[Minor] Code cleanup

model/src/main/java/li/strolch/model/AbstractStrolchElement.java

@@ -142,15 +142,10 @@ public abstract class AbstractStrolchElement implements StrolchElement {
 
 	@Override
 	public boolean equals(Object obj) {
-		if (this == obj) {
+		if (this == obj)
 			return true;
-		}
-		if (obj == null) {
+		if (obj == null || getClass() != obj.getClass())
 			return false;
-		}
-		if (getClass() != obj.getClass()) {
-			return false;
-		}
 		AbstractStrolchElement other = (AbstractStrolchElement) obj;
 		if (this.id == null) {
 			return other.id == null;

model/src/main/java/li/strolch/model/Order.java

@@ -292,6 +292,16 @@ public class Order extends AbstractStrolchRootElement implements StrolchRootElem
 		return visitor.visitOrder(this);
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null || getClass() != obj.getClass())
+			return false;
+		Order o = (Order) obj;
+		return this.type.equals(o.type) && this.id.equals(o.id);
+	}
+
 	@Override
 	public String toString() {
 

model/src/main/java/li/strolch/model/Resource.java

@@ -380,6 +380,16 @@ public class Resource extends AbstractStrolchRootElement implements StrolchRootE
 		return visitor.visitResource(this);
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null || getClass() != obj.getClass())
+			return false;
+		Resource r = (Resource) obj;
+		return this.type.equals(r.type) && this.id.equals(r.id);
+	}
+
 	@Override
 	public String toString() {
 

model/src/main/java/li/strolch/model/activity/Activity.java

@@ -766,6 +766,16 @@ public class Activity extends AbstractStrolchRootElement
 		return this;
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null || getClass() != obj.getClass())
+			return false;
+		Activity a = (Activity) obj;
+		return this.parent == a.parent && this.type.equals(a.type) && this.id.equals(a.id);
+	}
+
 	@Override
 	public String toString() {
 		final StringBuilder builder = new StringBuilder();