/*
* Copyright (c) 2009, 2010, 2011, B3log Team
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.b3log.solo.repository.impl;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.b3log.latke.Keys;
import org.b3log.latke.repository.FilterOperator;
import org.b3log.latke.repository.Query;
import org.b3log.latke.repository.RepositoryException;
import org.b3log.latke.repository.SortDirection;
import org.b3log.latke.repository.gae.AbstractGAERepository;
import org.b3log.solo.model.Link;
import org.b3log.solo.repository.LinkRepository;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
/**
* Link Google App Engine repository.
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.0.3, Jan 12, 2011
*/
public final class LinkGAERepository extends AbstractGAERepository
implements LinkRepository {
/**
* Logger.
*/
private static final Logger LOGGER =
Logger.getLogger(LinkGAERepository.class.getName());
@Override
public String getName() {
return Link.LINK;
}
@Override
public JSONObject getByAddress(final String address) {
final Query query = new Query();
query.addFilter(Link.LINK_ADDRESS, FilterOperator.EQUAL, address);
try {
final JSONObject result = get(query);
final JSONArray array = result.getJSONArray(Keys.RESULTS);
if (0 == array.length()) {
return null;
}
return array.getJSONObject(0);
} catch (final Exception e) {
LOGGER.log(Level.SEVERE, e.getMessage(), e);
return null;
}
}
@Override
public int getMaxOrder() throws RepositoryException {
final Query query = new Query();
query.addSort(Link.LINK_ORDER, SortDirection.DESCENDING);
final JSONObject result = get(query);
final JSONArray array = result.optJSONArray(Keys.RESULTS);
if (0 == array.length()) {
return -1;
}
try {
return array.getJSONObject(0).getInt(Link.LINK_ORDER);
} catch (final JSONException e) {
LOGGER.log(Level.SEVERE, e.getMessage(), e);
throw new RepositoryException(e);
}
}
@Override
public JSONObject getByOrder(final int order) {
final Query query = new Query();
query.addFilter(Link.LINK_ORDER, FilterOperator.EQUAL, order);
try {
final JSONObject result = get(query);
final JSONArray array = result.getJSONArray(Keys.RESULTS);
if (0 == array.length()) {
return null;
}
return array.getJSONObject(0);
} catch (final Exception e) {
LOGGER.log(Level.SEVERE, e.getMessage(), e);
return null;
}
}
/**
* Gets the {@link LinkGAERepository} singleton.
*
* @return the singleton
*/
public static LinkGAERepository getInstance() {
return SingletonHolder.SINGLETON;
}
/**
* Private default constructor.
*/
private LinkGAERepository() {
}
/**
* Singleton holder.
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.0.0, Jan 12, 2011
*/
private static final class SingletonHolder {
/**
* Singleton.
*/
private static final LinkGAERepository SINGLETON =
new LinkGAERepository();
/**
* Private default constructor.
*/
private SingletonHolder() {
}
}
}