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https://github.com/serkan-ozal/spring-jdbc-roma

Spring JDBC extension for object mapping supported rowmapper
https://github.com/serkan-ozal/spring-jdbc-roma

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Spring JDBC extension for object mapping supported rowmapper

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README 

        
## **What is Spring-JDBC-ROMA?**



**Spring-JDBC-ROMA** is a rowmapper extension for **Spring-JDBC module**. 

There is already a rowmapper named **"org.springframework.jdbc.core.BeanPropertyRowMapper"** for binding 

resultset attributes to object. But it is reflection based and can cause performance problems as Spring developers said.

However **Spring-JDBC-ROMA** is not reflection based and it is byte code generation (with **CGLib** and **Javassist**) 

based rowmapper. It generates rowmapper on the fly like implementing as manual so it has no performance overhead. 

It also supports object relations as lazy and eager. There are other lots of interesting features and 

these features can be customized with developer's extended classes. 



## **What features does Spring-JDBC-ROMA have?**



* All primitive types, enums, dates, collections, blob, clob and complex objects are supported.  



* Lazy or eager field accessing is supported.   



* Writing your custom field based **RowMapperFieldGenerator** implementations is supported.   



* Writing your custom class (or type) based **RowMapperFieldGeneratorFactory** implementations is supported. 

  

* Writing field access definitions as compilable Java code in annotation or configuration file (XML file, properties file, ...) is supported.    



## **Install**



In your **pom.xml**, you must add repository and dependency for Spring-JDBC-ROMA. 

You can change **spring.jdbc.roma.version** to any existing **spring-jdbc-roma** library version.



~~~~~ xml

...



    ...

    1.0.0-RELEASE

    ...



...



    ...

	

		org.springframework

		spring-jdbc-roma

		${spring.jdbc.roma.version}

	

	...



...



	...

	

		serkanozal-maven-repository

		https://github.com/serkan-ozal/maven-repository/raw/master/

	

	...



...

~~~~~



And finally, in your **Spring context xml** file add following configuration to make your Spring context automatically aware of Spring-JDBC-ROMA.



~~~~~ xml

...



...

~~~~~



## **Spring-JDBC-ROMA with a simple example**

  

Here is **User** class:  



~~~~~ java

public class User {



    @RowMapperField(columnName = "id")

    private Long id;

    @RowMapperField(columnName = "username")

    private String username;

    @RowMapperField(columnName = "password")

    private String password;

    @RowMapperField(columnName = "firstname")

    private String firstname;

    @RowMapperField(columnName = "lastname")

    private String lastname;

    @RowMapperField(columnName = "enabled")

    private boolean enabled = true;

    @RowMapperField(columnName = "gender")

    private Gender gender;

    @RowMapperObjectField(

        provideViaSpringProvider = 

            @RowMapperSpringProvider(

                provideCode = "@{roleDAO}.getUserRoleList(${id})"),

        lazy = true)

    private List roles = new ArrayList();

    

    ...

    

} 

~~~~~



Here is **Role** class:    



~~~~~ java

public class Role {



    @RowMapperField(columnName = "id")

    private Long id;

    @RowMapperField(columnName = "name")

    private String name;

    @RowMapperObjectField(

        provideViaSpringProvider = 

            @RowMapperSpringProvider(

                provideCode = "@{permissionDAO}.getRolePermissionList(${id})"),

        lazy = true)

    private List permissions = new ArrayList();



    ...

    

}

~~~~~

	

You can get **User** entity rowmapper as follows:



~~~~~ java

@Autowired

RowMapperService rowMapperService;

    

...



RowMapper userRowMapper = rowMapperService.getRowMapper(User.class);

~~~~~



In this example, we can get related **Role** entites of **User** entity with **"@RowMapperObjectField"** annotion automatically. 

We use **"@RowMapperObjectField"** annotation for accessing related **Role** entites of **User** entity with **id** attribute of User. 

We have **"lazy=true"** configuration, since **roles** field are initialized while we are accessing it first time. 

If we don't access it, it will not be set. 



In addition, we can define **User** entity with compilable pure Java code as follows:

 

~~~~~ java 

public class User {



    ...

    

    @RowMapperObjectField(

        provideViaImplementationProvider = 

            @RowMapperImplementationProvider(

                provideCode = "RoleDAO.getUserRoleListAsStaticMethod(${id})", 

                usedClasses = {RoleDAO.class}), 

        lazy = true)

    private List roles = new ArrayList();

    

    ...

    

} 

~~~~~



Also, we can user our custom data provider classes these implement **"RowMapperObjectFieldDataProvider"** interface with its **"public Object provideData(T ownerObj)"** method. Here is sample usage:



~~~~~ java   

public class User {



    ...

    

    @RowMapperObjectField(

        provideViaCustomProvider = 

            @RowMapperCustomProvider(

                dataProvider = MyCustomDataProvider.class), 

        lazy = true)

    private List roles = new ArrayList();

    

    ...

    

} 

~~~~~



You can find all demo codes (including these samples above) at [https://github.com/serkan-ozal/spring-jdbc-roma-demo](https://github.com/serkan-ozal/spring-jdbc-roma-demo)

 

 

 

## **Roadmap**



* SQL based provider will be supported for getting relations with pure SQL queries by specifying datasource as follows:

    

~~~~~ java      

public class User {



    ...



    @RowMapperObjectField(

        provideViaSqlProvider = 

            @RowMapperSqlProvider(

                sql = 

                    "SELECT r.* FROM ROLE r WHERE r.ID IN " +

                    "(" +

                        "SELECT ur.ROLE_ID FROM user_role ur WHERE ur.USER_ID = ${id}" +

                    ") ORDER BY r.name",

                dataSource = "MyDataSource"),

        lazy = true)

    private List roles = new ArrayList();



    ...



}

~~~~~



* Field based formatters will be supported for formating field from raw value by impelenting custom formatter classes from **"RowMapperFieldGeneratorFormatter"** interface and overriding **"public T format(T value)"** method. Here is sample usage:



~~~~~ java 

public class User {



	...



	@RowMapperField(

		columnName = "surname", 

		fieldFormatters = {MyTrimFormatter.class, MyUpperCaseFormatter.class})

    private String surname;



    ...



}

~~~~~