程序包 cn.taketoday.web.view

类 AbstractCachingViewResolver

java.lang.Object
cn.taketoday.context.support.ApplicationObjectSupport
cn.taketoday.web.view.AbstractCachingViewResolver
所有已实现的接口:
cn.taketoday.beans.factory.Aware, cn.taketoday.context.ApplicationContextAware, ViewResolver
直接已知子类:
UrlBasedViewResolver
public abstract class AbstractCachingViewResolver extends cn.taketoday.context.support.ApplicationObjectSupport implements ViewResolver
Convenient base class for ViewResolver implementations. Caches View objects once resolved: This means that view resolution won't be a performance problem, no matter how costly initial view retrieval is.

Subclasses need to implement the loadView(java.lang.String, java.util.Locale) template method, building the View object for a specific view name and locale.

作者:
Harry Yang, Rod Johnson, Juergen Hoeller
另请参阅:

  • 字段详细资料

    • DEFAULT_CACHE_LIMIT

      public static final int DEFAULT_CACHE_LIMIT
      Default maximum number of entries for the view cache: 1024.
      另请参阅:

    • UNRESOLVED_VIEW

      public static final View UNRESOLVED_VIEW
      Dummy marker object for unresolved views in the cache Maps.

    • DEFAULT_CACHE_FILTER

      public static final AbstractCachingViewResolver.CacheFilter DEFAULT_CACHE_FILTER
      Default cache filter that always caches.

    • cacheLimit

      private volatile int cacheLimit
      The maximum number of entries in the cache.

    • cacheUnresolved

      private boolean cacheUnresolved
      Whether we should refrain from resolving views again if unresolved once.

    • cacheFilter

      private AbstractCachingViewResolver.CacheFilter cacheFilter
      Filter function that determines if view should be cached.

    • viewAccessCache

      private final ConcurrentHashMap<Object,View> viewAccessCache
      Fast access cache for Views, returning already cached instances without a global lock.

    • viewCreationCache

      private final LinkedHashMap<Object,View> viewCreationCache
      Map from view key to View instance, synchronized for View creation.

  • 构造器详细资料

    • AbstractCachingViewResolver

      public AbstractCachingViewResolver()

  • 方法详细资料

    • setCacheLimit

      public void setCacheLimit(int cacheLimit)
      Specify the maximum number of entries for the view cache. Default is 1024.

    • getCacheLimit

      public int getCacheLimit()
      Return the maximum number of entries for the view cache.

    • setCache

      public void setCache(boolean cache)
      Enable or disable caching.

      This is equivalent to setting the "cacheLimit" property to the default limit (1024) or to 0, respectively.

      Default is "true": caching is enabled. Disable this only for debugging and development.

    • isCache

      public boolean isCache()
      Return if caching is enabled.

    • setCacheUnresolved

      public void setCacheUnresolved(boolean cacheUnresolved)
      Whether a view name once resolved to null should be cached and automatically resolved to null subsequently.

      Default is "true": unresolved view names are being cached, as of Framework 3.1. Note that this flag only applies if the general "cache" flag is kept at its default of "true" as well.

      Of specific interest is the ability for some AbstractUrlBasedView implementations (FreeMarker, Tiles) to check if an underlying resource exists via AbstractUrlBasedView.checkResource(Locale). With this flag set to "false", an underlying resource that re-appears is noticed and used. With the flag set to "true", one check is made only.

    • isCacheUnresolved

      public boolean isCacheUnresolved()
      Return if caching of unresolved views is enabled.

    • setCacheFilter

      public void setCacheFilter(AbstractCachingViewResolver.CacheFilter cacheFilter)
      Sets the filter that determines if view should be cached. Default behaviour is to cache all views.

    • getCacheFilter

      public AbstractCachingViewResolver.CacheFilter getCacheFilter()
      Return filter function that determines if view should be cached.

    • resolveViewName

      @Nullable public View resolveViewName(String viewName, Locale locale) throws Exception
      从接口复制的说明: ViewResolver
      Resolve the given view by name.

      Note: To allow for ViewResolver chaining, a ViewResolver should return null if a view with the given name is not defined in it. However, this is not required: Some ViewResolvers will always attempt to build View objects with the given name, unable to return null (rather throwing an exception when View creation failed).

      指定者:
      resolveViewName 在接口中 ViewResolver
      参数:
      viewName - name of the view to resolve
      locale - the Locale in which to resolve the view. ViewResolvers that support internationalization should respect this.
      返回:
      the View object, or null if not found (optional, to allow for ViewResolver chaining)
      抛出:
      Exception - if the view cannot be resolved (typically in case of problems creating an actual View object)

    • formatKey

      private static String formatKey(Object cacheKey)

    • getCacheKey

      protected Object getCacheKey(String viewName, Locale locale)
      Return the cache key for the given view name and the given locale.

      Default is a String consisting of view name and locale suffix. Can be overridden in subclasses.

      Needs to respect the locale in general, as a different locale can lead to a different view resource.

    • removeFromCache

      public void removeFromCache(String viewName, Locale locale)
      Provides functionality to clear the cache for a certain view.

      This can be handy in case developer are able to modify views (e.g. FreeMarker templates) at runtime after which you'd need to clear the cache for the specified view.

      参数:
      viewName - the view name for which the cached view object (if any) needs to be removed
      locale - the locale for which the view object should be removed

    • clearCache

      public void clearCache()
      Clear the entire view cache, removing all cached view objects. Subsequent resolve calls will lead to recreation of demanded view objects.

    • createView

      @Nullable protected View createView(String viewName, Locale locale) throws Exception
      Create the actual View object.

      The default implementation delegates to loadView(java.lang.String, java.util.Locale). This can be overridden to resolve certain view names in a special fashion, before delegating to the actual loadView implementation provided by the subclass.

      参数:
      viewName - the name of the view to retrieve
      locale - the Locale to retrieve the view for
      返回:
      the View instance, or null if not found (optional, to allow for ViewResolver chaining)
      抛出:
      Exception - if the view couldn't be resolved
      另请参阅:

    • loadView

      @Nullable protected abstract View loadView(String viewName, Locale locale) throws Exception
      Subclasses must implement this method, building a View object for the specified view. The returned View objects will be cached by this ViewResolver base class.

      Subclasses are not forced to support internationalization: A subclass that does not may simply ignore the locale parameter.

      参数:
      viewName - the name of the view to retrieve
      locale - the Locale to retrieve the view for
      返回:
      the View instance, or null if not found (optional, to allow for ViewResolver chaining)
      抛出:
      Exception - if the view couldn't be resolved
      另请参阅: