Sun Java System Web Server 6.1 SP7 Programmer's Guide to Web Applications

Caching Example

Here is an example cache element in the sun-web.xml file:

<cache max-capacity="8192" timeout="60">
   <cache-helper name="myHelper" class-name="MyCacheHelper"/>
      <servlet-name>myservlet</servlet name>
      <timeout name="timefield">120</timeout>
      <url-pattern> /catalog/* </url-pattern>
      <!-- cache the best selling category; cache the responses to
        -- this resource only when the given parameters exist. cache
        -- only when the catalog parameter has 'lilies' or 'roses'
        -- but no other catalog varieties:
        -- /orchard/catalog?best&category='lilies'
        -- /orchard/catalog?best&category='roses'
        -- but not the result of
        -- /orchard/catalog?best&category='wild'
      <constraint-field name='best' scope='request.parameter'/>
      <constraint-field name='category' scope='request.parameter'>
        <value> roses </value>
        <value> lilies </value>
      <!-- Specify that a particular field is of given range but the
        -- field doesn't need to be present in all the requests -->
      <constraint-field name='SKUnum' scope='request.parameter'>
        <value match-expr='in-range'> 1000 - 2000 </value>
      <!-- cache when the category matches with any value other than
        -- a specific value -->
      <constraint-field name="category" scope="request.parameter>
        <value match-expr="equals" cache-on-match-failure="true">bogus</value>
      <servlet-name> InfoServlet </servlet name>

For more information about the sun-web.xml caching settings, see Caching Elements.