Parse into Properties with default values using Commons Digester

Question

<properties>
   <property name="p1">v1</property>
   <property name="p2">v2</property>
</properties>

I want to parse this into a Properties object with {"p1"="v1", "p2"="v2"}. I was able to do this much using commons digester.

forPattern("properties").createObject()
        .ofType(Properties.class);
forPattern("properties/property")
        .callMethod("put").withParamCount(2)
        .withParamTypes(Object.class, Object.class).then()
        .callParam().fromAttribute("name").ofIndex(0).then()
        .callParam().ofIndex(1);

Additionally I also wanted to pass a defaults Properties object that I have. ie instead of new Properties(), I need to do new Properties(defaults) to create the Properties instance. I am aware of .usingConstructor(Properties.class).then() but did not find a way to pass an existing Properties object as an argument.

I am using v3.3.2. Any help is greatly appreciated

Answer 1

Well I figured out this can be done using the FactoryCreateRule

class PropertiesFactory extends AbstractObjectCreationFactory<Properties> {

    Properties defaultProperties;

    public PropertiesFactory(Properties defaultProperties) {
        super();
        this.defaultProperties = defaultProperties;
    }

    @Override
    public Properties createObject(Attributes attributes) throws Exception {
        return new Properties(defaultProperties);
    }

}

...
...

forPattern("properties").factoryCreate()
        .usingFactory(new PropertiesFactory(defaultProperties));
forPattern("properties/property")
        .callMethod("put").withParamCount(2)
        .withParamTypes(Object.class, Object.class).then()
        .callParam().fromAttribute("name").ofIndex(0).then()
        .callParam().ofIndex(1);