1:56 a.m.
Yingzhi Wang created JBRULES-3617:
-------------------------------------
Summary: NullpointerException in Accumulate when use query
Key: JBRULES-3617
URL: https://issues.jboss.org/browse/JBRULES-3617
Project: Drools
Issue Type: Bug
Security Level: Public (Everyone can see)
Components: drools-core (expert)
Affects Versions: 5.4.0.Final
Environment: OS: Windows xp
IDE: Eclipse
JRE: 1.6
Reporter: Yingzhi Wang
Assignee: Mark Proctor
Priority: Minor
FACT: Person
package test;
public class Persion {
private String firstname;
private String secondname;
private String address;
public Persion() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Persion
import java.util.HashSet
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Persion($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Persion p = new Persion();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
--
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11:27 p.m.
[
https://issues.jboss.org/browse/JBRULES-3617?page=com.atlassian.jira.plug...
]
Yingzhi Wang updated JBRULES-3617:
----------------------------------
Priority: Critical (was: Minor)
NullpointerException in Accumulate when use query
-------------------------------------------------
Key: JBRULES-3617
URL: https://issues.jboss.org/browse/JBRULES-3617
Project: Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: drools-core (expert)
Affects Versions: 5.4.0.Final
Environment: OS: Windows xp
IDE: Eclipse
JRE: 1.6
Reporter: Yingzhi Wang
Assignee: Mark Proctor
Priority: Critical
Labels: Accumulate, query, reverse
FACT: Person
package test;
public class Persion {
private String firstname;
private String secondname;
private String address;
public Persion() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Persion
import java.util.HashSet
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Persion($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Persion p = new Persion();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
--
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1:23 a.m.
[
https://issues.jboss.org/browse/JBRULES-3617?page=com.atlassian.jira.plug...
]
Yingzhi Wang updated JBRULES-3617:
----------------------------------
Description:
FACT: Person
package test;
public class Person {
private String firstname;
private String secondname;
private String address;
public Person() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Person
import java.util.HashSet
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Person($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Person p = new Person();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
was:
FACT: Person
package test;
public class Persion {
private String firstname;
private String secondname;
private String address;
public Persion() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Persion
import java.util.HashSet
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Persion($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Persion p = new Persion();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Persion(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
NullpointerException in Accumulate when use query
-------------------------------------------------
Key: JBRULES-3617
URL: https://issues.jboss.org/browse/JBRULES-3617
Project: Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: drools-core (expert)
Affects Versions: 5.4.0.Final
Environment: OS: Windows xp
IDE: Eclipse
JRE: 1.6
Reporter: Yingzhi Wang
Assignee: Mark Proctor
Priority: Critical
Labels: Accumulate, query, reverse
FACT: Person
package test;
public class Person {
private String firstname;
private String secondname;
private String address;
public Person() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Person
import java.util.HashSet
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Person($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Person p = new Person();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
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2:35 a.m.
[
https://issues.jboss.org/browse/JBRULES-3617?page=com.atlassian.jira.plug...
]
Mario Fusco commented on JBRULES-3617:
--------------------------------------
The problem arises when you try to concurrently modify a rulebase while another thread is
already using the knowledge session. Originally I thought the problem was caused by a race
condition, but this is not the case. Edson suggested that it could have been caused by the
shared alpha node or anyway by the Rete network being not correctly created, but also this
is not completely correct. So let me explain step by step what happens in reality:
1. A new package is added to the knowledge base. That triggers a modification of the
rulebase and then a write lock is acquired on it. At the end of this process the Rete
network will look as it follows:
[EntryPointNode(1) EntryPoint::DEFAULT ]
[ObjectTypeNode(2)::EntryPoint::DEFAULT objectType=[ClassObjectType
class=org.drools.integrationtests.JbRules3617$Person] expiration=-1ms ]
[AlphaNode(7) constraint=firstname == "Tom"]
[AlphaNode(11) constraint=secondname == "Cat"]
[ AccumulateNode(12) ]
[RuleTerminalNode(14): rule=test]
[JoinNode(8) - [ClassObjectType
class=org.drools.integrationtests.JbRules3617$Person]]
[QueryTerminalNode(9): query=find]
2. In the meanwhile the other thread is trying to update a fact. Since the main thread is
modifying the rulebase it will wait acquiring a read lock on it (NamedEntryPoint#389).
3. The Rete builder creates the JoinNode and when it gets attached to the Rete it
propagates a sink update on the Alpha and on the ObjectType nodes. This last one triggers
an assertObject of the (only one) fact handle in its memory. Since the fact satisfies the
constraint of the alpha node (the Person's name is "Tom") the assertObject
is propagated to the JoinNode that creates a new RightTuple. This RightTuple (having the
JoinNode as sink) is added to the FactHandle itself.
4. The Rete builder creates the AccumulateNode. Following exactly the same path of the
former point, when it gets attached to the Rete, a second RightTuple (having the
AccumulateNode as sink) is added to the FactHandle. Moreover, the same FactHandle is also
accumulated by the AccumulateNode. I am reporting below the source code of the generated
accumulator because it will be useful to better explain what happens in the following
steps:
public class Accumulate0 implements java.io.Serializable {
private java.util.Map reverseMap = new java.util.HashMap<Integer,
ReverseSnapshot>();
private HashSet set;
public Accumulate0() { }
public void init() throws Exception {
set = new HashSet();
}
public void accumulate(org.drools.WorkingMemory workingMemory,
org.drools.common.InternalFactHandle handle,
org.drools.rule.Declaration[] innerDeclarations,
Object object,
java.lang.String $addr) throws Exception {
this.reverseMap.put( Integer.valueOf( handle.getId() ),
new ReverseSnapshot( $addr ) );
set.add($addr);
}
public void reverse(org.drools.WorkingMemory workingMemory,
org.drools.common.InternalFactHandle handle,
Object object ) throws Exception {
ReverseSnapshot snapshot = (ReverseSnapshot) this.reverseMap.remove(
Integer.valueOf( handle.getId() ) );
java.lang.String $addr = snapshot.$addr;
set.remove($addr);
}
public Object getResult( ) throws Exception {
return ( set );
}
public boolean supportsReverse() {
return true;
}
private static class ReverseSnapshot implements java.io.Serializable {
public final java.lang.String $addr;
public ReverseSnapshot( final java.lang.String $addr ) {
this.$addr = $addr;
}
}
}
5. The building process of the Rete network is finished so the main thread has released
the write lock on it. The concurrent one can finally acquire the read lock and go forward
with the fact update. In the EntryPointNode.modifyObject method a new ModifyPreviousTuples
is created (EntryPointNode#260) and here it comes my first doubt: for what said in the
former steps the FactHandle now has 2 RightTuples, one having the JoinNode as sink and the
other having the AccumulateNode, but for some reason only the first one is carried in the
ModifyPreviousTuples object. Is this (always) correct?
6. The object modification hits the AccumulateNode. Here (BetaNode#520) the RightTupleSink
in the ModifyPreviousTuples (the JoinNode) is different from the current node (the
AccumulateNode), or more in details their rightInputOtnIds are different. This is the main
cause of the bug because, for this reason, the RightTuple is NOT removed from the
ModifyPreviousTuples and the FactHandle is asserted (again) on the AccumulateNode. It
means that the accumulate method of the Accumulator (see code above) is called again with
the same FactHandle and a new ReverseSnapshot replaces the existing in the reverseMap.
7. At the end of the EntryPointNode.modifyObject method (EntryPointNode#301), since the
ModifyPreviousTuples still has a RightTuple having the AccumulateNode as sink, the
AccumulateNode itself retracts the FactHandle by invoking the reverse method of its
Accumulator. Here the ReverseSnapshot corresponding to the (only) accumulated fact is
removed leaving the reverseMap empty.
8. The infinite loop in the concurrent thread tries to update the same FactHandle again.
This time the Rete network isn't changed so the update is correctly propagated calling
the modifyRightTuple method of the AccumulateNode. Here the AccumulateNode tries to remove
the FactHandle from the Accumulator before to add it again, but when it invokes the
reverse method the reverseMap is empty, so the ReverseSnapshot is null and the subsequent
statement throws the NPE reported in the jira ticket.
NullpointerException in Accumulate when use query
-------------------------------------------------
Key: JBRULES-3617
URL: https://issues.jboss.org/browse/JBRULES-3617
Project: Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: drools-core (expert)
Affects Versions: 5.4.0.Final
Environment: OS: Windows xp
IDE: Eclipse
JRE: 1.6
Reporter: Yingzhi Wang
Assignee: Mark Proctor
Priority: Critical
Labels: Accumulate, query, reverse
FACT: Person
package test;
public class Person {
private String firstname;
private String secondname;
private String address;
public Person() {
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSecondname() {
return secondname;
}
public void setSecondname(String secondname) {
this.secondname = secondname;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
r1.drl:
package test1
import test.Person
import java.util.HashSet
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
rule "test"
no-loop true
when
$list: HashSet( size >= 0 )
from accumulate (
Person($addr: address, firstname=="Tom", secondname=="Cat"),
init ( HashSet set = new HashSet(); ),
action ( set.add($addr); ),
reverse ( set.remove($addr); ),
result(set) )
then
System.out.println("It' OK~!");
end
Test.java
package test;
import java.util.Collection;
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.definition.KnowledgePackage;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.rule.FactHandle;
public class Test {
public static void main(String[] args) throws Exception {
new Test().test();
}
public void test() throws Exception {
KnowledgeBase base = KnowledgeBaseFactory.newKnowledgeBase();
StatefulKnowledgeSession s = base.newStatefulKnowledgeSession();
new Th(s).start();
Thread.sleep(2000);
KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder();
builder.add(ResourceFactory.newClassPathResource("r1.drl", getClass()),
ResourceType.DRL);
KnowledgeBuilderErrors errs = builder.getErrors();
if (!errs.isEmpty()) {
for (KnowledgeBuilderError e: errs) {
System.out.println(e.toString());
}
}
Collection<KnowledgePackage> col = builder.getKnowledgePackages();
base.addKnowledgePackages(col);
}
class Th extends Thread {
StatefulKnowledgeSession s;
public Th(StatefulKnowledgeSession s) {
this.s = s;
}
public void run() {
Person p = new Person();
p.setFirstname("Tom");
p.setSecondname("Cat");
p.setAddress("Mars");
FactHandle fact = s.insert(p);
int i=0;
while (true) {
s.update(fact, p);
s.fireAllRules();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
i++;
}
}
}
}
Run Test.java, will throws Exception:
Exception in thread "Thread-0" org.drools.RuntimeDroolsException:
java.lang.NullPointerException
at org.drools.rule.Accumulate.reverse(Accumulate.java:212)
at org.drools.reteoo.AccumulateNode.removeMatch(AccumulateNode.java:902)
at org.drools.reteoo.AccumulateNode.modifyRightTuple(AccumulateNode.java:537)
at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:531)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68)
at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157)
at
org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421)
at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265)
at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:960)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:933)
at
org.drools.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:284)
at test.Test$Th.run(Test.java:53)
Caused by: java.lang.NullPointerException
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1$Accumulate0.reverse(Rule_test_b59970efe0844a8d8797758b863454b1.java:52)
at
test1.Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.reverse(Rule_test_b59970efe0844a8d8797758b863454b1Accumulate0Invoker.java:69)
at org.drools.rule.Accumulate.reverse(Accumulate.java:203)
... 16 more
But, if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "111", secondname==$second)
end
It will be ok.
However if I change the query to like this:
query find(String $first, String $second)
p: Person(firstname == "Tom", secondname==$second)
end
It will throws Exception again.
firstname=="Tom" is a condition of rule "test"
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4547
days inactive
4572
days old
3 comments
2 participants
participants (2)
-
Mario Fusco (JIRA) -
Yingzhi Wang (JIRA)