content: /*
   *  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 org.apache.causeway.applib.query;
  
  import java.io.Serializable;
  import java.util.function.Predicate;
  
  import org.apache.causeway.applib.services.repository.RepositoryService;
  
  import org.jspecify.annotations.NonNull;
  
  /**
   * For use by repository implementations, representing the values of a query.
   *
   * <p>
   * The implementations of these objects are be provided by the underlying
   * persistor/object store; consult its documentation.
   * <p>
   * Implementations are expected to implement the {@link #getRange()}
   * method, which is used to support range / paging
   * the data. Returned result sets are expected to start from index "start",
   * and no more than "count" items are expected.
   * <p>
   * <b>Note:</b> not every object store will necessarily support this
   * interface. In particular, the in-memory object store does not. For this, you
   * can use the {@link Predicate} interface to similar effect, for example in
   * {@link RepositoryService#allMatches(Class, Predicate, long, long)}).
   *
   * <b>Note:</b> that the predicate is applied within the {@link RepositoryService}
   * (ie client-side) rather than being pushed back to the object store.
   *
   * @since 1.x {@index}
   */
  public interface Query<T> extends Serializable {
  
      /**
       * The {@link Class} of the objects returned by this query.
       */
      Class<T> getResultType();
  
      /**
       * A human-readable representation of this query and its values.
       */
      String getDescription();
  
      /**
       * Returns a model with start index into the set table and maximal number of items to return.
       */
      QueryRange getRange();
  
      // -- WITHERS
  
      Query<T> withRange(@NonNull QueryRange range);
  
      default Query<T> withRange(long ...range) {
          return withRange(QueryRange.of(range));
      }
  
      default Query<T> withStart(long start) {
          return withRange(start);
      }
  
      default Query<T> withLimit(long limit) {
          return withRange(0L, limit);
      }
  
      // -- FACTORIES
  
      static <T> Query<T> allInstances(
              final @NonNull Class<T> resultType) {
          return new AllInstancesQueryRecord<>(resultType, QueryRange.unconstrained());
      }
  
      static <T> NamedQuery<T> named(
              final @NonNull Class<T> resultType,
              final @NonNull String queryName) {
          return new NamedQueryRecord<>(resultType, queryName, QueryRange.unconstrained(), null);
      }
  
  }
  