CODEWITHSUNDEEP
javaspring
Anju
Anju

Reputation: 641

How to handle object list by using placeholder in Spring

I have an object namely, Counter

public class Counter{
    private String counterGroup;
    private String counterName;
    private String counterValue;

    //getters & setters
}

public class Task{
    private String taskName;
    private List<Counter> counters;

    //getters & setters
}

In my spring.xml

<context:property-placeholder location="classpath:/test.properties"/>
<bean id="task" class="com.test.Task">
        <property name="taskName" value="${task.name}"/>
        <property name="counters">
        <list>
            <ref bean="counter1"/>
            <ref bean="counter2"/>
        </list>

</bean>

<bean id="counter1" class="com.test.Counter">
      <property name="counterGroup" value=${counter.group1}/>
      <property name="counterName" value=${counter.name1}/>
      <property name="counterValue" value=${counter.value1}/>
</bean>

<bean id="counter2" class="com.test.Counter">
      <property name="counterGroup" value=${counter.group2}/>
      <property name="counterName" value=${counter.name2}/>
      <property name="counterValue" value=${counter.value2}/>
</bean>

In the test.properties

task.name=task1
counter.group1=g1
counter.name1=n1
counter.value1=v1
counter.group2=g2
counter.name2=n2
counter.value2=v2

If I have more number of counters then I have to edit both the properties as well as the spring.xml file. As I'm new to Spring and Java, I don't believe this is the right approach to solve this issue.

Can anybody suggest a different approach to solve the same issue.

Upvotes: 1

Views: 841

Answers (1)

Maks
Maks

Reputation: 202

Well, that is probably approach to use. However you may make your application looks better, if you use factory methods and object builders. For example:

public class Counter {
    .......
    public static Counter createFor(String descriptor){
        String[] params = descriptor.split(":");
        return new Counter(params[0], params[1], params[2]);
    } 
}

your context:

<bean id="task" class="com.test.Task">
        <property name="taskName" value="${task.name}"/>
        <property name="counters">
        <list>
            <bean class="com.test.Counter" factoryMethod="createFor">
                 <constructor-arg ref="${counter.descriptor1}"/>
            </bean>
            <bean class="com.test.Counter" factoryMethod="createFor">
                 <constructor-arg ref="${counter.descriptor2}"/>
            </bean>
        </list>
</bean>

In the test.properties

task.name=task1
counter.descriptor1=g1:n1:v1
counter.descriptor2=g2:n2:v2

Of course you're not limited by this and may upgrade or apply any similar design techniques.

Upvotes: 1

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