Spring Ioc Types

Spring Ioc Types

Spring Ioc Types

Generally we have two types of IOC styles.

               1.Dependency lookup

               2.Dependency  injection

1.Dependency Lookup:

With dependency lookup your component is responsible to get the dependency component.

Dependency lookup

We have two types of lookup dependency mechanisms they are:

1.1. Dependency pull (DP).

1.2. Contextualized Dependency Lookup (CDL)

1.1. Dependency Pull:

In Dependency pull component will get the other dependent from a centralized registry like JNDI.

1.2 Contextualized Dependency Lookup:

Contextualized dependency lookup is similar to dependency pull, but objects will be taken from container instead of taking from centralized registry

2. Dependency Injection:

With dependency injection spring IOC container automatically injects the dependencies into the components.

Dependency Injection

 We can implement the dependency IOC in three ways.

            1. Constructor-Injection

            2. Setter-Injection

            3. Getter-Injection

1. Constructor-Injection:

In this spring container injects the dependencies through constructor.

public class B

{

        --------

        --------

        --------

}

public class C

{

        --------

        --------

        --------

}

public class A

{

        private C cobj;

        private B bobj;

        public A(C cobj, B bobj)

        {

               this.bobj=bobj;

               this.cobj=cobj;

        }

}

context.xml

<beans>
<bean id="cobj" class="com.javayom.C"/>
<bean id="bobj" class="com.javayom.B"/>
<bean id="aobj" class="com.javayom.A">
<constructor-arg index="1">
<ref bean="bobj" />
</constructor-arg>
<constructor-arg index="0">
<ref bean="cobj" />
</constructor-arg>
</bean>
</beans>

1. Setter-Injection:

In this bean dependencies will be injected into the component through java bean style setter method.

public class B

{

        --------

        --------

        --------

}

public class C

{

        --------

        --------

        --------

}

public class A

{

        private C cobj;

        private B bobj;

        public void setCobj(C cobj)

        {

               this.cobj=cobj;

        }

        public void setBobj (B bobj)

        {

               this.bobj=bobj;

        }

}

context.xml

<beans>
<bean id="cobj" class="com.javayom.C"/>
<bean id="bobj" class="com.javayom.B"/>
<bean id="aobj" class="com.javayom.A">
<property name="cobj">
<ref bean="cobj"/>
</property>
<property name="bobj">
<ref bean="bobj"/>
</property>
</bean>
</beans>

3. Getter-Injection:

public class B

{

        --------

        --------

        --------

}

public class C

{

        --------

        --------

        --------

}

abstract public class A

{

        abstract public B getBobj ();

}

context.xml

<beans>
<bean id="cobj" class="com.javayom.C"/>
<bean id="bobj" class="com.javayom.B"/>
<bean id="aobj" class="com.javayom.A">
<lookup-method name="getBobj" bean="bobj"/>
</bean>
</beans>