Idgenerator and metadatagenerator sub-elements
Use the Idgenerator element to specify the class name that is loaded for the generation of the cache ID. The Idgenerator element must implement the com.ibm.websphere.servlet.cache.Idgenerator interface for a servlet or the com.ibm.websphere.webservices.Idgenerator interface for the Web services client cache. An example of the Idgenerator element follows:
<Idgenerator> class name </Idgenerator>
Class name is the fully qualified name of the class to use. Define this generator class in a shared library. Example | -30 shows an example of a custom written command cache ID generator.
Example 6-30 Cache ID generator for a command object
package com.ibm.ws.cache.command;
import com.ibm.websphere.command.*;
import java.util.*;
public class QuoteIdgenerator implements CommandIdgenerator {
public String getId(CacheableCommand command, ArrayList groupIds) {
QuoteCommand cs = (QuoteCommand)command;
// add dependency ids for quotecommand the ticker for this command
groupIds.add("QuoteCommandIDGen");
groupIds.add("ticker:"+cs.getTicker());
return "QuoteCommmandIdGen Ticker:"+cs.getTicker();
}
}
Use the metadatagenerator element inside the cache-id element to specify the class name loaded for the metadata generation. The MetaDataGenerator class must implement the com.ibm.websphere.servlet.cache.MetaDataGenerator interface for a servlet or the com.ibm.websphere.cache.webservices.MetaDataGenerator interface for Web services client cache. The MetaDataGenerator class defines properties like timeout, inactivity, external caching properties or dependencies. An example of the metadatagenerator element is:
<metadatagenerator> class name </metadatagenerator>
In this example, class name is the fully qualified name of the class to use. Define this generator class in a shared library.
Example 6-31 Sample metadata generator source code
package com.ibm.ws.cache.servlet;
import javax.servlet.http.*;
import com.ibm.websphere.servlet.cache.*;
public class MyMetaDataGenerator implements MetaDataGenerator {
private int timeout=0;
private int priority=0;
public void setMetaData(ServletCacheRequest req, HttpServletResponse resp) {
System.out.println("**** setMetaData***");
FragmentInfo fragmentInfo = (FragmentInfo) req.getFragmentInfo();
String tout = req.getParameter("metaDataTimeout");
if (tout != null) {
timeout = new Integer(tout).intValue();
if (timeout != 0) {
fragmentInfo.setTimeLimit(timeout);
}
}
String pri = req.getParameter("metaDataPriority");
if (pri != null) {
priority = new Integer(pri).intValue();
if (priority!=0) {
fragmentInfo.setPriority(priority);
}
}
}
public void initialize(CacheConfig cc) {
}
}
