components/camel-spark/src/main/java/org/apache/camel/component/spark/RddSparkProducer.java

/*
 * 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.camel.component.spark;

import java.util.List;

import org.apache.camel.Exchange;
import org.apache.camel.support.DefaultProducer;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaRDDLike;

import static org.apache.camel.component.spark.SparkConstants.SPARK_RDD_CALLBACK_HEADER;
import static org.apache.camel.component.spark.SparkConstants.SPARK_RDD_HEADER;

public class RddSparkProducer extends DefaultProducer {

    public RddSparkProducer(SparkEndpoint endpoint) {
        super(endpoint);
    }

    @Override
    public void process(Exchange exchange) throws Exception {
        JavaRDDLike rdd = resolveRdd(exchange);
        RddCallback rddCallback = resolveRddCallback(exchange);
        Object body = exchange.getIn().getBody();
        Object result = body instanceof List ? rddCallback.onRdd(rdd, ((List) body).toArray(new Object[0])) : rddCallback.onRdd(rdd, body);
        collectResults(exchange, result);
    }

    @Override
    public SparkEndpoint getEndpoint() {
        return (SparkEndpoint) super.getEndpoint();
    }

    // Helpers

    protected void collectResults(Exchange exchange, Object result) {
        if (result instanceof JavaRDD) {
            JavaRDD rddResults = (JavaRDD) result;
            if (getEndpoint().isCollect()) {
                exchange.getIn().setBody(rddResults.collect());
            } else {
                exchange.getIn().setBody(result);
                exchange.getIn().setHeader(SPARK_RDD_HEADER, result);
            }
        } else {
            exchange.getIn().setBody(result);
        }
    }

    protected JavaRDDLike resolveRdd(Exchange exchange) {
        if (exchange.getIn().getHeader(SPARK_RDD_HEADER) != null) {
            return (JavaRDD) exchange.getIn().getHeader(SPARK_RDD_HEADER);
        } else if (getEndpoint().getRdd() != null) {
            return getEndpoint().getRdd();
        } else {
            throw new IllegalStateException("No RDD defined.");
        }
    }

    protected RddCallback resolveRddCallback(Exchange exchange) {
        if (exchange.getIn().getHeader(SPARK_RDD_CALLBACK_HEADER) != null) {
            return  (RddCallback) exchange.getIn().getHeader(SPARK_RDD_CALLBACK_HEADER);
        } else if (getEndpoint().getRddCallback() != null) {
            return getEndpoint().getRddCallback();
        } else {
            throw new IllegalStateException("Cannot resolve RDD callback.");
        }
    }

}