How to load multiple DRL Rule Files using JSR 94 Template

[mpaluru]

Please help me how to load multiple rules using JSR94 template. I saw the example also there loading only one DRL file using JSR94 template. Ideal case we have to maintain multiple DRL files each drl file contains corresponding functionality rules.

[dean]

Try this.

import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.rmi.RemoteException;
import java.util.Map;

import javax.rules.admin.RuleExecutionSet;
import javax.rules.admin.RuleExecutionSetCreateException;
import javax.rules.admin.RuleExecutionSetRegisterException;

import org.drools.decisiontable.SpreadsheetCompiler;
import org.springframework.core.io.Resource;
import org.springmodules.jsr94.rulesource.AbstractRuleSource;

/**
 * 
 * 
 *
 */
public class MultipleWorksheetDecisionTableRuleSource extends AbstractRuleSource {

	private Resource source;
	private Map providerProperties;
	private Map rulesetProperties;
	private Map registrationProperties;
	
	
	/**
	 * Map<String workssheet name, String bind uri>
	 */
	private Map<String, String> worksheets;
	 
	public void setProviderProperties(Map providerProperties) {
		this.providerProperties = providerProperties;
	}

	public void setRegistrationProperties(Map registrationProperties) {
		this.registrationProperties = registrationProperties;
	}

	public void setRulesetProperties(Map rulesetProperties) {
		this.rulesetProperties = rulesetProperties;
	}

	public void setSource(Resource source) {
		this.source = source;
	}
	
	public void setWorksheets(Map<String, String> worksheets) {
		this.worksheets = worksheets;
	}

	protected void registerRuleExecutionSets()
			throws RuleExecutionSetCreateException, RemoteException,
			IOException, RuleExecutionSetRegisterException {
		
		if (logger.isDebugEnabled()) {
			logger.debug("Registering " + this.worksheets.size() + " worksheets.");
		}
		SpreadsheetCompiler compiler = new SpreadsheetCompiler();
		
		for (String worksheet: this.worksheets.keySet()) {
			
			String drl = compiler.compile(getSpreadsheetStream(), worksheet);
			
			RuleExecutionSet ruleExecutionSet = ruleAdministrator.getLocalRuleExecutionSetProvider(providerProperties).createRuleExecutionSet(new StringReader(drl), rulesetProperties);
			String bindUri = this.worksheets.get(worksheet);
			if (logger.isDebugEnabled()) {
				logger.debug("Rules for worksheet '" + worksheet + "' created. Binding to uri '" + bindUri + "'.");
			}
			ruleAdministrator.registerRuleExecutionSet(bindUri, ruleExecutionSet, registrationProperties);
		}
		if (logger.isDebugEnabled()) {
			logger.debug("Registered all worksheets.");
		}
		
	}

	private InputStream getSpreadsheetStream() throws IOException {
    	InputStream stream = null;
    	try {
    		if (logger.isDebugEnabled()) {
    			try {
	    			logger.debug("Rule source:" + (source.getURL() != null ? " URL = " + source.getURL() : (source.getFilename() != null ? "File name = " + source.getFilename() : "")));
    			}
    			catch (Exception e) {
    				
    			}
    		}
			stream = source.getInputStream();
		} catch (IOException e) {
			logger.error("Problem loading resource: " + (source.getURL() != null ? source.getURL() : source.getFilename()));
			throw e;
		}
    	return stream;
	}

	

}

Sample Spring config

    <bean id="ruleServiceProvider"
          class="org.springmodules.jsr94.factory.DefaultRuleServiceProviderFactoryBean">
      <property name="provider"><value>http://drools.org/</value></property>
      <property name="providerClass">
        <value>org.drools.jsr94.rules.RuleServiceProviderImpl</value>
      </property>
    </bean>

    <bean id="ruleRuntime" class="org.springmodules.jsr94.factory.RuleRuntimeFactoryBean">
      <property name="serviceProvider"><ref local="ruleServiceProvider"/></property>
    </bean>

    <bean id="ruleAdministrator" class="org.springmodules.jsr94.factory.RuleAdministratorFactoryBean">
      <property name="serviceProvider"><ref local="ruleServiceProvider"/></property>
    </bean>

    <bean id="ruleSource" class="au.com.bupa.services.facade.rules.utils.MultipleWorksheetDecisionTableRuleSource">
      <property name="ruleRuntime"><ref local="ruleRuntime"/></property>
      <property name="ruleAdministrator"><ref local="ruleAdministrator"/></property>
      <property name="source"><value>classpath:/spreadsheet.xls</value></property>
      <property name="worksheets">
      	<map>
      		<entry key="worksheet1" value="Rule_Uri_1"/>
      		<entry key="worksheet2" value="Rule_Uri_2"/>
      	</map>
      </property>

    </bean>
    
    

    <!-- Jsr94Template -->
	<bean id="jsr94Template" class="org.springmodules.jsr94.core.Jsr94Template">
		<property name="ruleSource">
			<ref local="ruleSource"/>
		</property>
	</bean>

This is used against a spreadsheet with multiple worksheets. But you could modify it to use different drl files.

E.g. Change the worksheets Map to Map<String, Resource> worksheets and the config to be:

<map>
      		<entry key="Bind_Uri_1" value="classpath:/path/to/file_1.drl"/>
      		<entry key="Bind_Uri_2" value="classpath:/path?to/file_2.drl"/>
      	</map>

... although I haven't tried this modification myself to see if it works.