components/camel-avro/src/main/java/org/apache/camel/component/avro/AvroProducer.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.avro;

import org.apache.avro.ipc.Callback;
import org.apache.avro.ipc.Requestor;
import org.apache.avro.ipc.Transceiver;
import org.apache.camel.AsyncCallback;
import org.apache.camel.Endpoint;
import org.apache.camel.Exchange;
import org.apache.camel.support.DefaultAsyncProducer;
import org.apache.commons.lang3.StringUtils;

public abstract class AvroProducer extends DefaultAsyncProducer {

    Transceiver transceiver;
    Requestor requestor;

    public AvroProducer(Endpoint endpoint) {
        super(endpoint);
    }

    @Override
    public boolean isSingleton() {
        return false;
    }

    public abstract Transceiver createTransceiver() throws Exception;

    @Override
    public boolean process(final Exchange exchange, final AsyncCallback callback) {
        Object request = exchange.getIn().getBody();

        try {
            String messageName;
            if (!StringUtils.isEmpty(exchange.getIn().getHeader(AvroConstants.AVRO_MESSAGE_NAME, String.class))) {
                messageName = exchange.getIn().getHeader(AvroConstants.AVRO_MESSAGE_NAME, String.class);
            } else {
                messageName = getEndpoint().getConfiguration().getMessageName();
            }

            requestor.request(messageName, wrapObjectToArray(request), new Callback<Object>() {
                @Override
                public void handleResult(Object result) {
                    // got result from avro, so set it on the exchange and invoke the callback
                    try {
                        // propagate headers
                        exchange.getOut().setHeaders(exchange.getIn().getHeaders());
                        exchange.getOut().setBody(result);
                    } finally {
                        callback.done(false);
                    }
                }

                @Override
                public void handleError(Throwable error) {
                    // got error from avro, so set it on the exchange and invoke the callback
                    try {
                        exchange.setException(error);
                    } finally {
                        callback.done(false);
                    }
                }
            });
        } catch (Exception e) {
            exchange.setException(e);
            callback.done(true);
            return true;
        }

        // okay we continue routing asynchronously
        return false;
    }

    public Object[] wrapObjectToArray(Object object) {
        if (object instanceof Object[]) {
            return (Object[]) object;
        } else {
            Object[] wrapper = new Object[1];
            wrapper[0] = object;
            return wrapper;
        }
    }

    @Override
    protected void doStart() throws Exception {
        super.doStart();
        transceiver = createTransceiver();
        AvroConfiguration configuration = getEndpoint().getConfiguration();
        if (configuration.isReflectionProtocol()) {
            requestor = new AvroReflectRequestor(configuration.getProtocol(), transceiver);
        } else {
            requestor = new AvroSpecificRequestor(configuration.getProtocol(), transceiver);
        }
    }

    @Override
    protected void doStop() throws Exception {
        if (transceiver != null) {
            transceiver.close();
            transceiver = null;
        }
        requestor = null;
        super.doStop();
    }

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