[client] Image/Lectures: only push metadata/permissions if they were changed

1 files changed, 41 insertions, 0 deletions

diff --git a/dozentenmodul/src/main/java/org/openslx/dozmod/util/MapHelper.java b/dozentenmodul/src/main/java/org/openslx/dozmod/util/MapHelper.java
new file mode 100644
index 00000000..e99b1aa6
--- /dev/null
+++ b/dozentenmodul/src/main/java/org/openslx/dozmod/util/MapHelper.java
@@ -0,0 +1,41 @@
+package org.openslx.dozmod.util;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.apache.log4j.Logger;
+
+public class MapHelper {
+
+	private static final Logger LOGGER = Logger.getLogger(MapHelper.class);
+
+	private MapHelper() {}
+
+	public static <T> boolean hasChanged(final Map<String, T> oldMap, final Map<String, T> newMap) {
+		// build list of users that were added, if any return true
+		if (oldMap.size() != newMap.size())
+			return true;
+
+		// no changes in the users, lets check for changes in each users permissions
+		for (Entry<String, T> entry : oldMap.entrySet()) {
+			T current = entry.getValue();
+			T other = newMap.get(entry.getKey());
+			if (!current.equals(other))
+				return true;
+		}
+		// everything was the same if we are still here
+		return false;
+	}
+	private static <T> Set<String> getAddedUsers(final Map<String, T> oldMap, final Map<String, T> newMap) {
+		Set<String> addedUsers = new HashSet<String>(newMap.keySet());
+		addedUsers.removeAll(oldMap.keySet());
+		return addedUsers;
+	}
+	private static <T> Set<String> getRemovedUsers(final Map<String, T> oldMap, final Map<String, T> newMap) {
+		Set<String> removedUsers = new HashSet<String>(oldMap.keySet());
+		removedUsers.removeAll(newMap.keySet());
+		return removedUsers;
+	}
+}