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1   package org.apache.maven.search.request;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  /**
23   * Paging.
24   */
25  public final class Paging
26  {
27      private final int pageSize;
28  
29      private final int pageOffset;
30  
31      /**
32       * Creates paging instance with given page size (must be greater than 0) and page offset (must be non-negative).
33       */
34      public Paging( int pageSize, int pageOffset )
35      {
36          if ( pageSize < 1 )
37          {
38              throw new IllegalArgumentException( "pageSize" );
39          }
40          if ( pageOffset < 0 )
41          {
42              throw new IllegalArgumentException( "pageOffset" );
43          }
44          this.pageSize = pageSize;
45          this.pageOffset = pageOffset;
46      }
47  
48      /**
49       * Creates paging instance with given page size (must be grater than 0) and 0 page offset.
50       */
51      public Paging( int pageSize )
52      {
53          this( pageSize, 0 );
54      }
55  
56      /**
57       * Returns the page size: positive integer, never zero or less.
58       */
59      public int getPageSize()
60      {
61          return pageSize;
62      }
63  
64      /**
65       * Returns the page offset: a zero or a positive integer.
66       */
67      public int getPageOffset()
68      {
69          return pageOffset;
70      }
71  
72      /**
73       * Creates "next page" instance relative to this instance.
74       */
75      public Paging nextPage()
76      {
77          return new Paging( pageSize, pageOffset + 1 );
78      }
79  
80      @Override
81      public String toString()
82      {
83          return getClass().getSimpleName() + "{pageSize=" + pageSize + ", pageOffset=" + pageOffset + "}";
84      }
85  }