Configurable bean initialization order [SPR-3948]

[spring-projects-issues]

Bernard Macours opened SPR-3948 and commented

There should be a way to order bean initialization. Using "depends-on" is too verbose and is forcing us to explicitly bind business beans with technical beans:

<bean name="my-technical-bean"/>
<bean name="my-business-bean-1" depends-on="my-technical-bean"/>
<bean name="my-business-bean-2" depends-on="my-technical-bean"/>

It would be better to have something like:

<bean name="my-technical-bean" init-order="0"/>
<bean name="my-business-bean-1"/>
<bean name="my-business-bean-2"/>

Of course, we could configure several beans with a different initialization order. For example:
<bean name="my-technical-bean-a" init-order="0"/>
<bean name="my-technical-bean-b" init-order="1"/>

Note: "init-order" would be meaningless for lazy-initialized beans.

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Affects: 2.0.6

4 votes, 5 watchers

[spring-projects-issues]

Larry Chu commented

I think it could be useful to have a way to declare initialization priority without explicitly forcing initialization order, for example we could give a hint to the container than I want X bean initialized as early as possible. This would result in X's dependencies to be initialized, then X would be initialized after the initialization of its dependencies are satisfied.

The form of this hint could be in a "init-order" attribute on each bean declaration or something similar.

I think this could particularly be useful in the cases where we don't have explicit control over the bean declaration, for example with custom namespaces. Often times we don't have the ability to declare dependencies from beans created by a custom namespace element.

See http://forum.springframework.org/showthread.php?p=183445

[spring-projects-issues]

Chris Beams commented

See Phased and SmartLifecycle support introduced in Spring 3.0.

[spring-projects-issues]

Benoit Lacelle commented

Using BeanPostProcessor is another way to provide some ordering in your beans. Check AbstractApplicationContext.refresh() to see how it is enforced.

[spring-projects-issues]

Zoltan Farkas commented

Phased and SmartLifeCycle are considered only during the context start, they are useless during the bean instantiation phase.
Some way of specifying a priority during the init phase would be welcome...