1 /**
2 * Copyright (C) 2014-2018 Philip Helger (www.helger.com)
3 * philip[at]helger[dot]com
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package com.helger.schematron.pure.preprocess;
18
19 import javax.annotation.Nullable;
20 import javax.annotation.concurrent.NotThreadSafe;
21
22 import com.helger.commons.collection.impl.CommonsHashSet;
23 import com.helger.commons.collection.impl.ICommonsSet;
24 import com.helger.commons.string.ToStringGenerator;
25
26 /**
27 * Utility lookup cache for all used IDs within a schema.
28 *
29 * @author Philip Helger
30 */
31 @NotThreadSafe
32 final class PreprocessorIDPool
33 {
34 private final ICommonsSet <String> m_aUsedIDs = new CommonsHashSet <> ();
35
36 public PreprocessorIDPool ()
37 {}
38
39 /**
40 * Create a unique ID based on the passed one. If the passed ID is not yet
41 * contained, than a numeric index is appended until the ID is unique.
42 *
43 * @param sID
44 * The source ID. May be <code>null</code>.
45 * @return <code>null</code> if the passed ID is <code>null</code> indicating
46 * that no ID is present. Otherwise a unique ID is returned.
47 */
48 @Nullable
49 public String getUniqueID (@Nullable final String sID)
50 {
51 if (sID == null)
52 return null;
53
54 if (m_aUsedIDs.add (sID))
55 {
56 // Unique ID
57 return sID;
58 }
59
60 // Non-unique ID
61 int nIndex = 0;
62 String sNewID = sID + nIndex;
63 do
64 {
65 if (m_aUsedIDs.add (sNewID))
66 {
67 // Now it's unique
68 return sNewID;
69 }
70 ++nIndex;
71 sNewID = sID + nIndex;
72 } while (true);
73 }
74
75 @Override
76 public String toString ()
77 {
78 return new ToStringGenerator (this).append ("usedIDs", m_aUsedIDs).getToString ();
79 }
80 }