src/main/java/io/mifos/core/cassandra/core/TenantAwareCassandraMapperProvider.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 io.mifos.core.cassandra.core;

import com.datastax.driver.core.Session;
import com.datastax.driver.mapping.Mapper;
import com.datastax.driver.mapping.MappingManager;
import io.mifos.core.lang.TenantContextHolder;
import org.slf4j.Logger;
import org.springframework.core.env.Environment;
import org.springframework.util.Assert;

import javax.annotation.Nonnull;
import java.util.concurrent.ConcurrentHashMap;

public class TenantAwareCassandraMapperProvider {

  private final Environment env;
  private final Logger logger;
  private final CassandraSessionProvider cassandraSessionProvider;
  private final ConcurrentHashMap<String, MappingManager> managerCache;

  public TenantAwareCassandraMapperProvider(@Nonnull final Environment env, @Nonnull final Logger logger,
                                            @Nonnull final CassandraSessionProvider cassandraSessionProvider) {
    super();
    Assert.notNull(env, "An environment must be given.");
    Assert.notNull(logger, "A logger must be given.");
    Assert.notNull(cassandraSessionProvider, "A Cassandra session provider must be given.");
    this.env = env;
    this.logger = logger;
    this.cassandraSessionProvider = cassandraSessionProvider;
    this.managerCache = new ConcurrentHashMap<>();
  }

  @SuppressWarnings("WeakerAccess")
  @Nonnull
  public <T> Mapper<T> getMapper(@Nonnull final Class<T> type) {
    Assert.notNull(type, "A type must be given.");
    if (TenantContextHolder.identifier().isPresent()) {
      final String identifier = TenantContextHolder.checkedGetIdentifier();
      return this.getMapper(identifier, type);
    } else {
      throw new IllegalArgumentException("Could not find tenant identifier, make sure you set an identifier using TenantContextHolder.");
    }
  }

  @SuppressWarnings("WeakerAccess")
  @Nonnull
  public <T> Mapper<T> getMapper(@Nonnull final String identifier, @Nonnull final Class<T> type) {
    Assert.notNull(identifier, "A tenant identifier must be given.");
    Assert.hasText(identifier, "A tenant identifier must be given.");
    Assert.notNull(type, "A type must be given.");

    this.managerCache.computeIfAbsent(identifier, (key) -> {
      this.logger.info("Create new mapping mapper for tenant [" + identifier + "] and type [" + type.getSimpleName() + "].");
      final Session session = this.cassandraSessionProvider.getTenantSession(identifier);

      final MappingManager mappingManager = new MappingManager(session);

      final Mapper<T> typedMapper = mappingManager.mapper(type);
      typedMapper.setDefaultDeleteOptions(OptionProvider.deleteConsistencyLevel(this.env));
      typedMapper.setDefaultGetOptions(OptionProvider.readConsistencyLevel(this.env));
      typedMapper.setDefaultSaveOptions(OptionProvider.writeConsistencyLevel(this.env));

      return mappingManager;
    });

    return this.managerCache.get(identifier).mapper(type);
  }
}