将属性注入静态的final字段

Question

I have the following class that takes processing events:

public abstract class EventExecutor {

    public static final EventExecutor ON_BALANCE_CHANGE_EXECUTOR = new EventExecutor() {

        private BalanceDao balanceDao;

        @Override
        public void executeEvent() {
            BigDecimal balance;
            //getting the balance
            balanceDao.add(balance);
        }

        //GET, SET, others
    };

    public abstract void executeEvent();
}

The thing is processing some events means to save some data into a persistent store. Since I use Spring 4 I need to perform a corresponding dependency injection in order to perform db -operation.

Curretly, I intent to allow client to perform event handlings via invoking methods on static final fields in order to increase code readability.

So, there is a possibility to do that via ContextLoader.getCurrentWebApplicationContext().getBean(String beanName) but it introduces spring dependencies which is not a desirable solution.

Maybe there is some spring feature allowing us to do that? Couldn't you suggest anything about that?

Answer 1

Since you create object by hand you cannot inject beans directly in anonymous class. The possible solution is to create static inner class for ON_BALANCE_CHANGE_EXECUTOR and define bean of this type in your config.

public abstract class EventExecutor {
public static class OnBalanceChangeExecutor extends EventExecutor {

        private BalanceDao balanceDao;

        @Override
        public void executeEvent() {
            BigDecimal balance;
            //getting the balance
            balanceDao.add(balance);
        }

        //GET, SET, others
    }}

After that you can create bean in your context config:

<bean id="onBalanceChangeExecutor" class = "your.package.EventExecutor$OnBalanceChangeExecutor">
<property name="balanceDao" ref="balanceDao"/>
</bean>