com.interface21.web.servlet.view
Class AbstractCachingViewResolver

java.lang.Object
  |
  +--com.interface21.context.support.ApplicationObjectSupport
        |
        +--com.interface21.web.servlet.view.AbstractCachingViewResolver

All Implemented Interfaces:

ApplicationContextAware, ViewResolver

Direct Known Subclasses:

InternalResourceViewResolver, ResourceBundleViewResolver, XmlViewResolver

public abstract class AbstractCachingViewResolver

extends ApplicationObjectSupport

implements ViewResolver

Convenient superclass for view resolvers. Caches views once resolved. This means that view resolution won't be a performance problem, no matter how costly initial view retrieval is. View retrieval is deferred to subclasses.

Author:

Rod Johnson

Fields inherited from class com.interface21.context.support.ApplicationObjectSupport

logger

Constructor Summary

AbstractCachingViewResolver()

Method Summary

boolean	isCache() If caching is enabled.
protected abstract View	loadView(java.lang.String viewName, java.util.Locale locale) Subclasses must implement this method.
View	resolveViewName(java.lang.String viewName, java.util.Locale locale) Resolve the given view by name.
void	setCache(boolean cache) Enable caching.

Methods inherited from class com.interface21.context.support.ApplicationObjectSupport

getApplicationContext, initApplicationContext, setApplicationContext

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.interface21.context.ApplicationContextAware

setApplicationContext

Constructor Detail

AbstractCachingViewResolver

public AbstractCachingViewResolver()

Method Detail

setCache

public void setCache(boolean cache)

Enable caching. Disable this only for debugging and development. Default is for caching to be enabled.

Warning: disabling caching severely impacts performance. Tests indicate that turning caching off reduces performance by at least 20%. Increased object churn probably eventually makes the problem even worse.

isCache

public boolean isCache()

If caching is enabled.

resolveViewName

public final View resolveViewName(java.lang.String viewName,
                                  java.util.Locale locale)
                           throws javax.servlet.ServletException

Description copied from interface: ViewResolver

Resolve the given view by name.

Specified by:

resolveViewName in interface ViewResolver

Following copied from interface: com.interface21.web.servlet.ViewResolver

Parameters:

viewName - name of the view to resolve

locale - Locale in which to resolve the view. ViewResolvers that support internationalization should respect this.

Throws:

javax.servlet.ServletException - if the view cannot be resolved.

loadView

protected abstract View loadView(java.lang.String viewName,
                                 java.util.Locale locale)
                          throws javax.servlet.ServletException

Subclasses must implement this method. There need be no concern for efficiency, as this class will cache views. Not all subclasses may support internationalization: A subclass that doesn't can ignore the locale parameter.

Parameters:

viewName - name of the view to retrieve

locale - Locale to retrieve the view for

Returns:

the View if it can be resolved, or null

Throws:

javax.servlet.ServletException - if there is an error trying to resolve the view