7:36 a.m.
ksession hasn't been assigned an object when you call ksession.insert
in RuleHandler.java:61.
-W
On 3 August 2010 06:31, Sanjib Karmakar <sanjibk(a)skytechsolutions.co.in> wrote:
Hi
I am new in drools. In my project I have to call the method define in xml
rule file using java
## Following is my rule xml
<?xml version="1.0" encoding="UTF-8"?>
<package name="com.sample"
xmlns="http://drools.org/drools-5.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema-instance"
xs:schemaLocation="http://drools.org/drools-5.0
drools.org/drools-5.0.xsd">
<import name="com.skyfusion.dto.FlifoDTO" />
<global identifier="flifoDTO" type="com.skyfusion.dto.FlifoDTO"
/>
<function return-type="FlifoDTO" name="show">
<parameter identifier="appId" type="FlifoDTO.appId"/>
<body>
System.out.println("appId " + appId);
if(appId==2)
{
flifoDTO.setChnlName("SKYFUSION.UNI.SIMU.TXT.QUEUE");
}
if(appId==3)
{
flifoDTO.setChnlName("SKYFUSION.BASE.MSGFLTR.TXT.TOPIC");
}
</body>
</function>
<rule name="Find Channel">
<lhs>
<pattern identifier="flDTO" object-type="FlifoDTO"
>
<field-constraint field-name="flifoType">
<qualified-identifier-restriction
evaluator="==">FlifoDTO.FLIFO</qualified-identifier-restriction>
</field-constraint>
<field-binding field-name="appId"
identifier="ruleDTO"/>
</pattern>
</lhs>
<rhs>
//System.out.println(ruleDTO);
System.out.println("Find Channel");
//show(appId);
</rhs>
</rule>
</package>
## Following is my DTO class
package com.skyfusion.dto;
public class FlifoDTO
{
public static final int FLIFO = 1;
private String ruleId;
private int appId;
private int flifoType;
private String chnlName;
public FlifoDTO() {
}
public int getAppId() {
return appId;
}
public void setAppId(int appId) {
this.appId = appId;
}
public String getChnlName() {
return chnlName;
}
public void setChnlName(String chnlName) {
this.chnlName = chnlName;
}
public void setRuleId(String ruleId) {
this.ruleId = ruleId;
}
public String getRuleId() {
return ruleId;
}
public int getFlifoType() {
return flifoType;
}
public void setFlifoType(int flifoType) {
this.flifoType = flifoType;
}
}
## Following is my rule execution class
package com.skyfusion.rule.handler;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import com.skyfusion.dto.FlifoDTO;
public class RuleHandler {
private StatefulKnowledgeSession ksession = null;
private KnowledgeBase kbase = null;
public RuleHandler()
{
try {
// load up the knowledge base
kbase = readKnowledgeBase();
ksession = kbase.newStatefulKnowledgeSession();
} catch (Exception t) {
t.printStackTrace();
}
}
private KnowledgeBase readKnowledgeBase()
throws Exception
{
KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.add(ResourceFactory.newClassPathResource("fliforule.xml"),
ResourceType.XDRL);
KnowledgeBuilderErrors errors = kbuilder.getErrors();
if (errors.size() > 0) {
for (KnowledgeBuilderError error: errors) {
System.out.println(error);
}
throw new IllegalArgumentException("Could not parse
knowledge.");
}
KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
return kbase;
}
public FlifoDTO initMessage(String ruleID, FlifoDTO flDTO, int appId, int
type)
throws Exception
{
FlifoDTO flifoDTO = flDTO;
try
{
flifoDTO.setRuleId(ruleID);
flifoDTO.setAppId(appId);
flifoDTO.setFlifoType(type);
ksession.insert(flifoDTO);
ksession.fireAllRules();
}catch(Exception t)
{
t.printStackTrace();
}
return flifoDTO;
}
public static void main(String args[]){
RuleHandler rh = new RuleHandler();
FlifoDTO flifoDTO = new FlifoDTO();
try {
flifoDTO = rh.initMessage("Find Channel",flifoDTO,2,1);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(flifoDTO.getChnlName());
}
}
## I am getting the following exception
java.lang.IllegalArgumentException: Could not parse knowledge.
at
com.skyfusion.rule.handler.RuleHandler.readKnowledgeBase(RuleHandler.java:45)
at com.skyfusion.rule.handler.RuleHandler.<init>(RuleHandler.java:28)
at com.skyfusion.rule.handler.RuleHandler.main(RuleHandler.java:71)
java.lang.NullPointerException
at com.skyfusion.rule.handler.RuleHandler.initMessage(RuleHandler.java:61)
at com.skyfusion.rule.handler.RuleHandler.main(RuleHandler.java:74)
(null: 29, 54): schema_reference.4: Failed to read schema document
'drools.org/drools-5.0.xsd', because 1) could not find the document; 2) the
document could not be read; 3) the root element of the document is not
<xsd:schema>.
(null: 31, 60): schema_reference.4: Failed to read schema document
'drools.org/drools-5.0.xsd', because 1) could not find the document; 2) the
document could not be read; 3) the root element of the document is not
<xsd:schema>.
(null: 34, 7): schema_reference.4: Failed to read schema document
'drools.org/drools-5.0.xsd', because 1) could not find the document; 2) the
document could not be read; 3) the root element of the document is not
<xsd:schema>.
Error importing : 'com.sample.Show.show'
[ show : unable to resolve type while building function
]
[ show : Function Compilation error
show (line:-2): FlifoDTO.appId cannot be resolved to a type
show (line:3): flifoDTO cannot be resolved
show (line:7): flifoDTO cannot be resolved
]
[ show : Function Compilation error
show (line:-2): FlifoDTO.appId cannot be resolved to a type
show (line:3): flifoDTO cannot be resolved
show (line:7): flifoDTO cannot be resolved
]
Rule Compilation error : [Rule name='Find Channel']
com/sample/Rule_Find_Channel_0.java (2:89) : The import com.sample.Show
cannot be resolved
Error importing : 'com.sample.Show.show'
null
## Please let me know I am missing.
Thanks in advance
--
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