MGR-71 fix possible NPEs when building filters (#16)

src/main/java/org/appng/application/manager/business/PlatformEvents.java

@@ -17,6 +17,7 @@
 
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.List;
@@ -83,7 +84,7 @@ public DataContainer getData(Site site, Application application, Environment env
 
 		selections.add(selectionFactory.getTextSelection(EventFilter.EVENT, MessageConstants.EVENT, filter.getEX()));
 
-		List<String> users = platformEventEventService.getUsers();
+		Collection<String> users = platformEventEventService.getUsers();
 		Selection userSelection;
 		if (users.size() > application.getProperties().getInteger(ManagerSettings.EVENT_FILTER_MAX_USERS)) {
 			String username = StringUtils.trimToEmpty(filter.getEU());
@@ -94,17 +95,17 @@ public DataContainer getData(Site site, Application application, Environment env
 		}
 		selections.add(userSelection);
 
-		List<String> applications = platformEventEventService.getApplications();
+		Collection<String> applications = platformEventEventService.getApplications();
 		Selection applicationSelection = getStringSelection(EventFilter.APP, applications, filter.getEAp(),
 				MessageConstants.APPLICATION);
 		selections.add(applicationSelection);
 
-		List<String> hostNames = platformEventEventService.getOrigins();
+		Collection<String> hostNames = platformEventEventService.getOrigins();
 		Selection hostSelection = getStringSelection(EventFilter.HOST, hostNames, filter.getEH(),
 				MessageConstants.HOST);
 		selections.add(hostSelection);
 
-		List<String> hosts = platformEventEventService.getHostNames();
+		Collection<String> hosts = platformEventEventService.getHostNames();
 		Selection hostNameSelection = getStringSelection(EventFilter.HOSTNAME, hosts, filter.getEN(),
 				MessageConstants.HOST_NAME);
 		selections.add(hostNameSelection);
@@ -122,7 +123,7 @@ public DataContainer getData(Site site, Application application, Environment env
 		return dataContainer;
 	}
 
-	private Selection getStringSelection(String id, List<String> values, String selected, String label) {
+	private Selection getStringSelection(String id, Collection<String> values, String selected, String label) {
 		SelectionBuilder<String> builder = new SelectionBuilder<String>(id);
 		return builder.title(label).options(values).select(selected).type(SelectionType.SELECT)
 				.defaultOption(StringUtils.EMPTY, StringUtils.EMPTY).build();

src/main/java/org/appng/application/manager/service/PlatformEventService.java

@@ -15,7 +15,10 @@
  */
 package org.appng.application.manager.service;
 
+import java.util.Collection;
 import java.util.List;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 import org.apache.commons.lang3.StringUtils;
 import org.appng.application.manager.business.PlatformEvents.EventFilter;
@@ -58,19 +61,25 @@ public List<PlatformEvent> getEvents(EventFilter eventFilter) {
 		return getEvents(new PageRequest(0, Integer.MAX_VALUE), eventFilter).getContent();
 	}
 
-	public List<String> getUsers() {
-		return platformEventRepository.findDistinctUsers();
+	public Collection<String> getUsers() {
+		return removeNulls(platformEventRepository.findDistinctUsers());
 	}
 
-	public List<String> getApplications() {
-		return platformEventRepository.findDistinctApplications();
+	public Collection<String> getApplications() {
+		return removeNulls(platformEventRepository.findDistinctApplications());
 	}
 
-	public List<String> getHostNames() {
-		return platformEventRepository.findDistinctHostNames();
+	public Collection<String> getHostNames() {
+		return removeNulls(platformEventRepository.findDistinctHostNames());
 	}
 
-	public List<String> getOrigins() {
-		return platformEventRepository.findDistinctOrigins();
+	public Collection<String> getOrigins() {
+		return removeNulls(platformEventRepository.findDistinctOrigins());
+	}
+
+	private Collection<String> removeNulls(List<String> items) {
+		SortedSet<String> set = new TreeSet<>(items);
+		set.remove(null);
+		return set;
 	}
 }