1 /*
2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.
8  *
9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 package sampleapi.util;
25 
26 import java.util.StringTokenizer;
27 import java.util.ArrayList;
28 
29 /*
30  * The class implements unknown number of nested loops. The number of modifiers
31  * in class/interface definitions could be any size. Annotations are also multiplied
32  * by this class.
33  * That is, dataset xml can provide any number of modifier sets, and generator should
34  * iterate through all possible modifiers, annotations and types combinations.
35  *
36  * For example, class definition xml provides 3 modifiers sets:
37  *
38  * "public,private"
39  * "static"
40  * "final,abstract"
41  *
42  * and one types set "void,int"
43  *
44  * the class will generate the sequence like:
45  * "public static final void"
46  * "public static final int"
47  * "public static abstract void"
48  * "public static abstract int"
49  * "private static final void"
50  * "private static final int"
51  * "private static abstract void"
52  * "private static abstract int".
53  *
54  * This sequence could be processed by just one loop instead of four.
55  *
56  * In other places where the number of possible positions are known,
57  * the generator uses nested loops instead.
58  */
59 public class SimpleMultiplier {
60 
61     ArrayList<ArrayList<String>> valueSpace = new ArrayList<>();
62 
63     int size = 0;
64     int index = 0;
65 
addAxis(String values)66     public void addAxis(String values) {
67         ArrayList<String> valueAxis = new ArrayList<>();
68         StringTokenizer valuesTokens = new StringTokenizer(values, "|");
69         while (valuesTokens.hasMoreTokens())
70             valueAxis.add(valuesTokens.nextToken());
71         valueSpace.add(valueAxis);
72     }
73 
initIterator()74     public void initIterator() {
75         size = 1;
76         if (!valueSpace.isEmpty()) {
77             for (int i = 0; i < valueSpace.size(); i++)
78                 size *= valueSpace.get(i).size();
79         }
80         index = 0;
81     }
82 
hasNext()83     public boolean hasNext() {
84         return index < size;
85     }
86 
getNext()87     public ArrayList<String> getNext() {
88         ArrayList<String> next = new ArrayList<>();
89         int positionIndex = index;
90 
91         // last added changing faster
92         for (int i = valueSpace.size() - 1; i >= 0; i--) {
93             ArrayList<String> valueAxis = valueSpace.get(i);
94             int axisSize = valueAxis.size();
95             next.add(valueAxis.get(positionIndex % axisSize));
96             positionIndex /= axisSize;
97         }
98         index += 1;
99 
100         return next;
101     }
102 }
103