add stop condition to process-flow engine that can be set dynamically by tasks

12 files changed, 334 insertions, 82 deletions

diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ExecutionContextImpl.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ExecutionContextImpl.java
index 88a95795..3cd696df 100644
--- a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ExecutionContextImpl.java
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ExecutionContextImpl.java
@@ -44,9 +44,10 @@ public class ExecutionContextImpl implements ExecutionContext {
 
 	private static final long serialVersionUID = 1L;
 
-	private Map<String, Serializable> ctxData = Collections.synchronizedMap(new HashMap<String, Serializable>());
+	private final Map<String, Serializable> ctxData = Collections.synchronizedMap(new HashMap<String, Serializable>());
 
 	private String processInstanceId;
+	private boolean markedAsCancelled = false;
 
 	/**
 	 * Creates a new instance.
@@ -93,7 +94,7 @@ public class ExecutionContextImpl implements ExecutionContext {
 
 	@Override
 	public String toString() {
-		StringBuilder builder = new StringBuilder();
+		final StringBuilder builder = new StringBuilder();
 		builder.append("ExecutionContextImpl [");
 		builder.append("id=").append(processInstanceId);
 		builder.append(", variables=");
@@ -102,4 +103,15 @@ public class ExecutionContextImpl implements ExecutionContext {
 		return builder.toString();
 	}
 
+	@Override
+	public boolean isProcessCancelled() {
+		return markedAsCancelled;
+	}
+
+	@Override
+	public void setCanceleProcessFlag() {
+		markedAsCancelled = true; 
+		
+	}
+
 }
diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessEngineImpl.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessEngineImpl.java
index b6b42850..53f50e1f 100644
--- a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessEngineImpl.java
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessEngineImpl.java
@@ -64,14 +64,14 @@ import at.gv.egiz.eaaf.core.impl.idp.process.model.Transition;
  */
 public class ProcessEngineImpl implements ProcessEngine {
  
-	private Logger log = LoggerFactory.getLogger(getClass());
+	private final Logger log = LoggerFactory.getLogger(getClass());
 
 	@Autowired ProcessInstanceStoreDAO piStoreDao;
 	@Autowired ApplicationContext context;
 	
-	private ProcessDefinitionParser pdp = new ProcessDefinitionParser();
+	private final ProcessDefinitionParser pdp = new ProcessDefinitionParser();
 
-	private Map<String, ProcessDefinition> processDefinitions = new ConcurrentHashMap<String, ProcessDefinition>();
+	private final Map<String, ProcessDefinition> processDefinitions = new ConcurrentHashMap<String, ProcessDefinition>();
 
 	private final static String MDC_CTX_PI_NAME = "processInstanceId";
 	private final static String MDC_CTX_TASK_NAME = "taskId";
@@ -86,7 +86,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 
 	@Override
 	public String registerProcessDefinition(InputStream processDefinitionInputStream) throws ProcessDefinitionParserException{
-		ProcessDefinition pd = pdp.parse(processDefinitionInputStream);
+		final ProcessDefinition pd = pdp.parse(processDefinitionInputStream);
 		
 		postValidationOfProcessDefintion(pd);
 		
@@ -104,7 +104,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 	 */
 	public void setProcessDefinitions(Iterable<ProcessDefinition> processDefinitions) {
 		this.processDefinitions.clear();
-		for (ProcessDefinition pd : processDefinitions) {
+		for (final ProcessDefinition pd : processDefinitions) {
 			if (this.processDefinitions.containsKey(pd.getId())) {
 				throw new IllegalArgumentException("Duplicate process definition identifier '" + pd.getId() + "'.");
 			}
@@ -125,18 +125,18 @@ public class ProcessEngineImpl implements ProcessEngine {
 	@Override
 	public String createProcessInstance(String processDefinitionId, ExecutionContext executionContext) throws ProcessExecutionException {
 		// look for respective process definition
-		ProcessDefinition pd = processDefinitions.get(processDefinitionId);
+		final ProcessDefinition pd = processDefinitions.get(processDefinitionId);
 		if (pd == null) {
 			throw new ProcessExecutionException("Unable to find process definition for process '" + processDefinitionId + "'.");
 		}
 		// create and keep process instance
-		ProcessInstance pi = new ProcessInstance(pd, executionContext);
+		final ProcessInstance pi = new ProcessInstance(pd, executionContext);
 		log.info("Creating process instance from process definition '{}': {}", processDefinitionId, pi.getId());
 
 		try {
 			saveOrUpdateProcessInstance(pi);
 			
-		} catch (EAAFException e) {
+		} catch (final EAAFException e) {
 			throw new ProcessExecutionException("Unable to persist process instance.", e);
 		}
 
@@ -158,7 +158,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 					+ " includes NO 'ProcessInstanceId'");
 			}
 			
-			ProcessInstance pi = loadProcessInstance(pendingReq.getProcessInstanceId());
+			final ProcessInstance pi = loadProcessInstance(pendingReq.getProcessInstanceId());
 
 			if (pi == null ) {
 				throw new ProcessExecutionException("Process instance '" + pendingReq.getProcessInstanceId() + "' does not exist.");
@@ -179,7 +179,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 			if (!ProcessInstanceState.ENDED.equals(pi.getState()))
 				saveOrUpdateProcessInstance(pi);
 				
-		} catch (EAAFException e) {
+		} catch (final EAAFException e) {
 			throw new ProcessExecutionException("Unable to load/save process instance.", e);
 
 		} finally {
@@ -198,7 +198,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 					+ " includes NO 'ProcessInstanceId'");
 			}
 			
-			ProcessInstance pi = loadProcessInstance(pendingReq.getProcessInstanceId());
+			final ProcessInstance pi = loadProcessInstance(pendingReq.getProcessInstanceId());
 
 			if (pi == null ) {
 				throw new ProcessExecutionException("Process instance '" + pendingReq.getProcessInstanceId() + "' does not exist.");
@@ -223,7 +223,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 			if (!ProcessInstanceState.ENDED.equals(pi.getState()))
 				saveOrUpdateProcessInstance(pi);
 						
-		} catch (EAAFException e) {
+		} catch (final EAAFException e) {
 			throw new ProcessExecutionException("Unable to load/save process instance.", e);
 
 		} finally {
@@ -239,7 +239,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 	 * @throws ProcessExecutionException Thrown in case of error (when the referenced class does not implement {@link Task} for instance).
 	 */
 	private Task createTaskInstance(TaskInfo ti) throws ProcessExecutionException {
-		String clazz = StringUtils.trimToNull(ti.getTaskImplementingClass());
+		final String clazz = StringUtils.trimToNull(ti.getTaskImplementingClass());
 		Task task = null;
 		
 		if (clazz != null) {
@@ -248,7 +248,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 			try {
 				instanceClass = context.getBean(clazz);
 				
-			} catch (Exception e) {
+			} catch (final Exception e) {
 				throw new ProcessExecutionException("Unable to get class '" + clazz + "' associated with task '" + ti.getId() + "' .", e);
 				
 			}
@@ -259,7 +259,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 			try {
 				task = (Task) instanceClass;
 				
-			} catch (Exception e) {
+			} catch (final Exception e) {
 				throw new ProcessExecutionException("Unable to instantiate class '" + clazz + "' associated with task '" + ti.getId() + "' .", e);
 			}
 		}
@@ -277,19 +277,19 @@ public class ProcessEngineImpl implements ProcessEngine {
 		if (ProcessInstanceState.ENDED.equals(pi.getState())) {
 			throw new ProcessExecutionException("Process for instance '" + pi.getId() + "' has already been ended.");
 		}
-		ProcessDefinition pd = pi.getProcessDefinition();
-		ProcessNode processNode = pd.getProcessNode(pi.getNextId());
+		final ProcessDefinition pd = pi.getProcessDefinition();
+		final ProcessNode processNode = pd.getProcessNode(pi.getNextId());
 		log.debug("Processing node '{}'.", processNode.getId());
 		
 		// distinguish process node types StartEvent, TaskInfo and EndEvent
 		
 		if (processNode instanceof TaskInfo) {
 			// TaskInfo types need to be executed
-			TaskInfo ti = (TaskInfo) processNode;
+			final TaskInfo ti = (TaskInfo) processNode;
 			MDC.put(MDC_CTX_TASK_NAME, ti.getId());
 			try {
 				log.debug("Processing task '{}'.", ti.getId());
-				Task task = createTaskInstance(ti);
+				final Task task = createTaskInstance(ti);
 				if (task != null) {
 					try {
 						log.debug("Executing task implementation for task '{}'.", ti.getId());
@@ -297,35 +297,39 @@ public class ProcessEngineImpl implements ProcessEngine {
 						pendingReq = task.execute(pendingReq, pi.getExecutionContext());
 						log.debug("Returned from execution of task '{}'.", ti.getId());
 						log.trace("Execution context after task execution: {}", pi.getExecutionContext().keySet());
-					} catch (Throwable t) {
+												
+					} catch (final Throwable t) {
 						throw new ProcessExecutionException("Error executing task '" + ti.getId() + "'.", t);
+						
+					}
+					
+					//check if process was cancelled dynamically by task
+					if (pi.getExecutionContext().isProcessCancelled()) {
+						log.debug("Processing task '{}' was cancelled by Task: '{}'.", pi.getId(), ti.getId());
+						processFinishEvent(pi);
+						return;
+						
 					}
+					
 				} else {
 					log.debug("No task implementing class set.");
+					
 				}
 			} finally {
 				MDC.remove(MDC_CTX_TASK_NAME);
+				
 			}
 			
 		} else if (processNode instanceof EndEvent) {
-			log.info("Finishing process instance '{}'.", pi.getId());
-
-			try {
-				piStoreDao.remove(pi.getId());
-				
-			} catch (EAAFException e) {
-				throw new ProcessExecutionException("Unable to remove process instance.", e);
-				
-			}
-			pi.setState(ProcessInstanceState.ENDED);
-			log.debug("Final process context: {}", pi.getExecutionContext().keySet());
+			processFinishEvent(pi);
 			return;
+			
 		}
 		
 		final ExpressionEvaluationContext expressionContext = new ExpressionEvaluationContextImpl(pi);
 		
 		// traverse pointer
-		Transition t = IterableUtils.find(processNode.getOutgoingTransitions(), new Predicate<Transition>() {
+		final Transition t = IterableUtils.find(processNode.getOutgoingTransitions(), new Predicate<Transition>() {
 			@Override
 			public boolean evaluate(Transition transition) {
 				if (transitionConditionExpressionEvaluator != null && transition.getConditionExpression() != null) {
@@ -356,7 +360,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 			execute(pi, pendingReq);
 		}
 	}
-
+	
 	@Override
 	public ProcessInstance getProcessInstance(String processInstanceId) {
 
@@ -364,7 +368,7 @@ public class ProcessEngineImpl implements ProcessEngine {
 		try {
 			processInstance = loadProcessInstance(processInstanceId);
 
-		} catch (EAAFException e) {
+		} catch (final EAAFException e) {
 			throw new RuntimeException("The process instance '" + processInstanceId + "' could not be retrieved.", e);
 		}
 
@@ -381,12 +385,12 @@ public class ProcessEngineImpl implements ProcessEngine {
 	 * @throws MOADatabaseException Thrown if an error occurs while accessing the database.
 	 */
 	private void saveOrUpdateProcessInstance(ProcessInstance processInstance) throws EAAFException {
-		ProcessInstanceStore store = new ProcessInstanceStore();
+		final ProcessInstanceStore store = new ProcessInstanceStore();
 
-		ExecutionContext ctx = processInstance.getExecutionContext();
+		final ExecutionContext ctx = processInstance.getExecutionContext();
 
-		Map<String, Serializable> ctxData = new HashMap<String, Serializable>();
-		for (String key : ctx.keySet()) {
+		final Map<String, Serializable> ctxData = new HashMap<String, Serializable>();
+		for (final String key : ctx.keySet()) {
 			ctxData.put(key, ctx.get(key));
 		}
 		store.setExecutionContextData(ctxData);
@@ -408,20 +412,20 @@ public class ProcessEngineImpl implements ProcessEngine {
 	 */
 	private ProcessInstance loadProcessInstance(String processInstanceId) throws EAAFException {
 
-		ProcessInstanceStore piStore = piStoreDao.load(processInstanceId);
+		final ProcessInstanceStore piStore = piStoreDao.load(processInstanceId);
 
 		if (piStore == null) {
 			return null;
 		}
 
-		ExecutionContext executionContext = new ExecutionContextImpl(piStore.getProcessInstanceId());
+		final ExecutionContext executionContext = new ExecutionContextImpl(piStore.getProcessInstanceId());
 
-		Map<String, Serializable> executionContextData = piStore.getExecutionContextData();
-		for (String key : executionContextData.keySet()) {
+		final Map<String, Serializable> executionContextData = piStore.getExecutionContextData();
+		for (final String key : executionContextData.keySet()) {
 			executionContext.put(key, executionContextData.get(key));
 		}
 
-		ProcessInstance pi = new ProcessInstance(processDefinitions.get(piStore.getProcessDefinitionId()), executionContext);
+		final ProcessInstance pi = new ProcessInstance(processDefinitions.get(piStore.getProcessDefinitionId()), executionContext);
 		pi.setNextId(piStore.getNextTaskId());
 		pi.setState(piStore.getProcessState());
 
@@ -441,10 +445,31 @@ public class ProcessEngineImpl implements ProcessEngine {
 		try {
 			piStoreDao.remove(processInstanceId);
 			
-		} catch (EAAFException e) {
+		} catch (final EAAFException e) {
+			throw new ProcessExecutionException("Unable to remove process instance.", e);
+			
+		}
+		
+	}
+	
+	/**
+	 * Finish a process-flow and remove any process-flow related information
+	 * 
+	 * @param pi
+	 * @throws ProcessExecutionException
+	 */
+	private void processFinishEvent(ProcessInstance pi) throws ProcessExecutionException {
+		log.info("Finishing process instance '{}'.", pi.getId());
+
+		try {
+			piStoreDao.remove(pi.getId());
+			
+		} catch (final EAAFException e) {
 			throw new ProcessExecutionException("Unable to remove process instance.", e);
 			
 		}
+		pi.setState(ProcessInstanceState.ENDED);
+		log.debug("Final process context: {}", pi.getExecutionContext().keySet());
 		
 	}
 	
@@ -458,11 +483,11 @@ public class ProcessEngineImpl implements ProcessEngine {
 	 */
 	private void postValidationOfProcessDefintion(ProcessDefinition pd) throws ProcessDefinitionParserException{
 		try {
-			for(TaskInfo task : pd.getTaskInfos().values()) {
+			for(final TaskInfo task : pd.getTaskInfos().values()) {
 				createTaskInstance(task);		
 			}
 			
-		} catch (ProcessExecutionException e) {
+		} catch (final ProcessExecutionException e) {
 			log.error("Post-validation of process definition: {} find an error: {}", pd.getId(), e.getMessage());
 			throw new ProcessDefinitionParserException("Post-validation find an error in process definition:" + pd.getId(), e);
 			
diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessInstance.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessInstance.java
index 17d8ea8f..6db1dc7d 100644
--- a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessInstance.java
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/ProcessInstance.java
@@ -49,13 +49,13 @@ public class ProcessInstance implements Serializable {
 	private static final long serialVersionUID = 1L;
 	private static final int RND_ID_LENGTH = 22;
 
-	private ProcessDefinition processDefinition;
+	private final ProcessDefinition processDefinition;
 	private String nextId;
 	private Date lru;
-	private ExecutionContext executionContext;
+	private final ExecutionContext executionContext;
 	private ProcessInstanceState state = ProcessInstanceState.NOT_STARTED;
 
-	private Logger log = LoggerFactory.getLogger(getClass());
+	private final Logger log = LoggerFactory.getLogger(getClass());
 
 	/**
 	 * Creates a new process instance, based on a given process definition and a
@@ -74,7 +74,7 @@ public class ProcessInstance implements Serializable {
 			executionContext = new ExecutionContextImpl();
 		}
 		if (executionContext.getProcessInstanceId() == null) {
-			String pdIdLocalPart = RandomStringUtils.random(RND_ID_LENGTH, 0, 0, true, true, null,
+			final String pdIdLocalPart = RandomStringUtils.random(RND_ID_LENGTH, 0, 0, true, true, null,
 					SecureRandomHolder.getInstance());
 			executionContext.setProcessInstanceId(this.processDefinition.getId() + "-" + pdIdLocalPart);
 		} else {
@@ -169,7 +169,7 @@ public class ProcessInstance implements Serializable {
 
 	@Override
 	public String toString() {
-		StringBuilder builder = new StringBuilder();
+		final StringBuilder builder = new StringBuilder();
 		builder.append("ProcessInstance [");
 		builder.append("id=").append(executionContext.getProcessInstanceId());
 		builder.append(", idle since=").append(
diff --git a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HalloWeltTask.java b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HalloWeltTask.java
index 40399e58..743a61da 100644
--- a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HalloWeltTask.java
+++ b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HalloWeltTask.java
@@ -44,7 +44,7 @@ public class HalloWeltTask implements Task {
 	@Override
 	public IRequest execute(IRequest pendingReq, ExecutionContext executionContext) {
 		System.out.println("Hallo Welt");
-		return null;
+		return pendingReq;
 	}
 
 }
diff --git a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HelloWorldTask.java b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HelloWorldTask.java
index a2d8b3fb..c6da16b4 100644
--- a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HelloWorldTask.java
+++ b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/HelloWorldTask.java
@@ -44,7 +44,7 @@ public class HelloWorldTask implements Task {
 	@Override
 	public IRequest execute(IRequest pendingReq, ExecutionContext executionContext) {
 		System.out.println("Hello World");
-		return null;
+		return pendingReq;
 	}
 
 }
diff --git a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ProcessEngineTest.java b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ProcessEngineTest.java
index 78fdde61..dc45534e 100644
--- a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ProcessEngineTest.java
+++ b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ProcessEngineTest.java
@@ -33,6 +33,7 @@ import static org.junit.Assert.assertEquals;
 import java.io.IOException;
 import java.io.InputStream;
 
+import org.apache.commons.lang3.RandomStringUtils;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -44,6 +45,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
 import at.gv.egiz.eaaf.core.api.idp.process.ProcessEngine;
 import at.gv.egiz.eaaf.core.exceptions.ProcessExecutionException;
+import at.gv.egiz.eaaf.core.exceptions.TaskExecutionException;
 import at.gv.egiz.eaaf.core.impl.idp.module.test.TestRequestImpl;
 import at.gv.egiz.eaaf.core.impl.idp.process.ProcessDefinitionParser;
 import at.gv.egiz.eaaf.core.impl.idp.process.ProcessDefinitionParserException;
@@ -64,7 +66,7 @@ public class ProcessEngineTest {
 	public void init() throws IOException, ProcessDefinitionParserException {
 		
 		if (!isInitialized) {
-			ProcessDefinitionParser pdp = new ProcessDefinitionParser();
+			final ProcessDefinitionParser pdp = new ProcessDefinitionParser();
 
 			if (pe == null) {
 				pe = applicationContext.getBean("processEngine", ProcessEngine.class);
@@ -79,29 +81,19 @@ public class ProcessEngineTest {
 				((ProcessEngineImpl) pe).registerProcessDefinition(pdp.parse(in));
 			}
 
+			try (InputStream in = ProcessEngineTest.class.getResourceAsStream("/process/test/SampleProcessDefinition4.xml")) {
+				((ProcessEngineImpl) pe).registerProcessDefinition(pdp.parse(in));
+			}
+			
+			try (InputStream in = ProcessEngineTest.class.getResourceAsStream("/process/test/SampleProcessDefinition5.xml")) {
+				((ProcessEngineImpl) pe).registerProcessDefinition(pdp.parse(in));
+			}
+			
 			//initHibernateForTesting();
 			isInitialized = true;
 		}
 	}
 	
-	private static void initHibernateForTesting() throws IOException{
-
-//		InputStream in = ProcessEngineTest.class.getResourceAsStream("/at/gv/egovernment/moa/id/process/hibernate.configuration.test.properties");
-//		Properties props = new Properties();
-//		props.load(in);
-//
-//		try {
-//			//ConfigurationDBUtils.initHibernate(props);
-//			Configuration config = new Configuration();
-//			config.addProperties(props);
-//			//config.addAnnotatedClass(ProcessInstanceStore.class);
-//			config.addAnnotatedClass(AssertionStore.class);
-//			//MOASessionDBUtils.initHibernate(config, props);
-//		} catch (Exception e) {
-//			e.printStackTrace();
-//		}
-	}
-	
 	@Test
 	public void wrongProcessDefinition() throws IOException {
 		try (InputStream in = ProcessEngineTest.class.getResourceAsStream("/process/test/SampleProcessDefinition3.xml")) {
@@ -109,7 +101,7 @@ public class ProcessEngineTest {
 				((ProcessEngineImpl) pe).registerProcessDefinition(in);
 				Assert.fail();
 				
-			} catch (ProcessDefinitionParserException e) {
+			} catch (final ProcessDefinitionParserException e) {
 				Assert.assertTrue(e.getMessage().contains("Post-validation find an error in process definition"));
 			}
 		}
@@ -119,9 +111,9 @@ public class ProcessEngineTest {
 	@Test
 	public void testSampleProcess1() throws IOException, ProcessDefinitionParserException, ProcessExecutionException {
 		
-		TestRequestImpl testReq = new TestRequestImpl();
+		final TestRequestImpl testReq = new TestRequestImpl();
 		
-		String piId = pe.createProcessInstance("SampleProcess1");
+		final String piId = pe.createProcessInstance("SampleProcess1");
 		ProcessInstance pi = pe.getProcessInstance(piId);
 		assertEquals(NOT_STARTED, pi.getState());
 
@@ -139,7 +131,7 @@ public class ProcessEngineTest {
 			throw new ProcessExecutionException("ProcessInstance should be removed already, but it was found.");
 			//assertEquals(ENDED, pi.getState());
 			
-		} catch (IllegalArgumentException e) {
+		} catch (final IllegalArgumentException e) {
 			// do nothing because processInstance should be already removed 
 			
 		}
@@ -148,9 +140,9 @@ public class ProcessEngineTest {
 	@Test
 	public void testSampleProcess2() throws IOException, ProcessDefinitionParserException, ProcessExecutionException {
 
-		TestRequestImpl testReq = new TestRequestImpl();
+		final TestRequestImpl testReq = new TestRequestImpl();
 		
-		String piId = pe.createProcessInstance("SampleProcess2");
+		final String piId = pe.createProcessInstance("SampleProcess2");
 		ProcessInstance pi = pe.getProcessInstance(piId);
 		assertEquals(NOT_STARTED, pi.getState());
 
@@ -168,14 +160,64 @@ public class ProcessEngineTest {
 			throw new ProcessExecutionException("ProcessInstance should be removed already, but it was found.");
 			//assertEquals(ENDED, pi.getState());
 			
-		} catch (IllegalArgumentException e) {
+		} catch (final IllegalArgumentException e) {
 			// do nothing because processInstance should be already removed 
 			
 		}
+				
+	}
+
+	@Test
+	public void testSampleProcess4() throws IOException, ProcessDefinitionParserException, ProcessExecutionException {
+
+		final TestRequestImpl testReq = new TestRequestImpl();
+		testReq.setPendingReqId(RandomStringUtils.randomAlphanumeric(5));
 		
-		
+		final String piId = pe.createProcessInstance("SampleProcess4");
+		final ProcessInstance pi = pe.getProcessInstance(piId);
+		assertEquals(NOT_STARTED, pi.getState());
+
+		// start process
+		testReq.setProcessInstanceID(piId);
+		try {
+			pe.start(testReq);
+			Assert.fail("Task exception not handled");
+			
+		} catch (final ProcessExecutionException e1) {			
+			org.springframework.util.Assert.isInstanceOf(TaskExecutionException.class, e1.getCause(), "No TaskExecutionException");
+			Assert.assertEquals("Wrong error-msg", "jUnit Test", e1.getCause().getMessage());
+			Assert.assertEquals("Wrong pendingReqId", testReq.getPendingRequestId(), ((TaskExecutionException) e1.getCause()).getPendingRequestID());
+			org.springframework.util.Assert.isInstanceOf(RuntimeException.class, e1.getCause().getCause(), "Wrong Exception in TaskExecutionException");
+		}
+	
+				
 	}
+	
+	@Test
+	public void testSampleProcess5() throws IOException, ProcessDefinitionParserException, ProcessExecutionException {
 
+		final TestRequestImpl testReq = new TestRequestImpl();
+		
+		final String piId = pe.createProcessInstance("SampleProcess5");
+		ProcessInstance pi = pe.getProcessInstance(piId);
+		assertEquals(NOT_STARTED, pi.getState());
+
+		// start process
+		testReq.setProcessInstanceID(piId);
+		pe.start(testReq);
+
+		try {
+			pi = pe.getProcessInstance(piId);
+			
+		} catch (final IllegalArgumentException e) {
+			Assert.assertTrue("wrong error-msg", e.getMessage().contains("does not/no longer exist."));
+			Assert.assertTrue("wrong process-instance-id", e.getMessage().contains(piId));
+			
+		}
+		
+		
+	}
+	
 	@Test(expected = IllegalArgumentException.class)
 	public void testProcessInstanceDoesNotExist() {
 		pe.getProcessInstance("does not exist");
diff --git a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/StopProcessFlagTask.java b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/StopProcessFlagTask.java
new file mode 100644
index 00000000..8cd76eaa
--- /dev/null
+++ b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/StopProcessFlagTask.java
@@ -0,0 +1,52 @@
+/*******************************************************************************
+ * Copyright 2017 Graz University of Technology
+ * EAAF-Core Components has been developed in a cooperation between EGIZ,  
+ * A-SIT Plus, A-SIT, and Graz University of Technology.
+ *
+ * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
+ * the European Commission - subsequent versions of the EUPL (the "Licence");
+ * You may not use this work except in compliance with the Licence.
+ * You may obtain a copy of the Licence at:
+ * https://joinup.ec.europa.eu/news/understanding-eupl-v12
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the Licence is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing permissions and
+ * limitations under the Licence.
+ *  
+ * This product combines work with different licenses. See the "NOTICE" text
+ * file for details on the various modules and licenses.
+ * The "NOTICE" text file is part of the distribution. Any derivative works
+ * that you distribute must include a readable copy of the "NOTICE" text file.
+ *******************************************************************************/
+/*******************************************************************************
+ *******************************************************************************/
+/*******************************************************************************
+ *******************************************************************************/
+package at.gv.egiz.eaaf.core.impl.idp.process.test;
+
+import org.springframework.stereotype.Service;
+
+import at.gv.egiz.eaaf.core.api.IRequest;
+import at.gv.egiz.eaaf.core.api.idp.process.ExecutionContext;
+import at.gv.egiz.eaaf.core.api.idp.process.Task;
+
+/**
+ * Simple task that just outputs a "Hello World" text to the console.
+ * 
+ * @author tknall
+ * 
+ */
+@Service("HelloWorldTask")
+public class StopProcessFlagTask implements Task {
+ 
+	@Override
+	public IRequest execute(IRequest pendingReq, ExecutionContext executionContext) {
+		System.out.println("Stop process-flow dynamically from task");
+		executionContext.setCanceleProcessFlag();
+		
+		return pendingReq;
+	}
+
+}
diff --git a/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ThrowExceptionTask.java b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ThrowExceptionTask.java
new file mode 100644
index 00000000..ecd139c8
--- /dev/null
+++ b/eaaf_core/src/test/java/at/gv/egiz/eaaf/core/impl/idp/process/test/ThrowExceptionTask.java
@@ -0,0 +1,52 @@
+/*******************************************************************************
+ * Copyright 2017 Graz University of Technology
+ * EAAF-Core Components has been developed in a cooperation between EGIZ,  
+ * A-SIT Plus, A-SIT, and Graz University of Technology.
+ *
+ * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
+ * the European Commission - subsequent versions of the EUPL (the "Licence");
+ * You may not use this work except in compliance with the Licence.
+ * You may obtain a copy of the Licence at:
+ * https://joinup.ec.europa.eu/news/understanding-eupl-v12
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the Licence is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing permissions and
+ * limitations under the Licence.
+ *  
+ * This product combines work with different licenses. See the "NOTICE" text
+ * file for details on the various modules and licenses.
+ * The "NOTICE" text file is part of the distribution. Any derivative works
+ * that you distribute must include a readable copy of the "NOTICE" text file.
+ *******************************************************************************/
+/*******************************************************************************
+ *******************************************************************************/
+/*******************************************************************************
+ *******************************************************************************/
+package at.gv.egiz.eaaf.core.impl.idp.process.test;
+
+import org.springframework.stereotype.Service;
+
+import at.gv.egiz.eaaf.core.api.IRequest;
+import at.gv.egiz.eaaf.core.api.idp.process.ExecutionContext;
+import at.gv.egiz.eaaf.core.api.idp.process.Task;
+import at.gv.egiz.eaaf.core.exceptions.TaskExecutionException;
+
+/**
+ * Simple task that just outputs a "Hello World" text to the console.
+ * 
+ * @author tknall
+ * 
+ */
+@Service("HelloWorldTask")
+public class ThrowExceptionTask implements Task {
+ 
+	@Override
+	public IRequest execute(IRequest pendingReq, ExecutionContext executionContext) throws TaskExecutionException {
+		System.out.println("Stop process-flow dynamically from task");
+		throw new TaskExecutionException(pendingReq, "jUnit Test", new RuntimeException("jUnit test exception handling"));
+		
+	}
+
+}
diff --git a/eaaf_core/src/test/resources/process/spring/test/SpringExpressionAwareProcessEngineTest-context.xml b/eaaf_core/src/test/resources/process/spring/test/SpringExpressionAwareProcessEngineTest-context.xml
index ad94c6d4..ebbd89e9 100644
--- a/eaaf_core/src/test/resources/process/spring/test/SpringExpressionAwareProcessEngineTest-context.xml
+++ b/eaaf_core/src/test/resources/process/spring/test/SpringExpressionAwareProcessEngineTest-context.xml
@@ -30,6 +30,12 @@
 	<bean id="HalloWeltTask" 
 				class="at.gv.egiz.eaaf.core.impl.idp.process.test.HalloWeltTask"/>
 				
+	<bean id="StopProcessFlagTask" 
+				class="at.gv.egiz.eaaf.core.impl.idp.process.test.StopProcessFlagTask"/>
+	
+	<bean id="ThrowExceptionTask" 
+				class="at.gv.egiz.eaaf.core.impl.idp.process.test.ThrowExceptionTask"/>
+				
 	<bean id="SelectBKUTask" 
 				class="at.gv.egiz.eaaf.core.impl.idp.process.spring.test.task.SelectBKUTask"/>
 				
diff --git a/eaaf_core/src/test/resources/process/test/SampleProcessDefinition4.xml b/eaaf_core/src/test/resources/process/test/SampleProcessDefinition4.xml
new file mode 100644
index 00000000..c88afd05
--- /dev/null
+++ b/eaaf_core/src/test/resources/process/test/SampleProcessDefinition4.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ -->
+
+<tns:ProcessDefinition
+	id="SampleProcess4"
+	xmlns:tns="http://reference.e-government.gv.at/namespace/moa/process/definition/v1"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://reference.e-government.gv.at/namespace/moa/process/definition/v1 ../../main/resources/process/ProcessDefinition.xsd ">
+
+	<tns:StartEvent id="start" />
+
+	<tns:Task id="task1" class="HelloWorldTask" />
+	<tns:Task id="task2" class="ThrowExceptionTask" />
+	<tns:Task id="task3" />
+
+	<tns:EndEvent id="end" />
+
+	<tns:Transition id="fromStart" from="start" to="task1" conditionExpression="true" />
+	<tns:Transition from="task1" to="task2" />
+	<tns:Transition from="task2" to="task3" />
+	<tns:Transition from="task3" to="end" />
+	
+</tns:ProcessDefinition>
diff --git a/eaaf_core/src/test/resources/process/test/SampleProcessDefinition5.xml b/eaaf_core/src/test/resources/process/test/SampleProcessDefinition5.xml
new file mode 100644
index 00000000..e0072e62
--- /dev/null
+++ b/eaaf_core/src/test/resources/process/test/SampleProcessDefinition5.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ -->
+
+<tns:ProcessDefinition
+	id="SampleProcess5"
+	xmlns:tns="http://reference.e-government.gv.at/namespace/moa/process/definition/v1"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://reference.e-government.gv.at/namespace/moa/process/definition/v1 ../../main/resources/process/ProcessDefinition.xsd ">
+
+	<tns:StartEvent id="start" />
+
+	<tns:Task id="task1" class="HelloWorldTask" />
+	<tns:Task id="task2" class="StopProcessFlagTask" />
+	<tns:Task id="task3" class="ThrowExceptionTask" />
+
+	<tns:EndEvent id="end" />
+
+	<tns:Transition id="fromStart" from="start" to="task1" conditionExpression="true" />
+	<tns:Transition from="task1" to="task2" />
+	<tns:Transition from="task2" to="task3" />
+	<tns:Transition from="task3" to="end" />
+	
+</tns:ProcessDefinition>
diff --git a/eaaf_core_api/src/main/java/at/gv/egiz/eaaf/core/api/idp/process/ExecutionContext.java b/eaaf_core_api/src/main/java/at/gv/egiz/eaaf/core/api/idp/process/ExecutionContext.java
index 38a66d4c..319db027 100644
--- a/eaaf_core_api/src/main/java/at/gv/egiz/eaaf/core/api/idp/process/ExecutionContext.java
+++ b/eaaf_core_api/src/main/java/at/gv/egiz/eaaf/core/api/idp/process/ExecutionContext.java
@@ -38,6 +38,21 @@ import java.util.Set;
 public interface ExecutionContext extends Serializable {
 
 	/**
+	 * Flag that indicates that a Task canceled the current {@link ExecutionContext}
+	 * 
+	 * @return true if the process-flow was marked as canceled, otherwise false
+	 */
+	boolean isProcessCancelled(); 
+	
+	/**
+	 * Mark this {@link ExecutionContext} as cancelled
+	 * 
+	 * The process-flow engine will stop execution when the task that sets this flag is finished
+	 * 
+	 */
+	void setCanceleProcessFlag();
+	
+	/**
 	 * Returns the identifier of underlying process instance.
 	 * 
 	 * @return The identifier of the process instance.