code: public static <T> T withinTx(
  			AdvancedCache cache,
  			Callable<T> c) throws Exception {
  		// Retrieve transaction manager
  		return withinTx( cache.getTransactionManager(), c );
  	}
docs: Call an operation within a transaction. This method guarantees that the
  right pattern is used to make sure that the transaction is always either
  committed or rollback.
  
  @param cache instance whose transaction manager to use
  @param c callable instance to run within a transaction
  @param <T> type of callable return
  @return returns whatever the callable returns
  @throws Exception if any operation within the transaction fails