(Issue 16) Fix for deserialization problems with process variables

ActivitiGrailsPlugin.groovy

@@ -21,6 +21,7 @@ import org.codehaus.groovy.grails.commons.ConfigurationHolder as CH
 import org.codehaus.groovy.grails.commons.ControllerArtefactHandler
 import org.springframework.core.io.Resource 
 import org.grails.activiti.ActivitiConstants
+import org.grails.activiti.serializable.SerializableVariableType
 
 /**
  *
@@ -86,6 +87,9 @@ class ActivitiGrailsPlugin {
 		            mailServerDefaultFrom = CH.config.activiti.mailServerDefaultFrom?:ActivitiConstants.DEFAULT_MAIL_SERVER_FROM
 		            dataSource = ref("dataSource")
 		            transactionManager = ref("transactionManager")
+
+                    // Define custom serializable types for fix issue with serialization
+                    customPreVariableTypes = [new SerializableVariableType()]
 		        }
 
 				  processEngine(org.activiti.spring.ProcessEngineFactoryBean) {

src/groovy/org/grails/activiti/serializable/GroovyObjectInputStream.groovy

@@ -0,0 +1,29 @@
+package org.grails.activiti.serializable
+
+/**
+ *
+ * @author <a href='mailto:pais@exigenservices.com'>Ilya Drabenia</a>
+ *
+ * @since 5.8.2
+ */
+class GroovyObjectInputStream extends ObjectInputStream {
+    private ClassLoader myClassLoader;
+
+    public GroovyObjectInputStream(ClassLoader myClassLoader) throws IOException, SecurityException {
+        super();
+        this.myClassLoader = myClassLoader;
+    }
+
+    public GroovyObjectInputStream(InputStream inp, ClassLoader myClassLoader) throws IOException {
+        super(inp);
+        this.myClassLoader = myClassLoader;
+    }
+
+    @Override
+    protected Class resolveClass(ObjectStreamClass desc) throws IOException,
+            ClassNotFoundException {
+        String name = desc.getName();
+        return Class.forName(name, false, new GroovyClassLoader(myClassLoader));
+    }
+
+}

src/groovy/org/grails/activiti/serializable/SerializableVariableType.groovy

@@ -0,0 +1,86 @@
+package org.grails.activiti.serializable
+
+import org.activiti.engine.ActivitiException
+import org.activiti.engine.impl.persistence.entity.VariableInstanceEntity
+import org.activiti.engine.impl.variable.ByteArrayType
+import org.activiti.engine.impl.variable.ValueFields
+import org.activiti.engine.impl.util.IoUtil
+import org.activiti.engine.impl.context.Context
+import org.grails.activiti.serializable.GroovyObjectInputStream
+
+/**
+ *
+ * @author <a href='mailto:pais@exigenservices.com'>Ilya Drabenia</a>
+ *
+ * @since 5.8.2
+ */
+class SerializableVariableType extends ByteArrayType {
+    public static final String TYPE_NAME = "groovySerializable"
+
+    private static final long serialVersionUID = 1L
+
+    String getTypeName() {
+        return TYPE_NAME;
+    }
+
+    Object getValue(ValueFields valueFields) {
+        Object cachedObject = valueFields.getCachedValue()
+        if (cachedObject != null) {
+            return cachedObject
+        }
+        byte[] bytes = (byte[]) super.getValue(valueFields)
+        ByteArrayInputStream bais = new ByteArrayInputStream(bytes)
+        Object deserializedObject = null
+        try {
+            GroovyObjectInputStream ois = new GroovyObjectInputStream(bais, Thread.currentThread().contextClassLoader)
+            deserializedObject = ois.readObject()
+            valueFields.setCachedValue(deserializedObject)
+
+            if (valueFields instanceof VariableInstanceEntity) {
+                Context
+                        .getCommandContext()
+                        .getDbSqlSession()
+                        .addDeserializedObject(deserializedObject, bytes, (VariableInstanceEntity) valueFields)
+            }
+
+        }
+        catch (Exception e) {
+            throw new ActivitiException("coudn't deserialize object in variable '" + valueFields.getName() + "'", e)
+        }
+        finally {
+            IoUtil.closeSilently(bais)
+        }
+        return deserializedObject
+    }
+
+    void setValue(Object value, ValueFields valueFields) {
+        byte[] byteArray = serialize(value, valueFields)
+        valueFields.setCachedValue(value)
+        super.setValue(byteArray, valueFields)
+    }
+
+    static byte[] serialize(Object value, ValueFields valueFields) {
+        if (value == null) {
+            return null
+        }
+        ByteArrayOutputStream baos = new ByteArrayOutputStream()
+        ObjectOutputStream ois = null
+        try {
+            ois = new ObjectOutputStream(baos)
+            ois.writeObject(value)
+        }
+        catch (Exception e) {
+            throw new ActivitiException("coudn't deserialize value '" + value + "' in variable '" + valueFields.getName() + "'", e)
+        }
+        finally {
+            IoUtil.closeSilently(ois)
+        }
+        return baos.toByteArray()
+    }
+
+    boolean isAbleToStore(Object value) {
+        return value instanceof Serializable;
+    }
+}
+
+

test/integration/org/grails/activiti/flow/variable/FakeFlowVariable.groovy

@@ -0,0 +1,9 @@
+package org.grails.activiti.flow.variable
+
+/**
+ * @author Ilya Drabenia
+ */
+class FakeFlowVariable implements Serializable {
+    String name
+    int age
+}

test/integration/org/grails/activiti/flow/variable/SampleProcess.bpmn20.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:activiti="http://activiti.org/bpmn"
+             xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
+             xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI"
+             typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath"
+             targetNamespace="http://www.activiti.org/test">
+  <process id="sampleProcess" name="sampleProcess">
+    <startEvent id="startevent1" name="Start"></startEvent>
+    <userTask id="usertask1" name="User Task" activiti:assignee="qa"></userTask>
+    <serviceTask id="servicetask1" name="Service Task" activiti:expression="${&quot;Service Task&quot;}"></serviceTask>
+    <sequenceFlow id="flow1" name="" sourceRef="startevent1" targetRef="usertask1"></sequenceFlow>
+    <sequenceFlow id="flow2" name="" sourceRef="usertask1" targetRef="servicetask1"></sequenceFlow>
+    <endEvent id="endevent1" name="End"></endEvent>
+    <sequenceFlow id="flow3" name="" sourceRef="servicetask1" targetRef="endevent1"></sequenceFlow>
+  </process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_sampleProcess">
+    <bpmndi:BPMNPlane bpmnElement="sampleProcess" id="BPMNPlane_sampleProcess">
+      <bpmndi:BPMNShape bpmnElement="startevent1" id="BPMNShape_startevent1">
+        <omgdc:Bounds height="35" width="35" x="555" y="90"></omgdc:Bounds>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
+        <omgdc:Bounds height="55" width="105" x="520" y="170"></omgdc:Bounds>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape bpmnElement="servicetask1" id="BPMNShape_servicetask1">
+        <omgdc:Bounds height="55" width="105" x="520" y="280"></omgdc:Bounds>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape bpmnElement="endevent1" id="BPMNShape_endevent1">
+        <omgdc:Bounds height="35" width="35" x="555" y="380"></omgdc:Bounds>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge bpmnElement="flow1" id="BPMNEdge_flow1">
+        <omgdi:waypoint x="572" y="125"></omgdi:waypoint>
+        <omgdi:waypoint x="572" y="170"></omgdi:waypoint>
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
+        <omgdi:waypoint x="572" y="225"></omgdi:waypoint>
+        <omgdi:waypoint x="572" y="280"></omgdi:waypoint>
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge bpmnElement="flow3" id="BPMNEdge_flow3">
+        <omgdi:waypoint x="572" y="335"></omgdi:waypoint>
+        <omgdi:waypoint x="572" y="380"></omgdi:waypoint>
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</definitions>

test/integration/org/grails/activiti/flow/variable/VariableSerializationTests.groovy

@@ -0,0 +1,37 @@
+package org.grails.activiti.flow.variable
+
+import org.activiti.engine.RuntimeService
+import org.activiti.engine.TaskService
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+import org.activiti.engine.RepositoryService
+
+/**
+ *
+ * @author <a href='mailto:pais@exigenservices.com'>Ilya Drabenia</a>
+ *
+ * @since 5.8.2
+ */
+class VariableSerializationTests {
+    RuntimeService runtimeService
+    RepositoryService repositoryService
+
+    @Test
+    void testSettingAndGettingOfProcessVariable() {
+        repositoryService.createDeployment()
+            .addClasspathResource("org/grails/activiti/flow/variable/SampleProcess.bpmn20.xml")
+            .name("sampleProcess")
+            .deploy()
+
+        // start process
+        def process = runtimeService.startProcessInstanceByKey("sampleProcess")
+
+        // check flow variables
+        runtimeService.setVariable(process.processInstanceId, "var1", new FakeFlowVariable(name: 'Matt', age: 21))
+        def flowVariable = (FakeFlowVariable) runtimeService.getVariable(process.processInstanceId, "var1")
+
+        // kill process
+        runtimeService.deleteProcessInstance(process.id, "Test is completed")
+    }
+}