Customizing the ruleset cache

Using the XU ruleset API, you can customize the ruleset cache by writing your own implementation class and modifying the XU deployment descriptor accordingly.

To customize a ruleset cache named mypackage.MyRulesetCache:

1. Implement the interface IlrRulesetCache.

   package ilog.rules.res.xu.ruleset.cache.sample;
   
   import java.util.*;
   import java.util.logging.*;
   
   import ilog.rules.res.xu.ruleset.*;
   
   public class RulesetCacheImpl implements IlrRulesetCache {
   	public static final int DEFAULT_MAXIMUM_SIZE = 2;
   
   	protected IlrRulesetUsageInformationMonitor monitor;
   	protected Logger logger;
   	protected ArrayList<IlrXURuleset> rulesets = new ArrayList<IlrXURuleset>();
   
   	/** Maximum number of rulesets that can be stored in the cache */
   	protected int maxSize = DEFAULT_MAXIMUM_SIZE;
   
   	public synchronized void addRuleset(IlrXURuleset ruleset) {
   		if (rulesets.size() == maxSize) {
   			logger.info("Max size reached, removing less used ruleset");
   			removeLessUsedRuleset();
   		}
   		rulesets.add(ruleset);
   	}
   
   
   	/**
   	 * Removes the least executed ruleset.
   	 */
   	protected void removeLessUsedRuleset() {
   		long minExecCount = Long.MAX_VALUE;
   		IlrXURuleset minExecRuleset = null;
   
   		for(IlrXURuleset ruleset: rulesets) {
   			IlrRulesetUsageInformation info
   				= monitor.getRulesetUsageInformation(ruleset.getCanonicalRulesetPath());
   			long execCounter = info.getExecutionCount();
   
   			if (execCounter <= minExecCount) {
   				minExecRuleset = ruleset;
   				minExecCount = execCounter;
   			}
   		}
   
   		if (minExecRuleset != null) {
   			logger.info("Remove ruleset: "+minExecRuleset.getCanonicalRulesetPath());
   			rulesets.remove(minExecRuleset);
   		}
   	}
   
   	public synchronized void clear() {
   		rulesets.clear();
   	}
   
   	public synchronized IlrXURuleset getDeprecatedRuleset(String canonicalRulesetPath,
   			ClassLoader xomClassLoader) {
   		return null;
   	}
   
   	public synchronized IlrXURuleset getRuleset(String canonicalRulesetPath,
   			ClassLoader xomClassLoader) {
   		for(IlrXURuleset ruleset: rulesets) {
   			if (ruleset.getCanonicalRulesetPath().equals(canonicalRulesetPath) &&
   					ruleset.getXOMClassLoader() == xomClassLoader) {
   				return ruleset;
   			}
   		}
   
   		return null;
   	}
   
   	public void initialize(Logger logger, Map<String, String> properties,
   			IlrRulesetUsageInformationMonitor monitor)
   			throws IlrRulesetCacheException {
   		this.monitor = monitor;
   		this.logger = logger;
   	}
   
   	public synchronized void rulesetChanged(String canonicalRulesetPath) {
   		Iterator<IlrXURuleset> iterator = rulesets.iterator();
   		while(iterator.hasNext()) {
   			IlrXURuleset ruleset = iterator.next();
   			if (ruleset.getCanonicalRulesetPath().equals(canonicalRulesetPath)) {
   				iterator.remove();
   			}
   		}
   	}
   
   }
    

2. Add the implementation class to the XU deployment descriptor.

   <config-property>
   <config-property-name>rulesetCacheProperties<config-property-name> 
   <config-property-type>java.lang.String</config-property-type> 
   <config-property-value>ruleset.cache.class=mypackage.MyRulesetCache</config-property-value> 
   </config-property><config-property>
   
   <config-property-name>rulesetCacheProperties</config-property-name> 
   <config-property-type>java.lang.String<config-property-type> 
   <config-propertyvalue>ruleset.cache.class=mypackage.MyRulesetCache
   <mycustomprop=mycustomvalue/config-property-value>
   </config-property>
   
   <config-property>
   <config-property-name>rulesetUsageMonitorEnabled</config-property-name>
   <config-property-type>java.lang.Boolean</config-property-type> 
   <config-property-value>true/config-property-value>
   </config-property>

3. Package the class.

   For a Java™ SE deployment, you must add the class to the same class path as the XU or its parent. In Java EE, you must package the class in the XU .rar file.