public boolean supportsTargetMimeType(MimeType mimeType) {
		for (MimeType targetMimeType : targetMimeTypes) {
			if (mimeType.getType().equals(targetMimeType.getType()) && mimeType.getSubtype().equals(
					targetMimeType.getSubtype())) {
				return true;
			}
		}
		return false;
	}
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