1 /*
2 * Copyright (c) 2002-2024, City of Paris
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright notice
10 * and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright notice
13 * and the following disclaimer in the documentation and/or other materials
14 * provided with the distribution.
15 *
16 * 3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 *
32 * License 1.0
33 */
34 package fr.paris.lutece.plugins.identitystore.utils;
35
36 import java.util.AbstractList;
37 import java.util.ArrayList;
38 import java.util.List;
39
40 public final class Batch<T> extends AbstractList<List<T>>
41 {
42 private final List<T> innerList;
43 private final int partitionSize;
44
45 public Batch( final List<T> innerList, final int partitionSize )
46 {
47 this.innerList = new ArrayList<>( innerList );
48 this.partitionSize = partitionSize;
49 }
50
51 public static <T> Batch<T> ofSize( final List<T> list, final int partitionSize )
52 {
53 return new Batch<>( list, partitionSize );
54 }
55
56 @Override
57 public List<T> get( final int index )
58 {
59 int start = index * this.partitionSize;
60 int end = Math.min( start + this.partitionSize, this.innerList.size( ) );
61
62 if ( start > end )
63 {
64 throw new IndexOutOfBoundsException( "Index " + index + " is out of the list range <0," + ( size( ) - 1 ) + ">" );
65 }
66
67 return new ArrayList<>( this.innerList.subList( start, end ) );
68 }
69
70 @Override
71 public int size( )
72 {
73 return partitionSize == 0 ? 0 : (int) Math.ceil( (double) this.innerList.size( ) / (double) this.partitionSize );
74 }
75
76 public int totalSize( )
77 {
78 return this.innerList.size( );
79 }
80 }