可以通过接收消息来触发输出消息，如以下示例所示：

Groovy DSL。 

def dsl = Contract.make {
	description 'Some Description'
	label 'some_label'
	// input is a message
	input {
		// the message was received from this destination
		messageFrom('input')
		// has the following body
		messageBody([
				bookName: 'foo'
		])
		// and the following headers
		messageHeaders {
			header('sample', 'header')
		}
	}
	outputMessage {
		sentTo('output')
		body([
				bookName: 'foo'
		])
		headers {
			header('BOOK-NAME', 'foo')
		}
	}
}

YAML。 

# Human readable description
description: Some description
# Label by means of which the output message can be triggered
label: some_label
# input is a message
input:
  messageFrom: input
  # has the following body
  messageBody:
    bookName: 'foo'
  # and the following headers
  messageHeaders:
    sample: 'header'
# output message of the contract
outputMessage:
  # destination to which the output message will be sent
  sentTo: output
  # the body of the output message
  body:
    bookName: foo
  # the headers of the output message
  headers:
    BOOK-NAME: foo

在前面的示例中，如果在input目标上收到了适当的消息，则将输出消息发送到output。在消息发布者侧，引擎生成一个测试，将该输入消息发送到定义的目的地。在 使用者方面，您可以将消息发送到输入目标，也可以使用标签（示例中为some_label）来触发消息。