@Override
 public boolean serialize(final ByteBuffer buffer) {
   if (this.contents.size() > 65535) {
     return false;
   }
   buffer.putShort((short) this.contents.size());
   for (int i = 0; i < this.contents.size(); ++i) {
     final Content contents_element = this.contents.get(i);
     final boolean contents_element_ok = contents_element.serialize(buffer);
     if (!contents_element_ok) {
       return false;
     }
   }
   if (this.contentsSelection != null) {
     buffer.put((byte) 1);
     final boolean contentsSelection_ok = this.contentsSelection.serialize(buffer);
     if (!contentsSelection_ok) {
       return false;
     }
   } else {
     buffer.put((byte) 0);
   }
   if (this.buyableContents.size() > 65535) {
     return false;
   }
   buffer.putShort((short) this.buyableContents.size());
   for (int i = 0; i < this.buyableContents.size(); ++i) {
     final BuyableContent buyableContents_element = this.buyableContents.get(i);
     final boolean buyableContents_element_ok = buyableContents_element.serialize(buffer);
     if (!buyableContents_element_ok) {
       return false;
     }
   }
   return true;
 }
 @Override
 public boolean serialize(final ByteBuffer buffer) {
   if (this.gems.size() > 65535) {
     return false;
   }
   buffer.putShort((short) this.gems.size());
   for (int i = 0; i < this.gems.size(); ++i) {
     final Content gems_element = this.gems.get(i);
     final boolean gems_element_ok = gems_element.serialize(buffer);
     if (!gems_element_ok) {
       return false;
     }
   }
   return true;
 }