cucumber-jvm: alternative proposal for specifying default xstream converters

ConverterRegistry.java

package features.foo.alternative;

import cucumber.runtime.xstream.converters.ConverterMatcher;

public interface ConverterRegistry {
	Class<? extends ConverterMatcher> getConverter(Class<?> type);
}

FooStepDefs.java

package features.foo.alternative;

import java.util.List;
import java.util.Map;

import junit.framework.Assert;
import cucumber.annotation.en.Given;
import cucumber.runtime.xstream.annotations.XStreamConverter;
import cucumber.runtime.xstream.converters.ConverterMatcher;
import cucumber.runtime.xstream.converters.basic.AbstractSingleValueConverter;
import cucumber.runtime.xstream.converters.extended.ToStringConverter;
import features.foo.alternative.DefaultConvertersAlternative.MyConverters;

@StepDefOptions(defaultConverters = MyConverters.class)
public class FooStepDefs {
	
	// default converters
	static class MyConverters extends MapBasedConverterRegistry {
		public MyConverters(Map<Class<?>, Class<? extends ConverterMatcher>> converterRegistryMap) {
			super(new ConverterMapBuilder()
					.convert(Foo.class).with(FooConverter.class)
					.convert(Bar.class).with(BarConverter.class)
					.convert(Baz.class).with(BazConverter.class)
					.build());
		}
	}

	@Given("^I have some foo named \"([^\"]*)\"$")
	public void I_have_some_foo_named(Foo foo) {
		Assert.assertNotNull(foo.getName());
	}

	@Given("^I have some stuff in a data table:$")
	public void I_have_some_stuff_in_a_data_table(List<StuffInTable> stuffInTable) {
		for (StuffInTable stuff : stuffInTable) {
			Assert.assertNotNull(stuff.foo.getName());
			Assert.assertNotNull(stuff.bar.getName());
			Assert.assertNotNull(stuff.baz.getName());
		}
	}

	public static class StuffInTable {
		public Foo foo;
		// override default converter if necessary
		@XStreamConverter(AlternativeBarConverter.class)
		public Bar bar;
		public Baz baz;
	}
}

MapBasedConverterRegistry.java

package features.foo.alternative;

import java.util.HashMap;
import java.util.Map;

import cucumber.runtime.xstream.converters.ConverterMatcher;

public class MapBasedConverterRegistry implements ConverterRegistry {

	protected static class ConverterMapBuilder {
		private final Map<Class<?>, Class<? extends ConverterMatcher>> map = new HashMap<Class<?>, Class<? extends ConverterMatcher>>();
		private Class<?> type;

		public ConverterMapBuilder convert(Class<?> type) {
			assert type != null;
			assert this.type == null;
			this.type = type;
			return this;
		}

		public ConverterMapBuilder with(
				Class<? extends ConverterMatcher> converter) {
			assert converter != null;
			map.put(type, converter);
			this.type = null;
			return this;
		}

		public HashMap<Class<?>, Class<? extends ConverterMatcher>> build() {
			assert this.type == null;
			return new HashMap<Class<?>, Class<? extends ConverterMatcher>>(map);
		}
	}

	private final Map<Class<?>, Class<? extends ConverterMatcher>> converterRegistryMap;

	public MapBasedConverterRegistry(
			Map<Class<?>, Class<? extends ConverterMatcher>> converterRegistryMap) {
		this.converterRegistryMap = converterRegistryMap;
	}

	public Class<? extends ConverterMatcher> getConverter(Class<?> type) {
		return converterRegistryMap.get(type);
	}
}

StepDefOptions.java

package features.foo.alternative;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE })
public @interface StepDefOptions {
	Class<? extends ConverterRegistry> defaultConverters();
}