[New][Backport] Implemented async parallel loading from pageable persistence layers

li.strolch.agent/src/main/java/li/strolch/agent/impl/CachedRealm.java

@@ -15,20 +15,15 @@
  */
 package li.strolch.agent.impl;
 
-import java.text.MessageFormat;
-import java.util.List;
-import java.util.Set;
-
-import li.strolch.agent.api.*;
-import li.strolch.model.Order;
-import li.strolch.model.Resource;
-import li.strolch.model.activity.Activity;
-import li.strolch.persistence.api.*;
+import li.strolch.agent.api.AuditTrail;
+import li.strolch.agent.api.ComponentContainer;
+import li.strolch.agent.api.StrolchAgent;
+import li.strolch.persistence.api.PersistenceHandler;
+import li.strolch.persistence.api.StrolchTransaction;
 import li.strolch.privilege.model.Certificate;
 import li.strolch.privilege.model.PrivilegeContext;
 import li.strolch.runtime.configuration.ComponentConfiguration;
 import li.strolch.utils.dbc.DBC;
-import li.strolch.utils.helper.StringHelper;
 
 /**
  * @author Robert von Burg <eitch@eitchnet.ch>
@@ -63,17 +58,17 @@ public class CachedRealm extends InternalStrolchRealm {
 	}
 
 	@Override
-	public ResourceMap getResourceMap() {
+	public CachedResourceMap getResourceMap() {
 		return this.resourceMap;
 	}
 
 	@Override
-	public OrderMap getOrderMap() {
+	public CachedOrderMap getOrderMap() {
 		return this.orderMap;
 	}
 
 	@Override
-	public ActivityMap getActivityMap() {
+	public CachedActivityMap getActivityMap() {
 		return this.activityMap;
 	}
 
@@ -82,6 +77,10 @@ public class CachedRealm extends InternalStrolchRealm {
 		return this.auditTrail;
 	}
 
+	StrolchAgent getAgent() {
+		return this.container.getAgent();
+	}
+
 	@Override
 	public void initialize(ComponentContainer container, ComponentConfiguration configuration) {
 		super.initialize(container, configuration);
@@ -100,69 +99,7 @@ public class CachedRealm extends InternalStrolchRealm {
 	@Override
 	public void start(PrivilegeContext privilegeContext) {
 		super.start(privilegeContext);
-
-		long start = System.nanoTime();
-		int nrOfOrders = 0;
-		int nrOfResources = 0;
-		int nrOfActivities = 0;
-
-		logger.info(MessageFormat.format("Loading Model from Database for realm {0}...", getRealm())); //$NON-NLS-1$
-
-		try (StrolchTransaction tx = openTx(privilegeContext.getCertificate(), "strolch_boot", false)) {
-			ResourceDao resourceDao = tx.getPersistenceHandler().getResourceDao(tx);
-			logger.info("Reading " + resourceDao.querySize() + " Resources from DB...");
-			Set<String> resourceTypes = resourceDao.queryTypes();
-			for (String type : resourceTypes) {
-				logger.info("Reading " + resourceDao.querySize(type) + " Resources of type " + type + " from DB...");
-				List<Resource> resources = resourceDao.queryAll(type);
-				for (Resource resource : resources) {
-					this.resourceMap.insert(resource);
-					nrOfResources++;
-				}
-			}
-
-			tx.commitOnClose();
-		}
-
-		try (StrolchTransaction tx = openTx(privilegeContext.getCertificate(), "strolch_boot", false)) {
-			OrderDao orderDao = tx.getPersistenceHandler().getOrderDao(tx);
-			logger.info("Reading " + orderDao.querySize() + " Orders from DB...");
-			Set<String> orderTypes = orderDao.queryTypes();
-			for (String type : orderTypes) {
-				logger.info("Reading " + orderDao.querySize(type) + " Orders of type " + type + " from DB...");
-				List<Order> orders = orderDao.queryAll(type);
-				for (Order order : orders) {
-					this.orderMap.insert(order);
-					nrOfOrders++;
-				}
-			}
-
-			tx.commitOnClose();
-		}
-
-		try (StrolchTransaction tx = openTx(privilegeContext.getCertificate(), "strolch_boot", false)) {
-			ActivityDao activityDao = tx.getPersistenceHandler().getActivityDao(tx);
-			logger.info("Reading " + activityDao.querySize() + " Activities from DB...");
-			Set<String> activityTypes = activityDao.queryTypes();
-			for (String type : activityTypes) {
-				logger.info("Reading " + activityDao.querySize(type) + " Activities of type " + type + " from DB...");
-				List<Activity> activities = activityDao.queryAll(type);
-				for (Activity activity : activities) {
-					this.activityMap.insert(activity);
-					nrOfActivities++;
-				}
-			}
-
-			tx.commitOnClose();
-		}
-
-		long duration = System.nanoTime() - start;
-		String durationS = StringHelper.formatNanoDuration(duration);
-		logger.info(MessageFormat
-				.format("Loading Model from Database for realm {0} took {1}.", getRealm(), durationS)); //$NON-NLS-1$
-		logger.info(MessageFormat.format("Loaded {0} Orders", nrOfOrders)); //$NON-NLS-1$
-		logger.info(MessageFormat.format("Loaded {0} Resources", nrOfResources)); //$NON-NLS-1$
-		logger.info(MessageFormat.format("Loaded {0} Activities", nrOfActivities)); //$NON-NLS-1$
+		new CachedRealmLoader(this, this.persistenceHandler, privilegeContext).load(getRealm());
 	}
 
 	@Override

li.strolch.agent/src/main/java/li/strolch/agent/impl/CachedRealmLoader.java

@@ -0,0 +1,178 @@
+package li.strolch.agent.impl;
+
+import static java.lang.Integer.MAX_VALUE;
+import static java.util.concurrent.CompletableFuture.allOf;
+import static java.util.concurrent.CompletableFuture.supplyAsync;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+import java.text.MessageFormat;
+import java.util.*;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import li.strolch.model.StrolchRootElement;
+import li.strolch.persistence.api.PersistenceHandler;
+import li.strolch.persistence.api.StrolchDao;
+import li.strolch.persistence.api.StrolchTransaction;
+import li.strolch.privilege.model.Certificate;
+import li.strolch.privilege.model.PrivilegeContext;
+import li.strolch.utils.dbc.DBC;
+import li.strolch.utils.helper.StringHelper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CachedRealmLoader {
+
+	private static final Logger logger = LoggerFactory.getLogger(CachedRealmLoader.class);
+	public static final int MIN_PAGE_SIZE = 200;
+
+	private final CachedRealm realm;
+	private final PersistenceHandler persistenceHandler;
+	private final PrivilegeContext privilegeContext;
+
+	private final AtomicLong nrOfOrders;
+	private final AtomicLong nrOfResources;
+	private final AtomicLong nrOfActivities;
+
+	public CachedRealmLoader(CachedRealm realm, PersistenceHandler persistenceHandler,
+			PrivilegeContext privilegeContext) {
+		this.realm = realm;
+		this.persistenceHandler = persistenceHandler;
+		this.privilegeContext = privilegeContext;
+		this.nrOfOrders = new AtomicLong();
+		this.nrOfResources = new AtomicLong();
+		this.nrOfActivities = new AtomicLong();
+	}
+
+	public void load(String realm) {
+		long start = System.nanoTime();
+		logger.info(MessageFormat.format("Loading Model from Database for realm {0}...", realm));
+
+		if (this.persistenceHandler.supportsPaging()) {
+			loadElementsPagingAsync("Resources", this.persistenceHandler::getResourceDao, this.realm::getResourceMap,
+					this.nrOfResources);
+			loadElementsPagingAsync("Orders", this.persistenceHandler::getOrderDao, this.realm::getOrderMap,
+					this.nrOfOrders);
+			loadElementsPagingAsync("Activities", this.persistenceHandler::getActivityDao, this.realm::getActivityMap,
+					this.nrOfActivities);
+		} else {
+			loadElements("Resources", this.persistenceHandler::getResourceDao, this.realm::getResourceMap,
+					this.nrOfResources);
+			loadElements("Orders", this.persistenceHandler::getOrderDao, this.realm::getOrderMap, this.nrOfOrders);
+			loadElements("Activities", this.persistenceHandler::getActivityDao, this.realm::getActivityMap,
+					this.nrOfActivities);
+		}
+
+		long duration = System.nanoTime() - start;
+		String durationS = StringHelper.formatNanoDuration(duration);
+		logger.info(MessageFormat.format("Loading Model from Database for realm {0} took {1}.", realm, durationS));
+		logger.info(MessageFormat.format("Loaded {0} Orders", this.nrOfOrders));
+		logger.info(MessageFormat.format("Loaded {0} Resources", this.nrOfResources));
+		logger.info(MessageFormat.format("Loaded {0} Activities", this.nrOfActivities));
+	}
+
+	private <T extends StrolchRootElement> void loadElements(String context,
+			Function<StrolchTransaction, StrolchDao<T>> daoSupplier, Supplier<CachedElementMap<T>> elementMapSupplier,
+			AtomicLong counter) {
+
+		long start = System.nanoTime();
+		long nrOfElements;
+		CachedElementMap<T> elementMap = elementMapSupplier.get();
+
+		try (StrolchTransaction tx = this.realm.openTx(getCert(), "strolch_boot_" + context, false)) {
+			StrolchDao<T> dao = daoSupplier.apply(tx);
+			nrOfElements = dao.querySize();
+			logger.info("Loading " + nrOfElements + " " + context + " from DB...");
+
+			Set<String> types = dao.queryTypes();
+			for (String type : types) {
+				long sizeOfType = dao.querySize(type);
+				logger.info("Loading " + sizeOfType + " " + context + " of type " + type + " from DB...");
+
+				List<T> elements = dao.queryAll(type);
+				elementMap.insertAll(elements);
+				counter.addAndGet(elements.size());
+			}
+
+			tx.commitOnClose();
+		}
+
+		String durationS = StringHelper.formatNanoDuration(System.nanoTime() - start);
+		logger.info(MessageFormat.format("Loading of {0} {1} took {2}.", nrOfElements, context, durationS));
+	}
+
+	private <T extends StrolchRootElement> void loadElementsPagingAsync(String context,
+			Function<StrolchTransaction, StrolchDao<T>> daoSupplier, Supplier<CachedElementMap<T>> elementMapSupplier,
+			AtomicLong counter) {
+
+		long start = System.nanoTime();
+
+		Map<String, Long> sizeByTypes = getSizesByType(daoSupplier);
+		CachedElementMap<T> elementMap = elementMapSupplier.get();
+
+		long nrOfElements = sizeByTypes.values().stream().mapToLong(Long::longValue).sum();
+		logger.info("Loading " + nrOfElements + " " + context + " from DB...");
+
+		List<CompletableFuture<List<T>>> tasks = new ArrayList<>();
+		sizeByTypes.keySet().stream().sorted(Comparator.comparing(sizeByTypes::get)).forEach(type -> {
+			long size = sizeByTypes.get(type);
+			if (size < MIN_PAGE_SIZE) {
+				logger.info("Loading " + size + " " + context + " of type " + type + " from DB async in parallel...");
+				tasks.add(supplyAsync(() -> loadPage(daoSupplier, type, MAX_VALUE, 0)));
+			} else {
+				long pageSize = Math.max(MIN_PAGE_SIZE, size / Runtime.getRuntime().availableProcessors());
+				logger.info("Loading " + size + " " + context + " of type " + type + " in pages of " + pageSize
+						+ " from DB async in parallel...");
+				long position = 0;
+				while (position < size) {
+					long offset = position;
+					tasks.add(supplyAsync(() -> loadPage(daoSupplier, type, pageSize, offset)));
+					position += pageSize;
+				}
+			}
+		});
+
+		// wait for all tasks to complete
+		Throwable failureEx = allOf(tasks.toArray(new CompletableFuture[0])).handle((u, t) -> t).join();
+		if (failureEx != null)
+			throw new IllegalStateException("Failed to load " + context, failureEx);
+
+		// now insert elements into element map
+		tasks.stream().map(CompletableFuture::join).forEach(elements -> {
+			elementMap.insertAll(elements);
+			counter.addAndGet(elements.size());
+		});
+
+		DBC.POST.assertEquals("Expected size should be same as counter", nrOfElements, counter.get());
+		String durationS = StringHelper.formatNanoDuration(System.nanoTime() - start);
+		logger.info(MessageFormat.format("Loading of {0} {1} took {2}.", counter, context, durationS));
+	}
+
+	private <T extends StrolchRootElement> List<T> loadPage(Function<StrolchTransaction, StrolchDao<T>> daoSupplier,
+			String type, long pageSize, long offset) {
+		try (StrolchTransaction tx = this.realm.openTx(getCert(), "strolch_boot", true)
+				.silentThreshold(10, SECONDS)
+				.suppressUpdates()) {
+			return daoSupplier.apply(tx).queryAll(pageSize, offset, type);
+		}
+	}
+
+	private <T extends StrolchRootElement> Map<String, Long> getSizesByType(
+			Function<StrolchTransaction, StrolchDao<T>> daoSupplier) {
+		Map<String, Long> sizeByTypes = new HashMap<>();
+		try (StrolchTransaction tx = this.realm.openTx(getCert(), "strolch_boot", true).silentThreshold(10, SECONDS)) {
+			StrolchDao<T> dao = daoSupplier.apply(tx);
+			Set<String> types = dao.queryTypes();
+			for (String type : types) {
+				sizeByTypes.put(type, dao.querySize(type));
+			}
+		}
+		return sizeByTypes;
+	}
+
+	private Certificate getCert() {
+		return this.privilegeContext.getCertificate();
+	}
+}

li.strolch.agent/src/main/java/li/strolch/agent/impl/InternalStrolchRealm.java

@@ -44,6 +44,7 @@ public abstract class InternalStrolchRealm implements StrolchRealm {
 	private boolean versioningEnabled;
 	private boolean updateObservers;
 	private ObserverHandler observerHandler;
+
 	protected ComponentContainer container;
 
 	public InternalStrolchRealm(String realm) {

li.strolch.agent/src/main/java/li/strolch/agent/impl/TransientElementMap.java

@@ -244,11 +244,14 @@ public abstract class TransientElementMap<T extends StrolchRootElement> implemen
 	 * Special method used when starting the container to cache the values. Not to be used anywhere else but from the
 	 * {@link CachedRealm}
 	 *
-	 * @param element
-	 * 		the element to insert
+	 * @param elements
+	 * 		the elements to insert
 	 */
-	synchronized void insert(T element) {
+	synchronized void insertAll(List<T> elements) {
+		elements.forEach(this::internalInsert);
+	}
 
+	private void internalInsert(T element) {
 		Map<String, T> byType = this.elementMap.computeIfAbsent(element.getType(), k -> new HashMap<>());
 
 		// assert no object already exists with this id
@@ -274,19 +277,7 @@ public abstract class TransientElementMap<T extends StrolchRootElement> implemen
 		if (!element.hasVersion())
 			Version.setInitialVersionFor(element, tx.getCertificate().getUsername());
 
-		Map<String, T> byType = this.elementMap.computeIfAbsent(element.getType(), k -> new HashMap<>());
-
-		// assert no object already exists with this id
-		if (byType.containsKey(element.getId())) {
-			String msg = "An element already exists with the id \"{0}\". Elements of the same class must always have a unique id, regardless of their type!"; //$NON-NLS-1$
-			msg = MessageFormat.format(msg, element.getId());
-			throw new StrolchPersistenceException(msg);
-		}
-
-		byType.put(element.getId(), element);
-
-		// now make read only
-		element.setReadOnly();
+		internalInsert(element);
 	}
 
 	@Override

li.strolch.agent/src/main/java/li/strolch/persistence/api/AbstractTransaction.java

@@ -233,6 +233,12 @@ public abstract class AbstractTransaction implements StrolchTransaction {
 		return TimeUnit.NANOSECONDS.toMillis(this.silentThreshold);
 	}
 
+	@Override
+	public StrolchTransaction suppressUpdates() {
+		this.suppressUpdates = true;
+		return this;
+	}
+
 	@Override
 	public void setSuppressUpdates(boolean suppressUpdates) {
 		this.suppressUpdates = suppressUpdates;

li.strolch.agent/src/main/java/li/strolch/persistence/api/PersistenceHandler.java

@@ -27,6 +27,11 @@ import li.strolch.privilege.model.Certificate;
  */
 public interface PersistenceHandler {
 
+	/**
+	 * Returns true if this persistence layer supports paging, i.e. the DAO methods with a limit and offset may be used
+	 */
+	boolean supportsPaging();
+
 	/**
 	 * Opens a {@link StrolchTransaction} on the given {@link StrolchRealm}. The transaction is the main object to be
 	 * used when accessing and modifying the elements of a realm.

li.strolch.agent/src/main/java/li/strolch/persistence/api/StrolchTransaction.java

@@ -206,9 +206,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	long getActivityCount(String type);
 
 	/**
-	 * Returns the {@link PersistenceHandler}. If the {@link StrolchRealm} is not running in {@link
-	 * DataStoreMode#TRANSIENT} mode, then the {@link PersistenceHandler} will be a {@link StrolchComponent}, otherwise
-	 * it will be the internal in memory persistence handler
+	 * Returns the {@link PersistenceHandler}. If the {@link StrolchRealm} is not running in
+	 * {@link DataStoreMode#TRANSIENT} mode, then the {@link PersistenceHandler} will be a {@link StrolchComponent},
+	 * otherwise it will be the internal in memory persistence handler
 	 *
 	 * @return the {@link PersistenceHandler}
 	 */
@@ -332,8 +332,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 * <p>
 	 * <code>
-	 * StrolchAgent strolchAgent = getStrolchAgent(); StrolchRealm realm = strolchAgent.getContainer().getRealm("defaultRealm");
-	 * try(StrolchTransaction tx = realm.openTx(certificate, getClass())){ // do work tx.commitOnClose(); }
+	 * StrolchAgent strolchAgent = getStrolchAgent(); StrolchRealm realm =
+	 * strolchAgent.getContainer().getRealm("defaultRealm"); try(StrolchTransaction tx = realm.openTx(certificate,
+	 * getClass())){ // do work tx.commitOnClose(); }
 	 * </code>
 	 * <p>
 	 * After the block is closed, the transaction is automatically closed and all allocated resources are released
@@ -362,8 +363,8 @@ public interface StrolchTransaction extends AutoCloseable {
 	StrolchTransaction rollbackOnClose();
 
 	/**
-	 * Sets the {@link TransactionCloseStrategy} to {@link TransactionCloseStrategy#ROLLBACK} and returns a {@link
-	 * StrolchTransactionException} which can be thrown by the caller to stop the exception
+	 * Sets the {@link TransactionCloseStrategy} to {@link TransactionCloseStrategy#ROLLBACK} and returns a
+	 * {@link StrolchTransactionException} which can be thrown by the caller to stop the exception
 	 *
 	 * @param exceptionMessage
 	 * 		the message with which this TX has failed
@@ -407,7 +408,8 @@ public interface StrolchTransaction extends AutoCloseable {
 	boolean isOpen();
 
 	/**
-	 * @return if the current state of the StrolchTransaction is {@link TransactionCloseStrategy#READ_ONLY} or {@link TransactionCloseStrategy#ROLLBACK}
+	 * @return if the current state of the StrolchTransaction is {@link TransactionCloseStrategy#READ_ONLY} or
+	 * {@link TransactionCloseStrategy#ROLLBACK}
 	 */
 	boolean isReadOnly();
 
@@ -458,6 +460,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 */
 	long getSilentThreshold();
 
+	/**
+	 * Suppresses the updates of observer
+	 */
+	StrolchTransaction suppressUpdates();
+
 	/**
 	 * If the given argument is true, then no observer updates are performed
 	 *
@@ -597,8 +604,8 @@ public interface StrolchTransaction extends AutoCloseable {
 	void add(Command command);
 
 	/**
-	 * Helper method to create an {@link Audit} with the given arguments. The audit can then be saved by calling {@link
-	 * AuditTrail#add(StrolchTransaction, Audit)}
+	 * Helper method to create an {@link Audit} with the given arguments. The audit can then be saved by calling
+	 * {@link AuditTrail#add(StrolchTransaction, Audit)}
 	 *
 	 * @param accessType
 	 * 		the type of access
@@ -614,8 +621,8 @@ public interface StrolchTransaction extends AutoCloseable {
 	Audit auditFrom(AccessType accessType, String elementType, String elementSubType, String id);
 
 	/**
-	 * Helper method to create an {@link Audit} with the given arguments. The audit can then be saved by calling {@link
-	 * AuditTrail#add(StrolchTransaction, Audit)}
+	 * Helper method to create an {@link Audit} with the given arguments. The audit can then be saved by calling
+	 * {@link AuditTrail#add(StrolchTransaction, Audit)}
 	 *
 	 * @param accessType
 	 * 		the type of access
@@ -649,8 +656,8 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * This method can also be used to find a deeper element, e.g. a specific {@link Parameter} on an {@link
-	 * ParameterBag} on an {@link Order}. This would be done as follows: <i>Order/MyType/Bag/@1/myParam</i>
+	 * This method can also be used to find a deeper element, e.g. a specific {@link Parameter} on an
+	 * {@link ParameterBag} on an {@link Order}. This would be done as follows: <i>Order/MyType/Bag/@1/myParam</i>
 	 * </p>
 	 *
 	 * @param locator
@@ -673,8 +680,8 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * <p>Finds a parameter with the {@link StrolchConstants#BAG_PARAMETERS} and @paramKey on the given @element, but
-	 * if it does not exists on the element, then it retrieves the elements parent by using the bag {@link
-	 * StrolchModelConstants#BAG_RELATIONS} and the param @parentParamKey.</p>
+	 * if it does not exists on the element, then it retrieves the elements parent by using the bag
+	 * {@link StrolchModelConstants#BAG_RELATIONS} and the param @parentParamKey.</p>
 	 *
 	 * <p>In Strolch relationships are usually defined on the parameter bag with the id {@link
 	 * StrolchModelConstants#BAG_RELATIONS}</p>
@@ -693,8 +700,8 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * <p>Finds a parameter with the given @bagKey and @paramKey on the given @element, but if it does not exists
-	 * on the element, then it retrieves the elements parent by using the bag {@link
-	 * StrolchModelConstants#BAG_RELATIONS} and the param @parentParamKey.</p>
+	 * on the element, then it retrieves the elements parent by using the bag
+	 * {@link StrolchModelConstants#BAG_RELATIONS} and the param @parentParamKey.</p>
 	 *
 	 * <p>In Strolch relationships are usually defined on the parameter bag with the id {@link
 	 * StrolchModelConstants#BAG_RELATIONS}</p>
@@ -750,10 +757,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating a {@link Resource} of type {@code Person} then having a template with the id {@code Person} helps
-	 * creating new Person resources; get the resource and then create a clone: {@link Resource#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating a {@link Resource} of type {@code Person} then having a template with the id
+	 * {@code Person} helps creating new Person resources; get the resource and then create a clone:
+	 * {@link Resource#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -770,10 +778,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating a {@link Resource} of type {@code Person} then having a template with the id {@code Person} helps
-	 * creating new Person resources; get the resource and then create a clone: {@link Resource#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating a {@link Resource} of type {@code Person} then having a template with the id
+	 * {@code Person} helps creating new Person resources; get the resource and then create a clone:
+	 * {@link Resource#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -820,10 +829,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating an {@link Order} of type {@code PurchaseOrder} then having a template with the id {@code PurchaseOrder}
-	 * helps creating new PurchaseOrder orders; get the order and then create a clone: {@link Order#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating an {@link Order} of type {@code PurchaseOrder} then having a template with the id
+	 * {@code PurchaseOrder} helps creating new PurchaseOrder orders; get the order and then create a clone:
+	 * {@link Order#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -840,10 +850,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating an {@link Order} of type {@code PurchaseOrder} then having a template with the id {@code PurchaseOrder}
-	 * helps creating new PurchaseOrder orders; get the order and then create a clone: {@link Order#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating an {@link Order} of type {@code PurchaseOrder} then having a template with the id
+	 * {@code PurchaseOrder} helps creating new PurchaseOrder orders; get the order and then create a clone:
+	 * {@link Order#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -864,10 +875,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating a {@link Activity} of type {@code ToStock} then having a template with the id {@code ToStock} helps
-	 * creating new ToStock activities; get the activity and then create a clone: {@link Activity#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating a {@link Activity} of type {@code ToStock} then having a template with the id
+	 * {@code ToStock} helps creating new ToStock activities; get the activity and then create a clone:
+	 * {@link Activity#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -884,10 +896,11 @@ public interface StrolchTransaction extends AutoCloseable {
 	 * </p>
 	 *
 	 * <p>
-	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type {@link
-	 * StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For instance when
-	 * creating a {@link Activity} of type {@code ToStock} then having a template with the id {@code ToStock} helps
-	 * creating new ToStock activities; get the activity and then create a clone: {@link Activity#getClone()}
+	 * Templates are {@link StrolchRootElement StrolchRootElements} which have the type
+	 * {@link StrolchModelConstants#TEMPLATE} and their id is the type of element for which it is a template. For
+	 * instance when creating a {@link Activity} of type {@code ToStock} then having a template with the id
+	 * {@code ToStock} helps creating new ToStock activities; get the activity and then create a clone:
+	 * {@link Activity#getClone()}
 	 * </p>
 	 *
 	 * @param type
@@ -931,9 +944,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	Resource getResourceBy(String type, String id, boolean assertExists) throws StrolchException;
 
 	/**
-	 * Returns the {@link Resource} which is referenced by the given {@link StringParameter}. A reference {@link
-	 * Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the
-	 * UOM must be set to the resource's type and the value is the id of the resource
+	 * Returns the {@link Resource} which is referenced by the given {@link StringParameter}. A reference
+	 * {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF}
+	 * and the UOM must be set to the resource's type and the value is the id of the resource
 	 *
 	 * @param refP
 	 * 		the {@link StringParameter} which references a {@link Resource}
@@ -946,9 +959,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	Resource getResourceBy(StringParameter refP) throws StrolchException;
 
 	/**
-	 * Returns the {@link Resource} which is referenced by the given {@link StringParameter}. A reference {@link
-	 * Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the
-	 * UOM must be set to the resource's type and the value is the id of the resource
+	 * Returns the {@link Resource} which is referenced by the given {@link StringParameter}. A reference
+	 * {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF}
+	 * and the UOM must be set to the resource's type and the value is the id of the resource
 	 *
 	 * @param refP
 	 * 		the {@link StringParameter} which references a {@link Resource}
@@ -1000,16 +1013,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Resource} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the value
-	 * is the id of the resource to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the
+	 * value is the id of the resource to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Resource} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the resource referenced by the element, or null if the {@link ParameterBag}, {@link StringParameter} or
 	 * referenced element do not exist
@@ -1022,16 +1035,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Resource} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the value
-	 * is the id of the resource to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the
+	 * value is the id of the resource to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Resource} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced resource does not exist, then a {@link StrolchException} is thrown
 	 *
@@ -1046,17 +1059,17 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Resource Resources} which are referenced by the given {@link StrolchRootElement}. The element
-	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the value
-	 * is the id of the resource to return
+	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the
+	 * value is the id of the resource to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Resource} through a {@link StringListParameter} with
 	 * 		the given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the resources referenced by the element, or null if the {@link ParameterBag}, {@link StringListParameter}
 	 * or referenced element do not exist
@@ -1068,17 +1081,17 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Resource Resources} which are referenced by the given {@link StrolchRootElement}. The element
-	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the value
-	 * is the id of the resource to return
+	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_RESOURCE_REF} and the UOM must be set to the resource's type and the
+	 * value is the id of the resource to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Resource} through a {@link StringListParameter} with
 	 * 		the given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced resource does not exist, then a {@link StrolchException} is thrown
 	 *
@@ -1155,9 +1168,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	Activity getActivityBy(String type, String id, boolean assertExists) throws StrolchException;
 
 	/**
-	 * Returns the {@link Activity} which is referenced by the given {@link StringParameter}. A reference {@link
-	 * Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the
-	 * UOM must be set to the activity's type and the value is the id of the activity
+	 * Returns the {@link Activity} which is referenced by the given {@link StringParameter}. A reference
+	 * {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF}
+	 * and the UOM must be set to the activity's type and the value is the id of the activity
 	 *
 	 * @param refP
 	 * 		the {@link StringParameter} which references an {@link Activity}
@@ -1170,9 +1183,9 @@ public interface StrolchTransaction extends AutoCloseable {
 	Activity getActivityBy(StringParameter refP) throws StrolchException;
 
 	/**
-	 * Returns the {@link Activity} which is referenced by the given {@link StringParameter}. A reference {@link
-	 * Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the
-	 * UOM must be set to the activity's type and the value is the id of the activity
+	 * Returns the {@link Activity} which is referenced by the given {@link StringParameter}. A reference
+	 * {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF}
+	 * and the UOM must be set to the activity's type and the value is the id of the activity
 	 *
 	 * @param refP
 	 * 		the {@link StringParameter} which references an {@link Activity}
@@ -1189,8 +1202,9 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Activity Activities} which are referenced by the given {@link StringListParameter}. A
-	 * reference {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF}
-	 * and the UOM must be set to the activity's type and the value is the id of the activity
+	 * reference {@link Parameter} must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * value is the id of the activity
 	 *
 	 * @param refP
 	 * 		the {@link StringListParameter} which references a list of {@link Activity Activities}
@@ -1205,8 +1219,9 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Activity Activities} which are referenced by the given {@link StringListParameter}. A
-	 * reference {@link Parameter} must have its interpretation set to {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF}
-	 * and the UOM must be set to the activity's type and the value is the id of the activity
+	 * reference {@link Parameter} must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * value is the id of the activity
 	 *
 	 * @param refP
 	 * 		the {@link StringListParameter} which references a list of {@link Activity Activities}
@@ -1224,16 +1239,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Activity} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the value
-	 * is the id of the activity to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * value is the id of the activity to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Activity} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the activity referenced by the element, or null if the {@link ParameterBag}, {@link StringParameter} or
 	 * referenced element do not exist
@@ -1246,16 +1261,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Activity} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the value
-	 * is the id of the activity to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * value is the id of the activity to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Activity} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced order does not exist, then a {@link StrolchException} is thrown
 	 *
@@ -1270,17 +1285,17 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Activity Activities} which are referenced by the given {@link StrolchRootElement}. The element
-	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the values
-	 * are the ids of the activities to return
+	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * values are the ids of the activities to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Activity} through a {@link StringListParameter} with
 	 * 		the given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the activity referenced by the element, or null if the {@link ParameterBag}, {@link StringListParameter}
 	 * or referenced element do not exist
@@ -1292,22 +1307,22 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Activity Activities} which are referenced by the given {@link StrolchRootElement}. The element
-	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the values
-	 * are the ids of the activities to return
+	 * must have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ACTIVITY_REF} and the UOM must be set to the activity's type and the
+	 * values are the ids of the activities to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Activity} through a {@link StringListParameter} with
 	 * 		the given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced order does not exist, then a {@link StrolchException} is thrown
 	 *
-	 * @return the activities referenced by the element, or null if the {@link ParameterBag}, {@link
-	 * StringListParameter} or referenced element do not exist
+	 * @return the activities referenced by the element, or null if the {@link ParameterBag},
+	 * {@link StringListParameter} or referenced element do not exist
 	 *
 	 * @throws StrolchException
 	 * 		if the {@link StringListParameter} is not a properly configured as a reference parameter
@@ -1414,16 +1429,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Order} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the value is the
-	 * id of the order to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the value
+	 * is the id of the order to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Order} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the order referenced by the element, or null if the {@link ParameterBag}, {@link StringParameter} or
 	 * referenced element do not exist
@@ -1436,16 +1451,16 @@ public interface StrolchTransaction extends AutoCloseable {
 	/**
 	 * Returns the {@link Order} which is referenced by the given {@link StrolchRootElement}. The element must have a
 	 * {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link StringParameter} on it
-	 * with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the value is the
-	 * id of the order to return
+	 * with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the value
+	 * is the id of the order to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Order} through a {@link StringParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced order does not exist, then a {@link StrolchException} is thrown
 	 *
@@ -1459,17 +1474,17 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Order Orders} which are referenced by the given {@link StrolchRootElement}. The element must
-	 * have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the values are
-	 * the ids of the orders to return
+	 * have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the values
+	 * are the ids of the orders to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Order} through a {@link StringListParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 *
 	 * @return the orders referenced by the element, or null if the {@link ParameterBag}, {@link StringListParameter} or
 	 * referenced element do not exist
@@ -1481,17 +1496,17 @@ public interface StrolchTransaction extends AutoCloseable {
 
 	/**
 	 * Returns all {@link Order Orders} which are referenced by the given {@link StrolchRootElement}. The element must
-	 * have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a {@link
-	 * StringListParameter} on it with the given refId. The parameter must have its interpretation set to {@link
-	 * StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the values are
-	 * the ids of the orders to return
+	 * have a {@link ParameterBag} with the id {@link StrolchModelConstants#BAG_RELATIONS} and a
+	 * {@link StringListParameter} on it with the given refId. The parameter must have its interpretation set to
+	 * {@link StrolchModelConstants#INTERPRETATION_ORDER_REF} and the UOM must be set to the order's type and the values
+	 * are the ids of the orders to return
 	 *
 	 * @param element
 	 * 		the {@link StrolchRootElement} which references a {@link Order} through a {@link StringListParameter} with the
 	 * 		given refId
 	 * @param refId
-	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id {@link
-	 *        StrolchModelConstants#BAG_RELATIONS}
+	 * 		the id of the {@link StringListParameter} which needs to be on the {@link ParameterBag} with the id
+	 *        {@link StrolchModelConstants#BAG_RELATIONS}
 	 * @param assertExists
 	 * 		if true, and referenced order does not exist, then a {@link StrolchException} is thrown
 	 *

li.strolch.persistence.postgresql/src/main/java/li/strolch/persistence/postgresql/PostgreSqlPersistenceHandler.java

@@ -55,6 +55,11 @@ public class PostgreSqlPersistenceHandler extends StrolchComponent implements Pe
 		super(container, componentName);
 	}
 
+	@Override
+	public boolean supportsPaging() {
+		return true;
+	}
+
 	public DataType getDataType() {
 		return this.dataType;
 	}
@@ -93,8 +98,8 @@ public class PostgreSqlPersistenceHandler extends StrolchComponent implements Pe
 		boolean allowSchemaCreation = configuration.getBoolean(PROP_ALLOW_SCHEMA_CREATION, Boolean.FALSE);
 		boolean allowSchemaMigration = configuration.getBoolean(PROP_ALLOW_SCHEMA_MIGRATION, Boolean.FALSE);
 		boolean allowSchemaDrop = configuration.getBoolean(PROP_ALLOW_SCHEMA_DROP, Boolean.FALSE);
-		boolean allowDataInitOnSchemaCreate = configuration
-				.getBoolean(PROP_ALLOW_DATA_INIT_ON_SCHEMA_CREATE, Boolean.FALSE);
+		boolean allowDataInitOnSchemaCreate = configuration.getBoolean(PROP_ALLOW_DATA_INIT_ON_SCHEMA_CREATE,
+				Boolean.FALSE);
 
 		DbSchemaVersionCheck schemaVersionCheck = new DbSchemaVersionCheck(SCRIPT_PREFIX_STROLCH, this.getClass(),
 				allowSchemaCreation, allowSchemaMigration, allowSchemaDrop);
@@ -140,8 +145,8 @@ public class PostgreSqlPersistenceHandler extends StrolchComponent implements Pe
 	public Connection getConnection(String realm) {
 		DataSource ds = this.dsMap.get(realm);
 		if (ds == null) {
-			String msg = MessageFormat
-					.format("There is no DataSource registered for the realm {0}", realm); //$NON-NLS-1$
+			String msg = MessageFormat.format("There is no DataSource registered for the realm {0}",
+					realm); //$NON-NLS-1$
 			throw new StrolchPersistenceException(msg);
 		}
 

li.strolch.persistence.xml/src/main/java/li/strolch/persistence/xml/XmlPersistenceHandler.java

@@ -27,13 +27,13 @@ import li.strolch.agent.api.RealmHandler;
 import li.strolch.agent.api.StrolchComponent;
 import li.strolch.agent.api.StrolchRealm;
 import li.strolch.agent.impl.StoreToDaoElementListener;
-import li.strolch.model.log.LogMessage;
 import li.strolch.model.ModelStatistics;
 import li.strolch.model.Order;
 import li.strolch.model.Resource;
 import li.strolch.model.Tags;
 import li.strolch.model.activity.Activity;
 import li.strolch.model.audit.Audit;
+import li.strolch.model.log.LogMessage;
 import li.strolch.model.xml.XmlModelSaxFileReader;
 import li.strolch.persistence.api.*;
 import li.strolch.persistence.xml.model.*;
@@ -60,6 +60,11 @@ public class XmlPersistenceHandler extends StrolchComponent implements Persisten
 		super(container, componentName);
 	}
 
+	@Override
+	public boolean supportsPaging() {
+		return false;
+	}
+
 	@Override
 	public void initialize(ComponentConfiguration configuration) throws Exception {
 
@@ -140,8 +145,8 @@ public class XmlPersistenceHandler extends StrolchComponent implements Persisten
 				logger.info("Initializing realm " + realmName + " as DB is empty.");
 
 				StrolchConfiguration strolchConfiguration = getContainer().getAgent().getStrolchConfiguration();
-				ComponentConfiguration realmConfiguration = strolchConfiguration
-						.getComponentConfiguration(RealmHandler.class.getSimpleName());
+				ComponentConfiguration realmConfiguration = strolchConfiguration.getComponentConfiguration(
+						RealmHandler.class.getSimpleName());
 				String dataStoreKey = makeRealmKey(realmName, PREFIX_DATA_STORE_FILE);
 				RuntimeConfiguration runtimeConfiguration = strolchConfiguration.getRuntimeConfiguration();
 				File dataStoreF = realmConfiguration.getDataFile(dataStoreKey, null, runtimeConfiguration, true);