code: public boolean containsAll(Collection<?> coll) {
          for( Object item : coll ) {
              if( !contains(item) ) {
                  return false;
              }
          }
          return true;
      }
docs: Checks the passed in collection and determines if all elements
  of that collection are contained within this cache. Care should
  be taken in reading too much into a failure. If one of the elements
  was once in this cache but has expired due to inactivity, this
  method will return false.
  @param coll the collection to test
  @return true if all elements of the tested collection are in the cache