TransformerProducer.java

/**
 * Copyright (c) Codice Foundation
 * <p/>
 * This is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or any later version.
 * <p/>
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details. A copy of the GNU Lesser General Public License
 * is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 */
package ddf.camel.component.catalog.transformer;

import java.io.IOException;

import javax.activation.MimeTypeParseException;

import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.impl.DefaultProducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import ddf.camel.component.catalog.CatalogComponent;
import ddf.camel.component.catalog.CatalogEndpoint;
import ddf.catalog.transform.CatalogTransformerException;
import ddf.mime.MimeTypeToTransformerMapper;

/**
 * Producer for the custom Camel CatalogComponent. This {@link org.apache.camel.Producer} would map
 * to a Camel <to> route node with a URI like <code>catalog:inputtransformer</code>
 *
 * @author Hugh Rodgers, Lockheed Martin
 * @author William Miller, Lockheed Martin
 * @author ddf.isgs@lmco.com
 *
 */
public abstract class TransformerProducer extends DefaultProducer {
    private static final transient Logger LOGGER = LoggerFactory
            .getLogger(TransformerProducer.class);

    private CatalogEndpoint endpoint;

    /**
     * Constructs the {@link Producer} for the custom Camel CatalogComponent. This producer would
     * map to a Camel <to> route node with a URI like <code>catalog:inputtransformer</code>
     *
     * @param endpoint
     *            the Camel endpoint that created this consumer
     */
    public TransformerProducer(CatalogEndpoint endpoint) {
        super(endpoint);
        this.endpoint = endpoint;

        LOGGER.debug("\"INSIDE InputTransformerProducer constructor for {}",
                endpoint.getTransformerId());
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.camel.Processor#process(org.apache.camel.Exchange)
     */
    public void process(Exchange exchange)
            throws CatalogTransformerException, MimeTypeParseException, IOException {

        LOGGER.debug("ENTERING: process");

        LOGGER.debug("exchange pattern = {}", exchange.getPattern());

        Message in = exchange.getIn();
        Object metacard = null;

        // Get the MIME Type and ID of the transformer to use to transform the
        // request's payload from the endpoint that manages this producer

        String transformerId = in.getHeader(CatalogComponent.ID_PARAMETER, String.class);

        String mimeType = in.getHeader(CatalogComponent.MIME_TYPE_PARAMETER, String.class);

        if (transformerId != null) {
            LOGGER.debug("transformerId retrieved from message header");
            in.removeHeader(CatalogComponent.ID_PARAMETER);
        } else {
            LOGGER.debug("transformerId retrieved from CamelCatalogEndpoint");
            transformerId = endpoint.getTransformerId();
        }

        LOGGER.debug("transformerId = {}", transformerId);

        if (mimeType != null) {
            in.removeHeader(CatalogComponent.MIME_TYPE_PARAMETER);
        } else {
            LOGGER.debug("MIME Type retrieved from CamelCatalogEndpoint");
            mimeType = endpoint.getMimeType();
        }

        LOGGER.debug("MIME Type = {}", mimeType);

        MimeTypeToTransformerMapper mapper = endpoint.getComponent()
                .getMimeTypeToTransformerMapper();

        if (mapper != null) {
            LOGGER.debug("Got a MimeTypeToTransformerMapper service");

            metacard = transform(in, metacard, mimeType, transformerId, mapper);
        } else {
            LOGGER.debug("Did not find a MimeTypeToTransformerMapper service");
            throw new CatalogTransformerException(
                    "Did not find a MimeTypeToTransformerMapper service");
        }

        // Set the response output to the Metacard from the transformation
        exchange.getOut().setBody(metacard);

        LOGGER.debug("EXITING: process");
    }

    protected abstract Object transform(Message in, Object metacard, String mimeType,
            String transformerId, MimeTypeToTransformerMapper mapper)
            throws MimeTypeParseException, IOException, CatalogTransformerException;

}