import org.springframework.stereotype.Component;
import org.springframework.beans.factory.annotation.Autowired;
import com.marklogic.client.query.QueryManager;

/**
 * A base class for services that interact with MarkLogic.
 */
@Component
public abstract class ServiceBase {

    /**
     * Manage MarkLogic interaction via a single database client
     */
    @Autowired
    protected Client client;

    /**
     * Gets a new MarkLogic QueryManager for a derived class
     * @return A QueryManager
     */
    protected QueryManager queryManager() {
        return client.getClient().newQueryManager();
    }


}

import com.marklogic.client.io.ValuesHandle;
import com.marklogic.client.query.QueryManager;
import com.marklogic.client.query.ValuesDefinition;
import com.marklogic.client.query.CountedDistinctValue;


import org.springframework.stereotype.Component;

import uk.co.corbas.slides.model.Keyword;

import java.util.ArrayList;
import java.util.HashSet;


/**
 * KeywordService
 * Interface class to query MarkLogic for keywords
 */
@Component
public class KeywordService extends ServiceBase {

    public HashSet<Keyword> listKeywords() {

        HashSet keywords = new HashSet<Keyword>();

        QueryManager qMgr = client.newQueryManager();
        ValuesDefinition defs = qMgr.newValuesDefinition("keyword-list", "keyword-list");
        ValuesHandle results = qMgr.values(defs, new ValuesHandle());

        for (CountedDistinctValue result: results.getValues()) {
            keywords.add(new Keyword(result.get("xs:string", String.class)));
        }

        return keywords;
    }

}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

/**
 * Class to store IoC wiring for Spring. Currently only handles the
 * database client.
 */
@Component
@ComponentScan
public class Wiring {

    @Autowired
    private Environment env;

    @Bean
    public Client client() {
        Client client = new Client(env);
        return client;
    }

}

import com.marklogic.client.query.QueryManager;
import org.springframework.core.env.Environment;

import com.marklogic.client.DatabaseClient;
import com.marklogic.client.DatabaseClientFactory;

/**
 * A simple wrapper for a connection that enables autowiring of the MarkLogic
 * database client in the service classes
 *
 */
public class Client {

    /**
     * Provided by Spring at startup, for accessing environment-specific variables.
     */
    private Environment env;

    /**
     * Database client to be returned to services
     */
    private DatabaseClient client;

    public Client(Environment env) {
        super();
        this.env = env;
        this.client = initializeDatabaseClient();
    }

    /**
     * Get the client
     * @return client - a DatabaseClient object
     */
    public DatabaseClient getClient() {
        return client;
    }

    /**
     * Constructs a Java Client API database Client
     * and stores the instance for use by all connections
     * @return A DatabaseClient for accessing MarkLogic
     */
    private DatabaseClient initializeDatabaseClient() {

        String host = env.getProperty("marklogic.rest.host");
        Integer port = Integer.parseInt(env.getProperty("marklogic.rest.port"));
        String username = env.getProperty("marklogic.rest.user");
        String password = env.getProperty("marklogic.rest.password");

        DatabaseClientFactory.DigestAuthContext context = new DatabaseClientFactory.DigestAuthContext(username, password);
        DatabaseClient client = DatabaseClientFactory.newClient(host, port, context);

        return client;

    }

    /**
     * Get a new query manager
     * @return queryMgr -  a QueryManager object.
     */
    public QueryManager newQueryManager() { return client.newQueryManager(); }
}

@RequestMapping("/keywords")
public HashSet<Keyword> list() {

    KeywordService kws = new KeywordService();
    return kws.listKeywords();
}