MetacardResourceSizePlugin.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.plugin.resourcesize.metacard;

import java.util.List;

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

import ddf.catalog.cache.ResourceCacheInterface;
import ddf.catalog.cache.impl.CacheKey;
import ddf.catalog.data.Attribute;
import ddf.catalog.data.Metacard;
import ddf.catalog.data.Result;
import ddf.catalog.data.impl.AttributeImpl;
import ddf.catalog.operation.QueryResponse;
import ddf.catalog.operation.ResourceRequest;
import ddf.catalog.operation.impl.ResourceRequestById;
import ddf.catalog.plugin.PluginExecutionException;
import ddf.catalog.plugin.PostQueryPlugin;
import ddf.catalog.plugin.StopProcessingException;
import ddf.catalog.resource.data.ReliableResource;

public class MetacardResourceSizePlugin implements PostQueryPlugin {

    private static final Logger LOGGER = LoggerFactory.getLogger(MetacardResourceSizePlugin.class);

    private ResourceCacheInterface cache;

    public MetacardResourceSizePlugin(ResourceCacheInterface cache) {
        this.cache = cache;
    }

    @Override
    public QueryResponse process(QueryResponse input)
            throws PluginExecutionException, StopProcessingException {

        List<Result> results = input.getResults();
        for (Result result : results) {
            Metacard metacard = result.getMetacard();
            if (metacard != null) {
                // Can only search cache based on Metacard - no way to generate ResourceRequest with
                // any properties for use in generating the CacheKey
                final ResourceRequest resourceRequest = new ResourceRequestById(metacard.getId());
                CacheKey cacheKey = new CacheKey(metacard, resourceRequest);
                String key = null;
                ReliableResource cachedResource = null;
                try {
                    key = cacheKey.generateKey();
                    ClassLoader tccl = Thread.currentThread().getContextClassLoader();
                    try {
                        Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
                        cachedResource = (ReliableResource) cache.getValid(key, metacard);
                    } finally {
                        Thread.currentThread().setContextClassLoader(tccl);
                    }
                } catch (Exception e) {
                    LOGGER.debug("Unable to retrieve cached resource for metacard id = {}",
                            metacard.getId());
                }
                if (cachedResource != null) {
                    long resourceSize = cachedResource.getSize();
                    if (resourceSize > 0 && cachedResource.hasProduct()) {
                        LOGGER.debug("Setting resourceSize = {} for metacard ID = {}", resourceSize,
                                metacard.getId());
                        Attribute resourceSizeAttribute = new AttributeImpl(Metacard.RESOURCE_SIZE,
                                String.valueOf(resourceSize));
                        metacard.setAttribute(resourceSizeAttribute);
                    } else {
                        LOGGER.debug("resourceSize <= 0 for metacard ID = {}", metacard.getId());
                    }
                } else {
                    LOGGER.debug("No cached resource for cache key = {}", key);
                }
            }
        }

        return input;
    }

}