org.immutables.criteria.repository.sync.SyncFetcherDelegate Maven / Gradle / Ivy

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/*
 * Copyright 2019 Immutables Authors and Contributors
 *
 * 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.immutables.criteria.repository.sync;

import com.google.common.base.Preconditions;
import org.immutables.criteria.backend.Backend;
import org.immutables.criteria.expression.Query;
import org.immutables.criteria.repository.Publishers;
import org.immutables.criteria.repository.reactive.ReactiveFetcher;

import java.util.List;
import java.util.Objects;
import java.util.Optional;

class SyncFetcherDelegate implements SyncFetcher {

  private final ReactiveFetcher fetcher;

  private SyncFetcherDelegate(ReactiveFetcher fetcher) {
    this.fetcher = Objects.requireNonNull(fetcher, "fetcher");
  }

  @Override
  public List fetch() {
    return Publishers.blockingListGet(fetcher.fetch());
  }

  @Override
  public T one() {
    return Publishers.blockingGet(fetcher.one());
  }

  @Override
  public Optional oneOrNone() {
    List list = Publishers.blockingListGet(fetcher.oneOrNone());
    Preconditions.checkState(list.size() <= 1, "Invalid list size: %d", list.size());
    return list.isEmpty() ? Optional.empty() : Optional.of(list.get(0));
  }

  @Override
  public boolean exists() {
    return Publishers.blockingGet(fetcher.exists());
  }

  static  SyncFetcherDelegate fromReactive(ReactiveFetcher fetcher) {
    return new SyncFetcherDelegate(fetcher);
  }

  static  SyncFetcherDelegate of(Query query, Backend.Session session) {
    return fromReactive(ReactiveFetcher.of(query, session));
  }

}