1. (2.5 pts) A company provides online ordering services. A customer needs to request a service object in order to place an order. In the past, the business was slow so that the system ran well. Today, the business is soaring and the system often fails due to insufficient memory. Before new hardware is acquired, the company would like you to redesign the system to prevent the problem. Which design pattern is a good candidate? 2. (2.5 pts) A simulation takes several days to process big data and stores the computed results in an object. Some subsequent experiments need to utilize the results of this object. Knowing that every experiment is likely to change the contents of the object, which design pattern is a good choice to help run the experiments correctly and independently? 3. (2.5 pts) Design a printer manager to spool all of the submitted printing jobs in order to print them in sequence. Without this printer manager, the printer may print out interleaved results of those submitted job. Which design pattern is a choice for this printer manager? 4. (2.5 pts) Based on your answer to Q3, show the UML class diagram for this printer manager class.