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;
  
  /**
   * To support paging of query results, specifies an offset/start instance and limits
   * the number of instances to be retrieved.
   *
   * <p>
   *     Used by {@link NamedQuery#withRange(QueryRange)} and
   *     {@link AllInstancesQuery#withRange(QueryRange)}.
   * </p>
   *
   * @since 2.0 {@index}
   */
  public interface QueryRange extends Serializable {
  
      // -- INTERFACE
  
      /**
       * Whether this range is unconstrained, meaning that there is
       * {@link #hasOffset() no offset} and {@link #hasLimit() no limit} has
       * been specified.
       */
      boolean isUnconstrained();
  
      /**
       * Whether this range has had a non-zero offset specified using
       * {@link #withStart(long)}.
       */
      boolean hasOffset();
  
      /**
       * Whether this range has a limit to the number of instances to be returned
       * using {@link #withLimit(long)}.
       */
      boolean hasLimit();
  
      /**
       * The start index into the set table.
       * (non-negative)
       */
      long getStart();
  
      /**
       * The maximum number of items to return, starting at {@link #getStart()}
       * (non-negative).
       */
      long getLimit();
  
      /**
       * The end index into the set table. Overflow is ignored.
       * (non-negative)
       */
      long getEnd();
  
      // -- TO INT
  
      /**
       * The start index into the set table (as java int primitive)
       * @throws ArithmeticException - if {@code start} overflows an int
       */
      default int getStartAsInt() {
          return Math.toIntExact(getStart());
      }
  
      /**
       * The maximum number of items to return (as java int primitive)
       * if {@code limit} overflows an int, {@link Integer#MAX_VALUE} is returned.
       */
      default int getLimitAsInt() {
          final long limit = getLimit();
          return limit<=((long)Integer.MAX_VALUE)
                  ? Math.toIntExact(limit)
                  : Integer.MAX_VALUE;
      }
  
      /**
       * The end index into the set table. Overflow is ignored. (as java int primitive)
       * if {@code end} overflows an int, {@link Integer#MAX_VALUE} is returned.
       */
      default int getEndAsInt() {
          final long end = getEnd();
          return end<=((long)Integer.MAX_VALUE)
                  ? Math.toIntExact(end)
                  : Integer.MAX_VALUE;
      }
  
      // -- FACTORIES
  
      static QueryRange unconstrained() {
          return of(0L, 0L);
      }
  
      static QueryRange start(long start) {
          return of(start, 0L);
      }
  
      static QueryRange limit(long limit) {
          return of(0L, limit);
      }
  
      static QueryRange of(long... range) {
          return range==null 
              ? new QueryRangeRecord(0L, 0L)
              : new QueryRangeRecord(
                range.length > 0 ? range[0] : 0L,
                range.length > 1 ? range[1] : 0L);
      }
  
      // -- WITHERS
  
      default QueryRange withStart(long start) {
          return of(start, getLimit());
      }
  
      default QueryRange withLimit(long limit) {
          return of(getStart(), limit);
      }
  
  }
  