reworked autostart process with unique instances based on BPMN signals

The new ping autostart process implementation uses an event based
gateway to either wait for a timer to fire after 24 hours or a global
signal to abort.
The abort signal is send as the first step of the autostart process to
stop existing instances and based on a stopPingAutostart Task resource.
The new implementation does not require (nor allow) to specify a
business-key via Task resource.
If a stopPingAutostart Task resource is send while the autostart process
is active and not waiting, nothing happens. Stopping the autostart
process is only possible while the process is sleeping but then is
stopped immediately.

Author: hhund

dsf-bpe-process-ping/src/main/java/org/highmed/dsf/bpe/service/StartTimer.java renamed to dsf-bpe-process-ping/src/main/java/org/highmed/dsf/bpe/service/SetTargetAndConfigureTimer.java

@@ -1,12 +1,14 @@
 package org.highmed.dsf.bpe.service;
 
 import static org.highmed.dsf.bpe.ConstantsBase.BPMN_EXECUTION_VARIABLE_TARGET;
-import static org.highmed.dsf.bpe.ConstantsPing.BPMN_EXECUTION_VARIABLE_STOP_TIMER;
 import static org.highmed.dsf.bpe.ConstantsPing.BPMN_EXECUTION_VARIABLE_TIMER_INTERVAL;
 import static org.highmed.dsf.bpe.ConstantsPing.CODESYSTEM_HIGHMED_PING;
 import static org.highmed.dsf.bpe.ConstantsPing.CODESYSTEM_HIGHMED_PING_VALUE_TIMER_INTERVAL;
 import static org.highmed.dsf.bpe.ConstantsPing.TIMER_INTERVAL_DEFAULT_VALUE;
 
+import java.util.Objects;
+
+import org.camunda.bpm.engine.delegate.BpmnError;
 import org.camunda.bpm.engine.delegate.DelegateExecution;
 import org.camunda.bpm.engine.variable.Variables;
 import org.highmed.dsf.bpe.delegate.AbstractServiceDelegate;
@@ -20,14 +22,14 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class StartTimer extends AbstractServiceDelegate
+public class SetTargetAndConfigureTimer extends AbstractServiceDelegate
 {
-	private static final Logger logger = LoggerFactory.getLogger(StartTimer.class);
+	private static final Logger logger = LoggerFactory.getLogger(SetTargetAndConfigureTimer.class);
 
 	private final OrganizationProvider organizationProvider;
 	private final EndpointProvider endpointProvider;
 
-	public StartTimer(FhirWebserviceClientProvider clientProvider, TaskHelper taskHelper,
+	public SetTargetAndConfigureTimer(FhirWebserviceClientProvider clientProvider, TaskHelper taskHelper,
 			ReadAccessHelper readAccessHelper, OrganizationProvider organizationProvider,
 			EndpointProvider endpointProvider)
 	{
@@ -38,11 +40,17 @@ public StartTimer(FhirWebserviceClientProvider clientProvider, TaskHelper taskHe
 	}
 
 	@Override
-	protected void doExecute(DelegateExecution execution) throws Exception
+	public void afterPropertiesSet() throws Exception
 	{
-		logger.debug("Setting variable '{}' to false", BPMN_EXECUTION_VARIABLE_STOP_TIMER);
-		execution.setVariable(BPMN_EXECUTION_VARIABLE_STOP_TIMER, Variables.booleanValue(false));
+		super.afterPropertiesSet();
+
+		Objects.requireNonNull(organizationProvider, "organizationProvider");
+		Objects.requireNonNull(endpointProvider, "endpointProvider");
+	}
 
+	@Override
+	protected void doExecute(DelegateExecution execution) throws BpmnError, Exception
+	{
 		String timerInterval = getTimerInterval(execution);
 		logger.debug("Setting variable '{}' to {}", BPMN_EXECUTION_VARIABLE_TIMER_INTERVAL, timerInterval);
 		execution.setVariable(BPMN_EXECUTION_VARIABLE_TIMER_INTERVAL, Variables.stringValue(timerInterval));

dsf-bpe-process-ping/src/main/java/org/highmed/dsf/bpe/service/StopTimer.java

@@ -9,8 +9,7 @@
 import org.highmed.dsf.bpe.service.LogPong;
 import org.highmed.dsf.bpe.service.SelectPingTargets;
 import org.highmed.dsf.bpe.service.SelectPongTarget;
-import org.highmed.dsf.bpe.service.StartTimer;
-import org.highmed.dsf.bpe.service.StopTimer;
+import org.highmed.dsf.bpe.service.SetTargetAndConfigureTimer;
 import org.highmed.dsf.bpe.util.PingStatusGenerator;
 import org.highmed.dsf.fhir.authorization.read.ReadAccessHelper;
 import org.highmed.dsf.fhir.client.FhirWebserviceClientProvider;
@@ -45,9 +44,10 @@ public class PingConfig
 	private FhirContext fhirContext;
 
 	@Bean
-	public StartTimer startTimer()
+	public SetTargetAndConfigureTimer setTargetAndConfigureTimer()
 	{
-		return new StartTimer(clientProvider, taskHelper, readAccessHelper, organizationProvider, endpointProvider);
+		return new SetTargetAndConfigureTimer(clientProvider, taskHelper, readAccessHelper, organizationProvider,
+				endpointProvider);
 	}
 
 	@Bean
@@ -56,12 +56,6 @@ public SendStartPing sendStartPing()
 		return new SendStartPing(clientProvider, taskHelper, readAccessHelper, organizationProvider, fhirContext);
 	}
 
-	@Bean
-	public StopTimer stopTimer()
-	{
-		return new StopTimer(clientProvider, taskHelper, readAccessHelper);
-	}
-
 	@Bean
 	public PingStatusGenerator responseGenerator()
 	{