webindex/modules/data/src/main/java/webindex/data/fluo/PageLoader.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 webindex.data.fluo;

import java.net.MalformedURLException;
import java.util.Objects;

import com.google.common.base.Preconditions;
import com.google.gson.Gson;
import org.apache.fluo.api.client.Loader;
import org.apache.fluo.api.client.TransactionBase;
import org.apache.fluo.recipes.core.data.RowHasher;
import org.apache.fluo.recipes.core.types.TypedTransactionBase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import webindex.core.Constants;
import webindex.core.models.Page;
import webindex.core.models.URL;

public class PageLoader implements Loader {

  private static final Logger log = LoggerFactory.getLogger(PageLoader.class);
  private Action action;
  private Page page;
  private URL delUrl;

  private PageLoader() {}

  public static PageLoader updatePage(Page page) {
    Preconditions.checkArgument(!page.isEmpty(), "Page cannot be empty");
    PageLoader update = new PageLoader();
    update.action = Action.UPDATE;
    update.page = page;
    return update;
  }

  public static PageLoader deletePage(URL url) throws MalformedURLException {
    Objects.requireNonNull(url, "Url cannot be null");
    PageLoader update = new PageLoader();
    update.action = Action.DELETE;
    update.delUrl = url;
    return update;
  }

  @Override
  public void load(TransactionBase tx, Context context) throws Exception {

    TypedTransactionBase ttx = Constants.TYPEL.wrap(tx);

    Gson gson = new Gson();
    RowHasher rowHasher = PageObserver.getPageRowHasher();

    switch (action) {
      case DELETE:
        ttx.mutate().row(rowHasher.addHash(delUrl.toUri())).col(Constants.PAGE_NEW_COL)
            .set(Page.DELETE_JSON);
        break;
      case UPDATE:
        String newJson = gson.toJson(page);
        ttx.mutate().row(rowHasher.addHash(page.getUri())).col(Constants.PAGE_NEW_COL).set(newJson);
        break;
      default:
        log.error("PageUpdate called with no action");
    }
  }

  private enum Action {
    UPDATE, DELETE,
  }
}