java中的CRUD操作模板

Question

I'm designing a system where I must perform several CRUD operations among the System entities. Just for make sure I searched in forums to see how it's resolved by someone else.

I found 4 "patterns" . All of them agree in the READ operations so I skip them. I'll define the patterns:

Pattern 1

void add(E entity);
void update(E entity);
// Read operations...
void delete(E entity);

Pattern 2

E create(<ListOfEntityProperties>);
void update(E entity);
// Read operations...
void delete(E entity);

Pattern 3

boolean add(E entity);
boolean update(E entity);
// Read operations...
boolean delete(E entity);

Pattern 4

E add(E entity);
void update(E entity);
// Read operations...
void delete(E entity);

I don't understand the difference and advantages/disadvantages of each one (and no one explains it). What are the differences between each "pattern" ? What criteria to use? Can someone justify when to use one way or another (or give me another idea)?

Thanks in advance for your answers

Answer 1

Take Pattern 3, for example, you'd use a boolean to know if something successfully was deleted or added. The deleted case is okay, but for the added or updated case, you might want the object back with a database assigned id, which looks like pattern 4.

If you want to batch insert objects, then that's pattern 2.

And if you don't expect to return anything from a CRUD operation, then make the methods void .

The values that you want returned are the important part, the "patterns" don't matter so much, and they completely depend on the underlying API usage. For example, a SQL Server insert operation may return the row ID of the inserted object. In that case, you could return just the ID, or the same object you passed as a parameter, but with its ID field set.

Answer 2

Jut asking , why do you want to write\\design your own implementations. I used java-ee annotation for this.

references: https://docs.oracle.com/javaee/6/api/javax/ws/rs/package-summary.html http://www.techferry.com/articles/RESTful-web-services-JAX-RS-annotations.html

You can refer their implementations too.