QueryResponsePostProcessor.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.catalog.impl;

import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import ddf.action.Action;
import ddf.action.ActionProvider;
import ddf.catalog.data.Metacard;
import ddf.catalog.data.Result;
import ddf.catalog.data.impl.AttributeImpl;
import ddf.catalog.operation.QueryResponse;

/**
 * Class called by the catalog framework after all the results have been received from the different
 * federated sources, before any of the post-query plug-ins are called. The current implementation
 * adds the {@link Metacard#RESOURCE_DOWNLOAD_URL} attribute to all the {@link Metacard} objects
 * contained in the {@link QueryResponse}. The download URL is generated using the
 * {@link ActionProvider} whose ID is "catalog.data.metacard.resource".
 */
public class QueryResponsePostProcessor {
    private static final Logger LOGGER = LoggerFactory.getLogger(QueryResponsePostProcessor.class);

    private ActionProvider resourceActionProvider;

    public QueryResponsePostProcessor(ActionProvider resourceActionProvider) {
        this.resourceActionProvider = resourceActionProvider;
    }

    /**
     * Performs any required post-processing on the {@link QueryResponse} object provided.
     * <p>
     * This implementation converts the resource URIs found in the {@link QueryResponse}
     * {@link Metacard}s using the {@link ActionProvider} injected in the constructor.
     *
     * @param response
     *            {@link QueryResponse} to process. Cannot be <code>null</code>.
     */
    public void processResponse(QueryResponse queryResponse) {

        if (resourceActionProvider == null) {
            LOGGER.debug("No ActionProvider, skipping addition of {} attribute in Metacards",
                    Metacard.RESOURCE_DOWNLOAD_URL);
            return;
        }

        for (Result result : queryResponse.getResults()) {
            final Metacard metacard = result.getMetacard();

            if (metacard.getResourceURI() != null) {
                Action action = resourceActionProvider.getAction(metacard);

                if (action != null) {
                    final URL resourceUrl = action.getUrl();

                    if (resourceUrl != null) {
                        metacard.setAttribute(new AttributeImpl(Metacard.RESOURCE_DOWNLOAD_URL,
                                resourceUrl.toString()));
                    }
                }
            }
        }
    }
}