Merge branch 'master' of https://github.com/roberthafner/Activiti

modules/activiti-bpmn-converter/src/main/java/org/activiti/bpmn/constants/BpmnXMLConstants.java

@@ -168,6 +168,7 @@ public interface BpmnXMLConstants {
   public static final String ATTRIBUTE_TASK_SERVICE_DELEGATEEXPRESSION = "delegateExpression";
   public static final String ATTRIBUTE_TASK_SERVICE_RESULTVARIABLE = "resultVariableName";
   public static final String ATTRIBUTE_TASK_SERVICE_EXTENSIONID = "extensionId";
+  public static final String ATTRIBUTE_TASK_SERVICE_SKIP_EXPRESSION = "skipExpression";
   
   public static final String ATTRIBUTE_TASK_USER_ASSIGNEE = "assignee";
   public static final String ATTRIBUTE_TASK_USER_OWNER = "owner";
@@ -176,6 +177,7 @@ public interface BpmnXMLConstants {
   public static final String ATTRIBUTE_TASK_USER_DUEDATE = "dueDate";
   public static final String ATTRIBUTE_TASK_USER_CATEGORY = "category";
   public static final String ATTRIBUTE_TASK_USER_PRIORITY = "priority";
+  public static final String ATTRIBUTE_TASK_USER_SKIP_EXPRESSION = "skipExpression";
   
   public static final String ATTRIBUTE_TASK_RULE_VARIABLES_INPUT = "ruleVariablesInput";
   public static final String ATTRIBUTE_TASK_RULE_RESULT_VARIABLE = "resultVariable";
@@ -194,6 +196,7 @@ public interface BpmnXMLConstants {
   public static final String ELEMENT_FLOW_CONDITION = "conditionExpression";
   public static final String ATTRIBUTE_FLOW_SOURCE_REF = "sourceRef";
   public static final String ATTRIBUTE_FLOW_TARGET_REF = "targetRef";
+  public static final String ATTRIBUTE_FLOW_SKIP_EXPRESSION = "skipExpression";
   
   public static final String ELEMENT_TEXT_ANNOTATION = "textAnnotation";
   public static final String ATTRIBUTE_TEXTFORMAT = "textFormat";

modules/activiti-bpmn-converter/src/main/java/org/activiti/bpmn/converter/SequenceFlowXMLConverter.java

@@ -42,6 +42,7 @@ public class SequenceFlowXMLConverter extends BaseBpmnXMLConverter {
     sequenceFlow.setSourceRef(xtr.getAttributeValue(null, ATTRIBUTE_FLOW_SOURCE_REF));
     sequenceFlow.setTargetRef(xtr.getAttributeValue(null, ATTRIBUTE_FLOW_TARGET_REF));
     sequenceFlow.setName(xtr.getAttributeValue(null, ATTRIBUTE_NAME));
+    sequenceFlow.setSkipExpression(xtr.getAttributeValue(null, ATTRIBUTE_FLOW_SKIP_EXPRESSION));
     
     parseChildElements(getXMLElementName(), sequenceFlow, model, xtr);
     
@@ -53,6 +54,10 @@ public class SequenceFlowXMLConverter extends BaseBpmnXMLConverter {
     SequenceFlow sequenceFlow = (SequenceFlow) element;
     writeDefaultAttribute(ATTRIBUTE_FLOW_SOURCE_REF, sequenceFlow.getSourceRef(), xtw);
     writeDefaultAttribute(ATTRIBUTE_FLOW_TARGET_REF, sequenceFlow.getTargetRef(), xtw);
+    if(StringUtils.isNotEmpty(sequenceFlow.getSkipExpression()))
+    {
+      writeDefaultAttribute(ATTRIBUTE_FLOW_SKIP_EXPRESSION, sequenceFlow.getSkipExpression(), xtw);
+    }
   }
   
   @Override

modules/activiti-bpmn-converter/src/main/java/org/activiti/bpmn/converter/ServiceTaskXMLConverter.java

@@ -67,6 +67,9 @@ public class ServiceTaskXMLConverter extends BaseBpmnXMLConverter {
 		serviceTask.setType(xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TYPE));
 		serviceTask.setExtensionId(xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_SERVICE_EXTENSIONID));
 	
+		if (StringUtils.isNotEmpty(xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_SERVICE_SKIP_EXPRESSION))) {
+		  serviceTask.setSkipExpression(xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_SERVICE_SKIP_EXPRESSION));
+		}
 		parseChildElements(getXMLElementName(), serviceTask, model, xtr);
 		
 		return serviceTask;
@@ -94,6 +97,10 @@ public class ServiceTaskXMLConverter extends BaseBpmnXMLConverter {
     if (StringUtils.isNotEmpty(serviceTask.getExtensionId())) {
       writeQualifiedAttribute(ATTRIBUTE_TASK_SERVICE_EXTENSIONID, serviceTask.getExtensionId(), xtw);
     }
+    if(StringUtils.isNotEmpty(serviceTask.getSkipExpression()))
+    {
+      writeQualifiedAttribute(ATTRIBUTE_TASK_SERVICE_SKIP_EXPRESSION, serviceTask.getSkipExpression(), xtw);
+    }
   }
   
   @Override

modules/activiti-bpmn-converter/src/main/java/org/activiti/bpmn/converter/UserTaskXMLConverter.java

@@ -48,7 +48,8 @@ public class UserTaskXMLConverter extends BaseBpmnXMLConverter {
       new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_PRIORITY), 
       new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_CANDIDATEUSERS), 
       new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_CANDIDATEGROUPS),
-      new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_CATEGORY)
+      new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_CATEGORY),
+      new ExtensionAttribute(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_SKIP_EXPRESSION)
   );
 
   public UserTaskXMLConverter() {
@@ -100,6 +101,11 @@ public class UserTaskXMLConverter extends BaseBpmnXMLConverter {
       userTask.getCandidateGroups().addAll(parseDelimitedList(expression));
     }
 
+    if (StringUtils.isNotEmpty(xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_SKIP_EXPRESSION))) {
+      String expression = xtr.getAttributeValue(ACTIVITI_EXTENSIONS_NAMESPACE, ATTRIBUTE_TASK_USER_SKIP_EXPRESSION);
+      userTask.setSkipExpression(expression);
+    }
+
     BpmnXMLUtil.addCustomAttributes(xtr, userTask, defaultElementAttributes, 
         defaultActivityAttributes, defaultUserTaskAttributes);
 
@@ -122,6 +128,10 @@ public class UserTaskXMLConverter extends BaseBpmnXMLConverter {
     if (userTask.getPriority() != null) {
       writeQualifiedAttribute(ATTRIBUTE_TASK_USER_PRIORITY, userTask.getPriority().toString(), xtw);
     }
+    if(null != userTask.getSkipExpression())
+    {
+      writeQualifiedAttribute(ATTRIBUTE_TASK_USER_SKIP_EXPRESSION, userTask.getSkipExpression(), xtw);
+    }
     // write custom attributes
     BpmnXMLUtil.writeCustomAttributes(userTask.getAttributes().values(), xtw, defaultElementAttributes, 
         defaultActivityAttributes, defaultUserTaskAttributes);

modules/activiti-bpmn-converter/src/main/resources/org/activiti/impl/bpmn/parser/Semantic.xsd

@@ -1373,6 +1373,7 @@
 				<xsd:attribute name="sourceRef" type="xsd:IDREF" use="required"/>
 				<xsd:attribute name="targetRef" type="xsd:IDREF" use="required"/>
 				<xsd:attribute name="isImmediate" type="xsd:boolean" use="optional"/>
+				<xsd:attribute name="skipExpression" type="xsd:string" use="optional"/>
 			</xsd:extension>
 		</xsd:complexContent>
 	</xsd:complexType>
@@ -1383,6 +1384,7 @@
 			<xsd:extension base="tTask">
 				<xsd:attribute name="implementation" type="tImplementation" default="##WebService"/>
 				<xsd:attribute name="operationRef" type="xsd:QName" use="optional"/>
+				<xsd:attribute name="skipExpression" type="xsd:string" use="optional"/>
 			</xsd:extension>
 		</xsd:complexContent>
 	</xsd:complexType>	
@@ -1555,6 +1557,7 @@
 					<xsd:element ref="rendering" minOccurs="0" maxOccurs="unbounded"/>
 				</xsd:sequence>
 				<xsd:attribute name="implementation" type="tImplementation" default="##unspecified"/>
+				<xsd:attribute name="skipExpression" type="xsd:string" use="optional"/>
 			</xsd:extension>
 		</xsd:complexContent>
 	</xsd:complexType>

modules/activiti-bpmn-model/src/main/java/org/activiti/bpmn/model/SequenceFlow.java

@@ -23,6 +23,7 @@ public class SequenceFlow extends FlowElement {
   protected String conditionExpression;
   protected String sourceRef;
   protected String targetRef;
+  protected String skipExpression;
   
   public SequenceFlow() {
   	
@@ -51,6 +52,12 @@ public class SequenceFlow extends FlowElement {
   public void setTargetRef(String targetRef) {
     this.targetRef = targetRef;
   }
+  public String getSkipExpression() {
+    return skipExpression;
+  }
+  public void setSkipExpression(String skipExpression) {
+    this.skipExpression = skipExpression;
+  }
   public String toString() {
     return sourceRef + " --> " + targetRef;
   }

modules/activiti-bpmn-model/src/main/java/org/activiti/bpmn/model/ServiceTask.java

@@ -21,7 +21,7 @@ import java.util.List;
 public class ServiceTask extends Task {
 
   public static final String MAIL_TASK = "mail";
-  
+
   protected String implementation;
   protected String implementationType;
   protected String resultVariableName;
@@ -30,6 +30,7 @@ public class ServiceTask extends Task {
   protected String extensionId;
   protected List<FieldExtension> fieldExtensions = new ArrayList<FieldExtension>();
   protected List<CustomProperty> customProperties = new ArrayList<CustomProperty>();
+  protected String skipExpression;
 
   public String getImplementation() {
     return implementation;
@@ -83,12 +84,20 @@ public class ServiceTask extends Task {
     return extensionId != null && !extensionId.isEmpty();
   }
   
+  public String getSkipExpression() {
+    return skipExpression;
+  }
+
+  public void setSkipExpression(String skipExpression) {
+    this.skipExpression = skipExpression;
+  }
+
   public ServiceTask clone() {
     ServiceTask clone = new ServiceTask();
     clone.setValues(this);
     return clone;
   }
-  
+
   public void setValues(ServiceTask otherElement) {
     super.setValues(otherElement);
     setImplementation(otherElement.getImplementation());
@@ -97,14 +106,14 @@ public class ServiceTask extends Task {
     setType(otherElement.getType());
     setOperationRef(otherElement.getOperationRef());
     setExtensionId(otherElement.getExtensionId());
-    
+
     fieldExtensions = new ArrayList<FieldExtension>();
     if (otherElement.getFieldExtensions() != null && !otherElement.getFieldExtensions().isEmpty()) {
       for (FieldExtension extension : otherElement.getFieldExtensions()) {
         fieldExtensions.add(extension.clone());
       }
     }
-    
+
     customProperties = new ArrayList<CustomProperty>();
     if (otherElement.getCustomProperties() != null && !otherElement.getCustomProperties().isEmpty()) {
       for (CustomProperty property : otherElement.getCustomProperties()) {

modules/activiti-bpmn-model/src/main/java/org/activiti/bpmn/model/UserTask.java

@@ -19,7 +19,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
-
 /**
  * @author Tijs Rademakers
  */
@@ -35,7 +34,8 @@ public class UserTask extends Task {
   protected List<String> candidateGroups = new ArrayList<String>();
   protected List<FormProperty> formProperties = new ArrayList<FormProperty>();
   protected List<ActivitiListener> taskListeners = new ArrayList<ActivitiListener>();
-  
+  protected String skipExpression;
+
   protected Map<String, Set<String>> customUserIdentityLinks = new HashMap<String, Set<String>>(); 
   protected Map<String, Set<String>> customGroupIdentityLinks = new HashMap<String, Set<String>>(); 
 
@@ -135,11 +135,17 @@ public class UserTask extends Task {
 	return customGroupIdentityLinks;
   }
   
-  public void setCustomGroupIdentityLinks(
-		Map<String, Set<String>> customGroupIdentityLinks) {
-	this.customGroupIdentityLinks = customGroupIdentityLinks;
+  public void setCustomGroupIdentityLinks(Map<String, Set<String>> customGroupIdentityLinks) {
+    this.customGroupIdentityLinks = customGroupIdentityLinks;
   }
   
+  public String getSkipExpression() {
+    return skipExpression;
+  }
+  
+  public void setSkipExpression(String skipExpression) {
+    this.skipExpression = skipExpression;
+  }
   public UserTask clone() {
     UserTask clone = new UserTask();
     clone.setValues(this);

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/BpmnActivityBehavior.java

@@ -14,9 +14,11 @@
 package org.activiti.engine.impl.bpmn.behavior;
 
 import org.activiti.engine.ActivitiException;
+import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.delegate.event.ActivitiEventType;
 import org.activiti.engine.delegate.event.impl.ActivitiEventBuilder;
 import org.activiti.engine.impl.Condition;
+import org.activiti.engine.impl.bpmn.helper.SkipExpressionUtil;
 import org.activiti.engine.impl.bpmn.parser.BpmnParse;
 import org.activiti.engine.impl.context.Context;
 import org.activiti.engine.impl.persistence.entity.ExecutionEntity;
@@ -118,12 +120,19 @@ public class BpmnActivityBehavior implements Serializable {
 
     List<PvmTransition> outgoingTransitions = execution.getActivity().getOutgoingTransitions();
     for (PvmTransition outgoingTransition : outgoingTransitions) {
-      if (defaultSequenceFlow == null || !outgoingTransition.getId().equals(defaultSequenceFlow)) {
-        Condition condition = (Condition) outgoingTransition.getProperty(BpmnParse.PROPERTYNAME_CONDITION);
-        if (condition == null || !checkConditions || condition.evaluate(execution)) {
-          transitionsToTake.add(outgoingTransition);
+      Expression skipExpression = outgoingTransition.getSkipExpression();
+      
+      if(! SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression)) {
+        if (defaultSequenceFlow == null || !outgoingTransition.getId().equals(defaultSequenceFlow)) {
+          Condition condition = (Condition) outgoingTransition.getProperty(BpmnParse.PROPERTYNAME_CONDITION);
+          if (condition == null || !checkConditions || condition.evaluate(execution)) {
+            transitionsToTake.add(outgoingTransition);
+          }
         }
       }
+      else if(SkipExpressionUtil.skipFlowElement(execution, skipExpression)){
+        transitionsToTake.add(outgoingTransition);
+      }
     }
 
     if (transitionsToTake.size() == 1) {

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/ServiceTaskDelegateExpressionActivityBehavior.java

@@ -20,6 +20,7 @@ import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.delegate.JavaDelegate;
 import org.activiti.engine.impl.bpmn.helper.ClassDelegate;
 import org.activiti.engine.impl.bpmn.helper.ErrorPropagation;
+import org.activiti.engine.impl.bpmn.helper.SkipExpressionUtil;
 import org.activiti.engine.impl.bpmn.parser.FieldDeclaration;
 import org.activiti.engine.impl.context.Context;
 import org.activiti.engine.impl.delegate.ActivityBehaviorInvocation;
@@ -41,10 +42,12 @@ import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior;
 public class ServiceTaskDelegateExpressionActivityBehavior extends TaskActivityBehavior {
   
   protected Expression expression;
+  protected Expression skipExpression;
   private final List<FieldDeclaration> fieldDeclarations;
-  
-  public ServiceTaskDelegateExpressionActivityBehavior(Expression expression, List<FieldDeclaration> fieldDeclarations) {
+
+  public ServiceTaskDelegateExpressionActivityBehavior(Expression expression, Expression skipExpression, List<FieldDeclaration> fieldDeclarations) {
     this.expression = expression;
+    this.skipExpression = skipExpression;
     this.fieldDeclarations = fieldDeclarations;
   }
 
@@ -60,27 +63,29 @@ public class ServiceTaskDelegateExpressionActivityBehavior extends TaskActivityB
 	public void execute(ActivityExecution execution) throws Exception {
 
     try {
+      boolean isSkipExpressionEnabled = SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression); 
+      if (!isSkipExpressionEnabled || 
+              (isSkipExpressionEnabled && !SkipExpressionUtil.skipFlowElement(execution, skipExpression))) {
+        // Note: we can't cache the result of the expression, because the
+        // execution can change: eg.
+        // delegateExpression='${mySpringBeanFactory.randomSpringBean()}'
+        Object delegate = expression.getValue(execution);
+        ClassDelegate.applyFieldDeclaration(fieldDeclarations, delegate);
 
-      // Note: we can't cache the result of the expression, because the
-      // execution can change: eg. delegateExpression='${mySpringBeanFactory.randomSpringBean()}'
-      Object delegate = expression.getValue(execution);
-      ClassDelegate.applyFieldDeclaration(fieldDeclarations, delegate);
+        if (delegate instanceof ActivityBehavior) {
+          Context.getProcessEngineConfiguration().getDelegateInterceptor()
+                  .handleInvocation(new ActivityBehaviorInvocation((ActivityBehavior) delegate, execution));
 
-      if (delegate instanceof ActivityBehavior) {
-        Context.getProcessEngineConfiguration()
-          .getDelegateInterceptor()
-          .handleInvocation(new ActivityBehaviorInvocation((ActivityBehavior) delegate, execution));
-
-      } else if (delegate instanceof JavaDelegate) {
-        Context.getProcessEngineConfiguration()
-          .getDelegateInterceptor()
-          .handleInvocation(new JavaDelegateInvocation((JavaDelegate) delegate, execution));
-        leave(execution);
+        } else if (delegate instanceof JavaDelegate) {
+          Context.getProcessEngineConfiguration().getDelegateInterceptor().handleInvocation(new JavaDelegateInvocation((JavaDelegate) delegate, execution));
+          leave(execution);
 
+        } else {
+          throw new ActivitiIllegalArgumentException("Delegate expression " + expression + " did neither resolve to an implementation of "
+                  + ActivityBehavior.class + " nor " + JavaDelegate.class);
+        }
       } else {
-        throw new ActivitiIllegalArgumentException("Delegate expression " + expression
-                + " did neither resolve to an implementation of " + ActivityBehavior.class
-                + " nor " + JavaDelegate.class);
+        leave(execution);
       }
     } catch (Exception exc) {
 

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/ServiceTaskExpressionActivityBehavior.java

@@ -13,15 +13,16 @@
 
 package org.activiti.engine.impl.bpmn.behavior;
 
+import org.activiti.engine.ActivitiIllegalArgumentException;
 import org.activiti.engine.delegate.BpmnError;
 import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.impl.bpmn.helper.ErrorPropagation;
+import org.activiti.engine.impl.bpmn.helper.SkipExpressionUtil;
 import org.activiti.engine.impl.pvm.delegate.ActivityExecution;
 
-
 /**
- * ActivityBehavior that evaluates an expression when executed. Optionally, it sets the result 
- * of the expression as a variable on the execution.
+ * ActivityBehavior that evaluates an expression when executed. Optionally, it
+ * sets the result of the expression as a variable on the execution.
  * 
  * @author Tom Baeyens
  * @author Christian Stettler
@@ -32,21 +33,28 @@ import org.activiti.engine.impl.pvm.delegate.ActivityExecution;
 public class ServiceTaskExpressionActivityBehavior extends TaskActivityBehavior {
 
   protected Expression expression;
+  protected Expression skipExpression;
   protected String resultVariable;
 
-  public ServiceTaskExpressionActivityBehavior(Expression expression, String resultVariable) {
+  public ServiceTaskExpressionActivityBehavior(Expression expression, Expression skipExpression, String resultVariable) {
     this.expression = expression;
+    this.skipExpression = skipExpression;
     this.resultVariable = resultVariable;
   }
 
   public void execute(ActivityExecution execution) throws Exception {
-	Object value = null;
-	try {
-		value = expression.getValue(execution);
-		if (resultVariable != null) {
-		    execution.setVariable(resultVariable, value);
-		}
-		leave(execution);
+    Object value = null;
+    try {
+      boolean isSkipExpressionEnabled = SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression);
+      if (!isSkipExpressionEnabled || 
+              (isSkipExpressionEnabled && !SkipExpressionUtil.skipFlowElement(execution, skipExpression))) {
+        value = expression.getValue(execution);
+        if (resultVariable != null) {
+          execution.setVariable(resultVariable, value);
+        }
+      }
+
+      leave(execution);
     } catch (Exception exc) {
 
       Throwable cause = exc;

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/UserTaskActivityBehavior.java

@@ -26,6 +26,7 @@ import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.delegate.TaskListener;
 import org.activiti.engine.delegate.event.ActivitiEventType;
 import org.activiti.engine.delegate.event.impl.ActivitiEventBuilder;
+import org.activiti.engine.impl.bpmn.helper.SkipExpressionUtil;
 import org.activiti.engine.impl.calendar.BusinessCalendar;
 import org.activiti.engine.impl.calendar.DueDateBusinessCalendar;
 import org.activiti.engine.impl.context.Context;
@@ -131,6 +132,12 @@ public class UserTaskActivityBehavior extends TaskActivityBehavior {
     }
 
     task.fireEvent(TaskListener.EVENTNAME_CREATE);
+
+    Expression skipExpression = taskDefinition.getSkipExpression();
+    if (SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression) &&
+        SkipExpressionUtil.skipFlowElement(execution, skipExpression)) {
+      leave(execution);
+    }
   }
 
   public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/helper/ClassDelegate.java

@@ -22,6 +22,7 @@ import org.activiti.engine.ActivitiException;
 import org.activiti.engine.ActivitiIllegalArgumentException;
 import org.activiti.engine.delegate.BpmnError;
 import org.activiti.engine.delegate.DelegateExecution;
+import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.delegate.DelegateTask;
 import org.activiti.engine.delegate.ExecutionListener;
 import org.activiti.engine.delegate.JavaDelegate;
@@ -54,14 +55,16 @@ public class ClassDelegate extends AbstractBpmnActivityBehavior implements TaskL
   protected ExecutionListener executionListenerInstance;
   protected TaskListener taskListenerInstance;
   protected ActivityBehavior activityBehaviorInstance;
-  
-  public ClassDelegate(String className, List<FieldDeclaration> fieldDeclarations) {
+  protected Expression skipExpression;
+
+  public ClassDelegate(String className, List<FieldDeclaration> fieldDeclarations, Expression skipExpression) {
     this.className = className;
     this.fieldDeclarations = fieldDeclarations;
+    this.skipExpression = skipExpression;
   }
-  
-  public ClassDelegate(Class<?> clazz, List<FieldDeclaration> fieldDeclarations) {
-    this(clazz.getName(), fieldDeclarations);
+
+  public ClassDelegate(Class< ? > clazz, List<FieldDeclaration> fieldDeclarations, Expression skipExpression) {
+    this(clazz.getName(), fieldDeclarations, skipExpression);
   }
 
   // Execution listener
@@ -110,13 +113,17 @@ public class ClassDelegate extends AbstractBpmnActivityBehavior implements TaskL
 
   // Activity Behavior
   public void execute(ActivityExecution execution) throws Exception {
-    if (activityBehaviorInstance == null) {
-      activityBehaviorInstance = getActivityBehaviorInstance(execution);
-    }
-    try {
-      activityBehaviorInstance.execute(execution);
-    } catch (BpmnError error) {
-      ErrorPropagation.propagateError(error, execution);
+    boolean isSkipExpressionEnabled = SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression);
+    if (!isSkipExpressionEnabled || 
+            (isSkipExpressionEnabled && !SkipExpressionUtil.skipFlowElement(execution, skipExpression))) {
+      if (activityBehaviorInstance == null) {
+        activityBehaviorInstance = getActivityBehaviorInstance(execution);
+      }
+      try {
+        activityBehaviorInstance.execute(execution);
+      } catch (BpmnError error) {
+        ErrorPropagation.propagateError(error, execution);
+      }
     }
   }
 

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/helper/SkipExpressionUtil.java

+package org.activiti.engine.impl.bpmn.helper;
+
+import org.activiti.engine.ActivitiIllegalArgumentException;
+import org.activiti.engine.delegate.Expression;
+import org.activiti.engine.impl.pvm.delegate.ActivityExecution;
+
+
+public class SkipExpressionUtil {
+  public static boolean isSkipExpressionEnabled(ActivityExecution execution, Expression skipExpression)
+  {
+    if(null == skipExpression)
+    {
+      return false;
+    }
+    
+    final String skipExpressionEnabledVariable = "_ACTIVITI_SKIP_EXPRESSION_ENABLED";
+    Object isSkipExpressionEnabled = execution.getVariable(skipExpressionEnabledVariable);
+    if(null == isSkipExpressionEnabled)
+    {
+      return false;
+    }
+    else if(isSkipExpressionEnabled instanceof Boolean)
+    {
+      return ((Boolean)isSkipExpressionEnabled).booleanValue();
+    }
+    else
+    {
+      throw new ActivitiIllegalArgumentException(skipExpressionEnabledVariable + " variable does not resolve to a boolean. " + isSkipExpressionEnabled);
+    } 
+  }
+  
+  public static boolean skipFlowElement(ActivityExecution execution, Expression skipExpression)
+  {
+    Object value = skipExpression.getValue(execution);
+    if(value instanceof Boolean)
+    {
+      return ((Boolean)value).booleanValue();
+    }
+    else
+    {
+      throw new ActivitiIllegalArgumentException("Skip expression does not resolve to a boolean: " + skipExpression.getExpressionText());
+    }
+  }
+}

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/parser/factory/DefaultActivityBehaviorFactory.java

@@ -89,9 +89,9 @@ import org.activiti.engine.impl.task.TaskDefinition;
 import org.apache.commons.lang3.StringUtils;
 
 /**
- * Default implementation of the {@link ActivityBehaviorFactory}. 
- * Used when no custom {@link ActivityBehaviorFactory} is injected on 
- * the {@link ProcessEngineConfigurationImpl}.
+ * Default implementation of the {@link ActivityBehaviorFactory}. Used when no
+ * custom {@link ActivityBehaviorFactory} is injected on the
+ * {@link ProcessEngineConfigurationImpl}.
  * 
  * @author Joram Barrez
  */
@@ -128,17 +128,43 @@ public class DefaultActivityBehaviorFactory extends AbstractBehaviorFactory impl
   // Service task
   
   public ClassDelegate createClassDelegateServiceTask(ServiceTask serviceTask) {
-    return new ClassDelegate(serviceTask.getImplementation(), createFieldDeclarations(serviceTask.getFieldExtensions()));
+    Expression skipExpression;
+    if(StringUtils.isNotEmpty(serviceTask.getSkipExpression()))
+    {
+      skipExpression = expressionManager.createExpression(serviceTask.getSkipExpression());
+    }
+    else
+    {
+      skipExpression = null;
+    }
+    return new ClassDelegate(serviceTask.getImplementation(), createFieldDeclarations(serviceTask.getFieldExtensions()), skipExpression);
   }
   
   public ServiceTaskDelegateExpressionActivityBehavior createServiceTaskDelegateExpressionActivityBehavior(ServiceTask serviceTask) {
     Expression delegateExpression = expressionManager.createExpression(serviceTask.getImplementation());
-    return new ServiceTaskDelegateExpressionActivityBehavior(delegateExpression, createFieldDeclarations(serviceTask.getFieldExtensions()));
+    Expression skipExpression;
+    if(StringUtils.isNotEmpty(serviceTask.getSkipExpression()))
+    {
+      skipExpression = expressionManager.createExpression(serviceTask.getSkipExpression());
+    }
+    else
+    {
+      skipExpression = null;
+    }
+    return new ServiceTaskDelegateExpressionActivityBehavior(delegateExpression, skipExpression, createFieldDeclarations(serviceTask.getFieldExtensions()));
   }
   
   public ServiceTaskExpressionActivityBehavior createServiceTaskExpressionActivityBehavior(ServiceTask serviceTask) {
     Expression expression = expressionManager.createExpression(serviceTask.getImplementation());
-    return new ServiceTaskExpressionActivityBehavior(expression, serviceTask.getResultVariableName());
+    Expression skipExpression;
+    if (StringUtils.isNotEmpty(serviceTask.getSkipExpression())) {
+      skipExpression = expressionManager.createExpression(serviceTask.getSkipExpression());
+    }
+    else
+    {
+      skipExpression = null;
+    }
+    return new ServiceTaskExpressionActivityBehavior(expression, skipExpression, serviceTask.getResultVariableName());
   }
   
   public WebServiceActivityBehavior createWebServiceActivityBehavior(ServiceTask serviceTask) {

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/parser/factory/DefaultListenerFactory.java

@@ -65,7 +65,7 @@ public class DefaultListenerFactory extends AbstractBehaviorFactory implements L
 	}
 
   public TaskListener createClassDelegateTaskListener(ActivitiListener activitiListener) {
-    return new ClassDelegate(activitiListener.getImplementation(), createFieldDeclarations(activitiListener.getFieldExtensions()));
+    return new ClassDelegate(activitiListener.getImplementation(), createFieldDeclarations(activitiListener.getFieldExtensions()), null);
   }
   
   public TaskListener createExpressionTaskListener(ActivitiListener activitiListener) {
@@ -78,7 +78,7 @@ public class DefaultListenerFactory extends AbstractBehaviorFactory implements L
   }
 
   public ExecutionListener createClassDelegateExecutionListener(ActivitiListener activitiListener) {
-    return new ClassDelegate(activitiListener.getImplementation(), createFieldDeclarations(activitiListener.getFieldExtensions()));
+    return new ClassDelegate(activitiListener.getImplementation(), createFieldDeclarations(activitiListener.getFieldExtensions()), null);
   }
   
   public ExecutionListener createExpressionExecutionListener(ActivitiListener activitiListener) {

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/parser/handler/SequenceFlowParseHandler.java

@@ -14,8 +14,10 @@ package org.activiti.engine.impl.bpmn.parser.handler;
 
 import org.activiti.bpmn.model.BaseElement;
 import org.activiti.bpmn.model.SequenceFlow;
+import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.impl.Condition;
 import org.activiti.engine.impl.bpmn.parser.BpmnParse;
+import org.activiti.engine.impl.el.ExpressionManager;
 import org.activiti.engine.impl.el.UelExpressionCondition;
 import org.activiti.engine.impl.pvm.process.ActivityImpl;
 import org.activiti.engine.impl.pvm.process.ScopeImpl;
@@ -41,7 +43,18 @@ public class SequenceFlowParseHandler extends AbstractBpmnParseHandler<SequenceF
     ActivityImpl sourceActivity = scope.findActivity(sequenceFlow.getSourceRef());
     ActivityImpl destinationActivity = scope.findActivity(sequenceFlow.getTargetRef());
 
-    TransitionImpl transition = sourceActivity.createOutgoingTransition(sequenceFlow.getId());
+    Expression skipExpression;
+    if(StringUtils.isNotEmpty(sequenceFlow.getSkipExpression()))
+    {
+      ExpressionManager expressionManager = bpmnParse.getExpressionManager();
+      skipExpression = expressionManager.createExpression(sequenceFlow.getSkipExpression());
+    }
+    else
+    {
+      skipExpression = null;
+    }
+    
+    TransitionImpl transition = sourceActivity.createOutgoingTransition(sequenceFlow.getId(), skipExpression);
     bpmnParse.getSequenceFlows().put(sequenceFlow.getId(), transition);
     transition.setProperty("name", sequenceFlow.getName());
     transition.setProperty("documentation", sequenceFlow.getDocumentation());

modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/parser/handler/UserTaskParseHandler.java

@@ -129,6 +129,10 @@ public class UserTaskParseHandler extends AbstractActivityBpmnParseHandler<UserT
     	taskDefinition.addCustomGroupIdentityLinkExpression(customGroupIdentityLinkType, groupIdentityLinkExpression);
       }
 
+    if (StringUtils.isNotEmpty(userTask.getSkipExpression())) {
+      taskDefinition.setSkipExpression(expressionManager.createExpression(userTask.getSkipExpression()));
+    }
+    
     return taskDefinition;
   }
   

modules/activiti-engine/src/main/java/org/activiti/engine/impl/pvm/ProcessDefinitionBuilder.java

@@ -81,7 +81,7 @@ public class ProcessDefinitionBuilder {
       throw new PvmException("destinationActivityId is null");
     }
     ActivityImpl activity = getActivity();
-    transition = activity.createOutgoingTransition(transitionId);
+    transition = activity.createOutgoingTransition(transitionId, null);
     unresolvedTransitions.add(new Object[]{transition, destinationActivityId});
     processElement = transition;
     return this;

modules/activiti-engine/src/main/java/org/activiti/engine/impl/pvm/PvmTransition.java

@@ -13,6 +13,8 @@
 
 package org.activiti.engine.impl.pvm;
 
+import org.activiti.engine.delegate.Expression;
+
 
 
 /**
@@ -23,4 +25,6 @@ public interface PvmTransition extends PvmProcessElement {
   PvmActivity getSource();
 
   PvmActivity getDestination();
+  
+  Expression getSkipExpression();
 }

modules/activiti-engine/src/main/java/org/activiti/engine/impl/pvm/process/ActivityImpl.java

@@ -18,6 +18,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.impl.pvm.PvmActivity;
 import org.activiti.engine.impl.pvm.PvmException;
 import org.activiti.engine.impl.pvm.PvmTransition;
@@ -52,7 +53,7 @@ public class ActivityImpl extends ScopeImpl implements PvmActivity, HasDIBounds
   }
 
   public TransitionImpl createOutgoingTransition() {
-    return createOutgoingTransition(null);
+    return createOutgoingTransition(null, null);
   }
   public String getFailedJobRetryTimeCycleValue() {
 		return failedJobRetryTimeCycleValue;
@@ -61,8 +62,8 @@ public class ActivityImpl extends ScopeImpl implements PvmActivity, HasDIBounds
 	  this.failedJobRetryTimeCycleValue = failedJobRetryTimeCycleValue;
   }
 
-  public TransitionImpl createOutgoingTransition(String transitionId) {
-    TransitionImpl transition = new TransitionImpl(transitionId, processDefinition);
+  public TransitionImpl createOutgoingTransition(String transitionId, Expression skipExpression) {
+    TransitionImpl transition = new TransitionImpl(transitionId, skipExpression, processDefinition);
     transition.setSource(this);
     outgoingTransitions.add(transition);
     

modules/activiti-engine/src/main/java/org/activiti/engine/impl/pvm/process/TransitionImpl.java

@@ -18,6 +18,7 @@ import java.util.Collections;
 import java.util.List;
 
 import org.activiti.engine.delegate.ExecutionListener;
+import org.activiti.engine.delegate.Expression;
 import org.activiti.engine.impl.pvm.PvmTransition;
 
 
@@ -31,12 +32,14 @@ public class TransitionImpl extends ProcessElementImpl implements PvmTransition
   protected ActivityImpl source;
   protected ActivityImpl destination;
   protected List<ExecutionListener> executionListeners;
+  protected Expression skipExpression;
   
   /** Graphical information: a list of waypoints: x1, y1, x2, y2, x3, y3, .. */
   protected List<Integer> waypoints = new ArrayList<Integer>();
 
-  public TransitionImpl(String id, ProcessDefinitionImpl processDefinition) {
+  public TransitionImpl(String id, Expression skipExpression, ProcessDefinitionImpl processDefinition) {
     super(id, processDefinition);
+    this.skipExpression = skipExpression;
   }
 
   public ActivityImpl getSource() {
@@ -88,5 +91,12 @@ public class TransitionImpl extends ProcessElementImpl implements PvmTransition
   public void setWaypoints(List<Integer> waypoints) {
     this.waypoints = waypoints;
   }
+
+  public Expression getSkipExpression() {
+    return skipExpression;
+  }
   
+  public void setSkipExpression(Expression skipExpression) {
+    this.skipExpression = skipExpression;
+  }
 }

modules/activiti-engine/src/main/java/org/activiti/engine/impl/task/TaskDefinition.java

@@ -46,7 +46,8 @@ public class TaskDefinition implements Serializable {
   protected Expression priorityExpression;
   protected Expression categoryExpression;
   protected Map<String, Set<Expression>> customUserIdentityLinkExpressions = new HashMap<String, Set<Expression>>(); 
-  protected Map<String, Set<Expression>> customGroupIdentityLinkExpressions = new HashMap<String, Set<Expression>>(); 
+  protected Map<String, Set<Expression>> customGroupIdentityLinkExpressions = new HashMap<String, Set<Expression>>();
+  protected Expression skipExpression;
   
   // form fields
   protected TaskFormHandler taskFormHandler;
@@ -204,4 +205,12 @@ public class TaskDefinition implements Serializable {
     }
   }
   
+  public Expression getSkipExpression() {
+    return skipExpression;
+  }
+
+  
+  public void setSkipExpression(Expression skipExpression) {
+    this.skipExpression = skipExpression;
+  }
 }

modules/activiti-engine/src/main/java/org/activiti/engine/test/TestActivityBehaviorFactory.java

@@ -165,7 +165,7 @@ public class TestActivityBehaviorFactory extends AbstractBehaviorFactory impleme
 		} else if (serviceTask.getImplementation() != null && mockedClassDelegatesMapping.containsKey(serviceTask.getImplementation())) {
 				
 			return new ClassDelegate(mockedClassDelegatesMapping.get(serviceTask.getImplementation()),
-					createFieldDeclarations(serviceTask.getFieldExtensions()));
+					createFieldDeclarations(serviceTask.getFieldExtensions()), null);
 			
 		}
 		
@@ -176,7 +176,7 @@ public class TestActivityBehaviorFactory extends AbstractBehaviorFactory impleme
 	  List<FieldDeclaration> fieldDeclarations = new ArrayList<FieldDeclaration>();
 	  fieldDeclarations.add(new FieldDeclaration("name", 
 	  		Expression.class.getName(), new FixedValue(serviceTask.getImplementation())));
-	  return new ClassDelegate(NoOpServiceTask.class, fieldDeclarations);
+	  return new ClassDelegate(NoOpServiceTask.class, fieldDeclarations, null);
   }
 
 	@Override

modules/activiti-engine/src/test/java/org/activiti/engine/test/bpmn/sequenceflow/ConditionalSequenceFlowTest.java

@@ -13,6 +13,7 @@
 
 package org.activiti.engine.test.bpmn.sequenceflow;
 
+import java.util.HashMap;
 import java.util.Map;
 
 import org.activiti.engine.impl.test.PluggableActivitiTestCase;
@@ -39,4 +40,21 @@ public class ConditionalSequenceFlowTest extends PluggableActivitiTestCase {
     
     assertEquals("task right", task.getName());
   }
+  
+  @Deployment
+  public void testSkipExpression() {
+    Map<String, Object> variables = new HashMap<String,Object>();
+    variables.put("input", "right");
+    variables.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables.put("skipLeft", true);
+    variables.put("skipRight", false);
+    ProcessInstance pi = runtimeService.startProcessInstanceByKey("testSkipExpression", variables);
+    
+    Task task = taskService
+      .createTaskQuery()
+      .processInstanceId(pi.getId())
+      .singleResult();
+    
+    assertEquals("task left", task.getName());
+  }
 }
\ No newline at end of file

modules/activiti-engine/src/test/java/org/activiti/examples/bpmn/servicetask/ExpressionServiceTaskTest.java

@@ -20,6 +20,29 @@ public class ExpressionServiceTaskTest extends PluggableActivitiTestCase {
     assertEquals("ok", runtimeService.getVariable(pi.getId(), "result"));
   }
 
+  @Deployment
+  public void testSetServiceResultToProcessVariablesWithSkipExpression() {
+    Map<String,Object> variables = new HashMap<String, Object>();
+    variables.put("bean", new ValueBean("ok"));
+    variables.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables.put("skip", false);
+    ProcessInstance pi = runtimeService.startProcessInstanceByKey("setServiceResultToProcessVariablesWithSkipExpression", variables);
+    assertEquals("ok", runtimeService.getVariable(pi.getId(), "result"));
+    
+    Map<String,Object> variables2 = new HashMap<String, Object>();
+    variables2.put("bean", new ValueBean("ok"));
+    variables2.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables2.put("skip", true);
+    ProcessInstance pi2 = runtimeService.startProcessInstanceByKey("setServiceResultToProcessVariablesWithSkipExpression", variables2);
+    assertEquals(null, runtimeService.getVariable(pi2.getId(), "result"));
+    
+    Map<String,Object> variables3 = new HashMap<String, Object>();
+    variables3.put("bean", new ValueBean("ok"));
+    variables3.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    ProcessInstance pi3 = runtimeService.startProcessInstanceByKey("setServiceResultToProcessVariablesWithSkipExpression", variables2);
+    assertEquals(null, runtimeService.getVariable(pi3.getId(), "result"));
+  }
+  
   @Deployment
   public void testBackwardsCompatibleExpression() {
     Map<String,Object> variables = new HashMap<String, Object>();

modules/activiti-engine/src/test/java/org/activiti/examples/bpmn/servicetask/JavaServiceTaskTest.java

@@ -71,6 +71,40 @@ public class JavaServiceTaskTest extends PluggableActivitiTestCase {
     assertEquals("elam :si redneg ruoY", runtimeService.getVariable(execution.getId(), "var1"));
   }
   
+  @Deployment
+  public void testExpressionFieldInjectionWithSkipExpression() {
+    Map<String, Object> vars = new HashMap<String, Object>();
+    vars.put("name", "kermit");
+    vars.put("gender", "male");
+    vars.put("genderBean", new GenderBean());
+    vars.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    vars.put("skip", false);
+    
+    ProcessInstance pi = runtimeService.startProcessInstanceByKey("expressionFieldInjectionWithSkipExpression", vars);
+    Execution execution = runtimeService.createExecutionQuery()
+      .processInstanceId(pi.getId())
+      .activityId("waitState")
+      .singleResult();
+    
+    assertEquals("timrek .rM olleH", runtimeService.getVariable(execution.getId(), "var2"));
+    assertEquals("elam :si redneg ruoY", runtimeService.getVariable(execution.getId(), "var1"));
+    
+    Map<String, Object> vars2 = new HashMap<String, Object>();
+    vars2.put("name", "kermit");
+    vars2.put("gender", "male");
+    vars2.put("genderBean", new GenderBean());
+    vars2.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    vars2.put("skip", true);
+    
+    ProcessInstance pi2 = runtimeService.startProcessInstanceByKey("expressionFieldInjectionWithSkipExpression", vars2);
+    Execution execution2 = runtimeService.createExecutionQuery()
+      .processInstanceId(pi2.getId())
+      .activityId("waitState")
+      .singleResult();
+    
+    assertEquals(null, execution2);
+  }
+  
   @Deployment
   public void testUnexistingClassDelegation() {
     try {

modules/activiti-engine/src/test/java/org/activiti/examples/bpmn/servicetask/MethodExpressionServiceTaskTest.java

@@ -22,4 +22,24 @@ public class MethodExpressionServiceTaskTest extends PluggableActivitiTestCase {
     assertEquals("ok", runtimeService.getVariable(pi.getId(), "result"));
   }
 
+  @Deployment
+  public void testSetServiceResultToProcessVariablesWithSkipExpression() {
+    Map<String,Object> variables = new HashMap<String, Object>();
+    variables.put("okReturningService", new OkReturningService());
+    variables.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", false);
+
+    ProcessInstance pi = runtimeService.startProcessInstanceByKey("setServiceResultToProcessVariablesWithSkipExpression", variables);
+
+    assertEquals("ok", runtimeService.getVariable(pi.getId(), "result"));
+    
+    Map<String,Object> variables2 = new HashMap<String, Object>();
+    variables2.put("okReturningService", new OkReturningService());
+    variables2.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables2.put("skip", true);
+
+    ProcessInstance pi2 = runtimeService.startProcessInstanceByKey("setServiceResultToProcessVariablesWithSkipExpression", variables2);
+
+    assertEquals(null, runtimeService.getVariable(pi2.getId(), "result"));
+    
+  }  
 }
\ No newline at end of file

modules/activiti-engine/src/test/java/org/activiti/examples/bpmn/usertask/SkipExpressionUserTaskTest.java

+package org.activiti.examples.bpmn.usertask;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.activiti.engine.impl.test.PluggableActivitiTestCase;
+import org.activiti.engine.runtime.ProcessInstance;
+import org.activiti.engine.task.Task;
+import org.activiti.engine.test.Deployment;
+
+public class SkipExpressionUserTaskTest extends PluggableActivitiTestCase {
+
+  @Deployment
+  public void test() {
+    ProcessInstance pi = runtimeService.startProcessInstanceByKey("skipExpressionUserTask");
+    List<Task> tasks = taskService.createTaskQuery().list();
+    assertEquals(1, tasks.size());
+    taskService.complete(tasks.get(0).getId());
+    assertEquals(0, taskService.createTaskQuery().list().size());
+
+    Map<String, Object> variables2 = new HashMap<String, Object>();
+    variables2.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables2.put("skip", false);
+    ProcessInstance pi2 = runtimeService.startProcessInstanceByKey("skipExpressionUserTask", variables2);
+    List<Task> tasks2 = taskService.createTaskQuery().list();
+    assertEquals(1, tasks2.size());
+    taskService.complete(tasks2.get(0).getId());
+    assertEquals(0, taskService.createTaskQuery().list().size());
+
+    Map<String, Object> variables3 = new HashMap<String, Object>();
+    variables3.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
+    variables3.put("skip", true);
+    ProcessInstance pi3 = runtimeService.startProcessInstanceByKey("skipExpressionUserTask", variables3);
+    List<Task> tasks3 = taskService.createTaskQuery().list();
+    assertEquals(0, tasks3.size());
+  }
+}

modules/activiti-engine/src/test/resources/org/activiti/engine/test/bpmn/sequenceflow/ConditionalSequenceFlowTest.testSkipExpression.bpmn20.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<definitions id="definitions" 
+  xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xmlns:activiti="http://activiti.org/bpmn"
+  targetNamespace="Examples">
+  
+  <process id="testSkipExpression">
+  
+    <startEvent id="theStart" />
+    
+    <sequenceFlow id="flow1" sourceRef="theStart" targetRef="task1" activiti:skipExpression="${skipLeft}">
+      <conditionExpression xsi:type="tFormalExpression">
+         <![CDATA[${input == 'left'}]]>
+      </conditionExpression>
+    </sequenceFlow>
+    
+    <sequenceFlow id="flow2" sourceRef="theStart" targetRef="task2" activiti:skipExpression="${skipRight}">
+      <conditionExpression xsi:type="tFormalExpression">
+         <![CDATA[${input == 'right'}]]>
+      </conditionExpression>
+    </sequenceFlow>
+    
+    <userTask id="task1" name="task left" />
+    
+    <userTask id="task2" name="task right" />
+    
+  </process>
+
+</definitions>
\ No newline at end of file

modules/activiti-engine/src/test/resources/org/activiti/examples/bpmn/servicetask/ExpressionServiceTaskTest.testSetServiceResultToProcessVariablesWithSkipExpression.bpmn20.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<definitions id="definitions"
+             xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+             xmlns:activiti="http://activiti.org/bpmn"
+             targetNamespace="Examples">
+
+    <process id="setServiceResultToProcessVariablesWithSkipExpression">
+
+        <startEvent id="theStart"/>
+
+        <sequenceFlow sourceRef="theStart"
+                      targetRef="valueExpressionServiceWithResultVariableNameSet"/>
+
+        <serviceTask id="valueExpressionServiceWithResultVariableNameSet"
+                     activiti:resultVariable="result"
+                     activiti:expression="#{bean.value}"
+                     activiti:skipExpression="${execution.getVariable('skip')}"/>
+
+        <sequenceFlow sourceRef="valueExpressionServiceWithResultVariableNameSet"
+                      targetRef="valueExpressionServiceWithoutResultVariableNameSet"/>
+
+        <serviceTask id="valueExpressionServiceWithoutResultVariableNameSet"
+                     activiti:expression="#{bean.value}"/>
+
+        <sequenceFlow sourceRef="valueExpressionServiceWithoutResultVariableNameSet"
+                      targetRef="waitState"/>
+
+        <userTask id="waitState"/>
+
+        <sequenceFlow sourceRef="waitState" targetRef="theEnd"/>
+
+        <endEvent id="theEnd"/>
+
+    </process>
+
+</definitions>

modules/activiti-engine/src/test/resources/org/activiti/examples/bpmn/servicetask/JavaServiceTaskTest.testExpressionFieldInjectionWithSkipExpression.bpmn20.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<definitions id="definitions" 
+  xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+  xmlns:activiti="http://activiti.org/bpmn"
+  targetNamespace="Examples">
+  
+  <process id="expressionFieldInjectionWithSkipExpression">
+  
+    <startEvent id="theStart" />
+    
+    <sequenceFlow id="flow1" sourceRef="theStart" targetRef="javaService" />
+    
+    <serviceTask id="javaService" 
+                 name="Java service invocation" 
+                 activiti:class="org.activiti.examples.bpmn.servicetask.ReverseStringsFieldInjected"
+                 activiti:skipExpression="${execution.getVariable('skip')}">
+      <extensionElements>
+        <activiti:field name="text1">
+          <activiti:expression>${genderBean.getGenderString(gender)}</activiti:expression>
+        </activiti:field>
+        <activiti:field name="text2">
+          <activiti:expression>Hello ${gender == 'male' ? 'Mr.' : 'Mrs.'} ${name}</activiti:expression>
+        </activiti:field>
+      </extensionElements>             
+    </serviceTask>
+    
+    <sequenceFlow id="flow2" sourceRef="javaService" targetRef="waitState" />
+    
+    <receiveTask id="waitState" />
+    
+    <sequenceFlow id="flow3" sourceRef="waitState" targetRef="theEnd" />
+    
+    <endEvent id="theEnd" />
+    
+  </process>
+
+</definitions>
\ No newline at end of file

modules/activiti-engine/src/test/resources/org/activiti/examples/bpmn/servicetask/MethodExpressionServiceTaskTest.testSetServiceResultToProcessVariablesWithSkipExpression.bpmn20.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<definitions id="definitions"
+             xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+             xmlns:activiti="http://activiti.org/bpmn"
+             targetNamespace="Examples">
+
+    <process id="setServiceResultToProcessVariablesWithSkipExpression">
+
+        <startEvent id="theStart"/>
+
+        <sequenceFlow sourceRef="theStart"
+                      targetRef="methodExpressionServiceWithResultVariableNameSet"/>
+
+        <serviceTask id="methodExpressionServiceWithResultVariableNameSet"
+                     activiti:resultVariable="result"
+                     activiti:expression="#{okReturningService.invoke()}"
+                     activiti:skipExpression="${skip}"/>
+
+        <sequenceFlow sourceRef="methodExpressionServiceWithResultVariableNameSet"
+                      targetRef="methodExpressionServiceWithoutResultVariableNameSet"/>
+
+        <serviceTask id="methodExpressionServiceWithoutResultVariableNameSet"
+                     activiti:expression="#{okReturningService.invoke()}"/>
+
+        <sequenceFlow sourceRef="methodExpressionServiceWithoutResultVariableNameSet"
+                      targetRef="waitState"/>
+
+        <userTask id="waitState"/>
+
+        <sequenceFlow sourceRef="waitState" targetRef="theEnd"/>
+
+        <endEvent id="theEnd"/>
+
+    </process>
+
+</definitions>

modules/activiti-engine/src/test/resources/org/activiti/examples/bpmn/usertask/SkipExpressionUserTaskTest.test.bpmn20.xml

+<definitions 
+  xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+  xmlns:activiti="http://activiti.org/bpmn"
+  targetNamespace="Examples">
+  
+  <process id="skipExpressionUserTask">
+    <startEvent id="theStart" name="Start Event"/>
+    <sequenceFlow sourceRef="theStart" targetRef="userTask1" />
+    <userTask id="userTask1" name="Task1" activiti:skipExpression="${execution.getVariable('skip')}"/> 
+    <sequenceFlow sourceRef="userTask1" targetRef="theEnd" />
+    <endEvent id="theEnd" name="End Event"/>
+  </process>
+</definitions>
\ No newline at end of file