uk.org.openeyes.oink.facade.FacadeRoutingServiceFactory.java Source code

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Here is the source code for uk.org.openeyes.oink.facade.FacadeRoutingServiceFactory.java

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/*******************************************************************************
 * OINK - Copyright (c) 2014 OpenEyes Foundation
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package uk.org.openeyes.oink.facade;

import java.security.InvalidParameterException;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationConverter;
import org.hl7.fhir.instance.model.ResourceType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import uk.org.openeyes.oink.common.HttpMapper;
import uk.org.openeyes.oink.common.HttpMapperEntry;
import uk.org.openeyes.oink.domain.HttpMethod;
import uk.org.openeyes.oink.rabbit.RabbitRoute;

/**
 * 
 * Builds a {@link FacadeRoutingService} using information in the adapters properties file.
 * 
 * facade.mapping.1.service    (Optional) Used to route to different end-systems
 * facade.mapping.1.resource   (Optional) E.g. Patient, Practitioner or Organization
 * facade.mapping.1.routingKey (Mandatory) The rabbit routing key
 * facade.mapping.1.method      (Optional) GET, POST or PUT etc
 * facade.mapping.2.service
 * facade.mapping.2.resource
 *   ..   ...    ..  ..
 * 
 * @author Oliver Wilkie
 */
public class FacadeRoutingServiceFactory {

    private static final Logger log = LoggerFactory.getLogger(FacadeRoutingServiceFactory.class);

    private static final String MAPPING_KEY = "facade.mapping";
    private static final String MAPPING_DEFAULT_EXCHANGE_KEY = "rabbit.defaultExchange";
    private static final String MAPPING_DEFAULT_REPLY_ROUTING_KEY = "rabbit.responseRoutingKey";

    private Properties adapterProperties;

    public FacadeRoutingServiceFactory(Properties props) {
        this.adapterProperties = props;
    }

    public FacadeRoutingService createInstance() {
        HttpMapper<RabbitRoute> mappings;
        String defaultReplyRoutingKey;

        log.debug("Using props: " + adapterProperties.toString());

        Configuration config = ConfigurationConverter.getConfiguration(adapterProperties);

        String defaultExchange = config.getString(MAPPING_DEFAULT_EXCHANGE_KEY);
        defaultReplyRoutingKey = config.getString(MAPPING_DEFAULT_REPLY_ROUTING_KEY);

        Configuration facadeConfig = config.subset(MAPPING_KEY);

        int numOfMappings = getNumberOfMappingsGiven(facadeConfig);

        List<HttpMapperEntry<RabbitRoute>> entries = new LinkedList<HttpMapperEntry<RabbitRoute>>();
        for (int i = 1; i <= numOfMappings; i++) {
            Configuration mappingCfg = getMappingsDetailsForIndex(i, facadeConfig);

            String service = mappingCfg.getString("service");
            if (service != null && !service.equals("*") && isReservedResourceWord(service)) {
                throw new InvalidParameterException("A service name cannot be a Resource name");
            }

            String resource = mappingCfg.getString("resource");
            if (resource != null && !resource.equals("*") && !isReservedResourceWord(resource)) {
                throw new InvalidParameterException(
                        "A resource must be a recognised Resource name e.g. Patient  (case-sensitive)");
            }

            String method = mappingCfg.getString("method");
            HttpMethod methodEnum;
            if (method != null && !method.equals("*") && !isValidHttpMethod(method)) {
                throw new InvalidParameterException(
                        "A resource must be a recognised method verb e.g. POST,GET,PUT  (case-sensitive)");
            } else if (method == null || method.equals("*")) {
                methodEnum = HttpMethod.ANY;
            } else {
                methodEnum = HttpMethod.valueOf(method);
            }

            String routingKey = mappingCfg.getString("routingKey");
            if (routingKey == null || routingKey.isEmpty()) {
                throw new InvalidParameterException("A routingKey must be given for every mapping entry");
            }

            StringBuilder uri = new StringBuilder();
            if (!(service == null || service.isEmpty())) {
                uri.append(service);
                uri.append("/");
            }

            if (!(resource == null || resource.isEmpty())) {
                uri.append(resource);
            }

            uri.append("*");

            RabbitRoute route = new RabbitRoute(routingKey, defaultExchange);

            HttpMapperEntry<RabbitRoute> entry = new HttpMapperEntry<RabbitRoute>(uri.toString(), methodEnum,
                    route);

            entries.add(entry);

        }

        mappings = new HttpMapper<RabbitRoute>(entries);
        return new FacadeRoutingService(mappings, defaultReplyRoutingKey);
    }

    private int getNumberOfMappingsGiven(Configuration facadeConfig) {
        if (facadeConfig.isEmpty()) {
            log.error("No mapping entries are in the program's config file. The facade will not map any requests!");
            return 0;
        }

        int numOfMappings = 0;

        while (facadeConfig.getKeys(++numOfMappings + ".").hasNext()) {
            numOfMappings++;
        }

        log.info("Found " + numOfMappings + " mapping entries");

        return numOfMappings;
    }

    private Configuration getMappingsDetailsForIndex(int i, Configuration facadeConfig) {
        return facadeConfig.subset(Integer.toString(i));
    }

    private static boolean isReservedResourceWord(String s) {
        try {
            return ResourceType.valueOf(s) != null;
        } catch (IllegalArgumentException ex) {
            return false;
        }
    }

    private static boolean isValidHttpMethod(String m) {
        try {
            return HttpMethod.valueOf(m) != null;
        } catch (IllegalArgumentException ex) {
            return false;
        }
    }

}