/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.nifi.spring;
import java.io.Closeable;
import java.util.Map;
import org.apache.nifi.flowfile.FlowFile;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.PollableChannel;
/**
* Strategy to support type-safe data exchange between NiFi and Spring. It
* exposes send/receive operations with arguments that are independent of both
* frameworks simplifying conversion from {@link Message} to {@link FlowFile}
* and vice versa.
*/
public interface SpringDataExchanger extends Closeable {
/**
* Sends data to Spring
*
* @param payload
* data that will be used as a payload or {@link Message}
* @param headers
* map that will be used to construct {@link MessageHeaders}
* @param timeout
* value to pass to the
* {@link MessageChannel#send(Message, long)} operation.
* @return 'true' if message was sent and 'false'otherwise.
*/
<T> boolean send(T payload, Map<String, ?> headers, long timeout);
/**
* Receives data from Spring
*
* @param timeout
* value to pass to {@link PollableChannel#receive(long)}
* operation
* @return {@link SpringResponse} representing <i>content</i> (key) and
* <i>attributes</i> of the FlowFile to be constructed.
*/
<T> SpringResponse<T> receive(long timeout);
public static class SpringResponse<T> {
private final T payload;
private final Map<String, Object> headers;
public SpringResponse(T payload, Map<String, Object> headers) {
this.payload = payload;
this.headers = headers;
}
public T getPayload() {
return payload;
}
public Map<String, Object> getHeaders() {
return headers;
}
}
}