servlet.http.HttpServletRequest request,
                                             java.lang.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(javax.servlet.http.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 java.util.Locale getLocale(javax.servlet.http.HttpServletRequest request)

Return the user's currently selected Locale.

Parameters:
request - The request we are processing

getMessages

protected ActionMessages getMessages(javax.servlet.http.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(javax.servlet.http.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(javax.servlet.http.HttpServletRequest request,
                                        java.lang.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

isCancelled

protected boolean isCancelled(javax.servlet.http.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(javax.servlet.http.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(javax.servlet.http.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(javax.servlet.http.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(javax.servlet.http.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(javax.servlet.http.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

saveMessages

protected void saveMessages(javax.servlet.http.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(javax.servlet.http.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

saveErrors

protected void saveErrors(javax.servlet.http.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

saveToken

protected void saveToken(javax.servlet.http.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(javax.servlet.http.HttpServletRequest request,
                         java.util.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


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