de.neteye.actioncache
Class AbstractCacheableAction

java.lang.Object
  |
  +--org.apache.struts.action.Action
        |
        +--de.neteye.actioncache.AbstractCacheableAction

All Implemented Interfaces:

CacheableAction

Direct Known Subclasses:

ExampleAction

public abstract class AbstractCacheableAction

extends org.apache.struts.action.Action

implements CacheableAction

Abstract class that implements time based expiration. Subclasses can overide the getTimeToLive() method to return the number of milliseconds that must elapse before getLastModified is called again.

Version:

$Revision: 1.3 $

Author:

Felix Gnass

Field Summary

protected static int

DEFAULT_TTL

Fields inherited from class org.apache.struts.action.Action

ACTION_SERVLET_KEY, APPLICATION_KEY, DATA_SOURCE_KEY, defaultLocale, ERROR_KEY, EXCEPTION_KEY, FORM_BEANS_KEY, FORWARDS_KEY, LOCALE_KEY, MAPPING_KEY, MAPPINGS_KEY, MESSAGE_KEY, MESSAGES_KEY, MULTIPART_KEY, PLUG_INS_KEY, REQUEST_PROCESSOR_KEY, servlet, SERVLET_KEY, TRANSACTION_TOKEN_KEY

Constructor Summary

AbstractCacheableAction()

Method Summary

abstract org.apache.struts.action.ActionForward	execute(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
java.lang.String	getCacheKey(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Returns the action's class name by default.
long	getLastModified(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) The default implementation returns System.currentTimeMillis() so that the item is refreshed as soon as it expires.
long	getLastModified(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, ActionCacheItem cacheItem) First checks if given CacheItem is older than the time to live.
int	getTimeToLive(org.apache.struts.action.ActionMapping mapping, org.apache.struts.action.ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Returns 5000 as default.

Methods inherited from class org.apache.struts.action.Action

execute, generateToken, getDataSource, getDataSource, getLocale, getResources, getResources, getResources, getServlet, isCancelled, isTokenValid, isTokenValid, perform, perform, resetToken, saveErrors, saveMessages, saveToken, setLocale, setServlet, toHex

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_TTL

protected static final int DEFAULT_TTL

See Also:

Constant Field Values

Constructor Detail

AbstractCacheableAction

public AbstractCacheableAction()

Method Detail

getCacheKey

public java.lang.String getCacheKey(org.apache.struts.action.ActionMapping mapping,
                                    org.apache.struts.action.ActionForm form,
                                    javax.servlet.http.HttpServletRequest request,
                                    javax.servlet.http.HttpServletResponse response)

Returns the action's class name by default. Subclasses that react on parameters must include these in the returned key.

Specified by:

getCacheKey in interface CacheableAction

getLastModified

public final long getLastModified(org.apache.struts.action.ActionMapping mapping,
                                  org.apache.struts.action.ActionForm form,
                                  javax.servlet.http.HttpServletRequest request,
                                  javax.servlet.http.HttpServletResponse response,
                                  ActionCacheItem cacheItem)
                           throws java.io.IOException,
                                  javax.servlet.ServletException

First checks if given CacheItem is older than the time to live. If it has expired, the abstract getLastModified() method is called. In case the actual modification time is not newer than cached item, the item is "touched" and will live for another timeToLive milliseconds.

Specified by:

getLastModified in interface CacheableAction

java.io.IOException

javax.servlet.ServletException

getLastModified

public long getLastModified(org.apache.struts.action.ActionMapping mapping,
                            org.apache.struts.action.ActionForm form,
                            javax.servlet.http.HttpServletRequest request,
                            javax.servlet.http.HttpServletResponse response)
                     throws java.io.IOException,
                            javax.servlet.ServletException

The default implementation returns System.currentTimeMillis() so that the item is refreshed as soon as it expires. Subclasses should override this method to return something reasonable.

java.io.IOException

javax.servlet.ServletException

getTimeToLive

public int getTimeToLive(org.apache.struts.action.ActionMapping mapping,
                         org.apache.struts.action.ActionForm form,
                         javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response)

Returns 5000 as default.

execute

public abstract org.apache.struts.action.ActionForward execute(org.apache.struts.action.ActionMapping mapping,
                                                               org.apache.struts.action.ActionForm form,
                                                               javax.servlet.http.HttpServletRequest request,
                                                               javax.servlet.http.HttpServletResponse response)
                                                        throws java.io.IOException,
                                                               javax.servlet.ServletException

Overrides:

execute in class org.apache.struts.action.Action

java.io.IOException

javax.servlet.ServletException