Java Doc for Action.java in  » Web-Framework » struts-1.3.8 » org » apache » struts » action » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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:

• Instance and static variables MUST NOT be used to store information related to the state of a particular request. They MAY be used to share global resources across requests for the same action.
• Access to other resources (JavaBeans, session variables, etc.) MUST be synchronized if those resources require protection. (Generally, however, resource classes should be designed to provide their own protection where necessary.

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.

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.

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.

Retrieves any existing messages placed in the request by previous actions.

Return the specified message resources for the current module.

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

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.

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.

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

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

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.

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.

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.

The servlet to which we are attached.

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.

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.

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

Return the user's currently selected Locale.

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

Return the default message resources for the current module.

Return the specified message resources for the current module.

Return the servlet instance to which we are attached.

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.

Since Action 1.3.0, the mapping for a cancellable Action must also have the new "cancellable" property set to true. If "cancellable" is not set, and the magic Cancel token is found in the request, the standard Composable Request Processor will throw an InvalidCancelException.

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

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

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.

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.

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.

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.

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.

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

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

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