NamespaceMDS.java

/*
 * Copyright © 2015 Cask Data, Inc.
 *
 * 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 co.cask.cdap.store;

import co.cask.cdap.api.dataset.table.Table;
import co.cask.cdap.data2.dataset2.lib.table.MDSKey;
import co.cask.cdap.data2.dataset2.lib.table.MetadataStoreDataset;
import co.cask.cdap.proto.Id;
import co.cask.cdap.proto.NamespaceMeta;

import java.util.List;
import javax.annotation.Nullable;

/**
 * Dataset for namespace metadata
 */
public class NamespaceMDS extends MetadataStoreDataset {

  private static final String TYPE_NAMESPACE = "namespace";

  public NamespaceMDS(Table table) {
    super(table);
  }

  public void create(NamespaceMeta metadata) {
    write(getNamespaceKey(metadata.getName()), metadata);
  }

  @Nullable
  public NamespaceMeta get(Id.Namespace id) {
    return getFirst(getNamespaceKey(id.getId()), NamespaceMeta.class);
  }

  public void delete(Id.Namespace id) {
    deleteAll(getNamespaceKey(id.getId()));
  }

  public List<NamespaceMeta> list() {
    return list(getNamespaceKey(null), NamespaceMeta.class);
  }

  private MDSKey getNamespaceKey(@Nullable String name) {
    MDSKey.Builder builder = new MDSKey.Builder().add(TYPE_NAMESPACE);
    if (name != null) {
      builder.add(name);
    }
    return builder.build();
  }
}