@Override
	protected boolean supports(Class<?> clazz) {
		return supportsType(clazz, supportedTargetTypes());
	}
Subclasses implement this to specify supported payload types

@return an array of supported classes or null if any target type is supported
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/integration/bus/converter/AbstractFromMessageConverter.java