1 /**
2 * Copyright (C) 2014-2015 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 java.util.HashSet;
20 import java.util.Set;
21
22 import javax.annotation.Nullable;
23 import javax.annotation.concurrent.NotThreadSafe;
24
25 import com.helger.commons.string.ToStringGenerator;
26
27 /**
28 * Utility lookup cache for all used IDs within a schema.
29 *
30 * @author Philip Helger
31 */
32 @NotThreadSafe
33 final class PreprocessorIDPool
34 {
35 private final Set <String> m_aUsedIDs = new HashSet <String> ();
36
37 public PreprocessorIDPool ()
38 {}
39
40 /**
41 * Create a unique ID based on the passed one. If the passed ID is not yet
42 * contained, than a numeric index is appended until the ID is unique.
43 *
44 * @param sID
45 * The source ID. May be <code>null</code>.
46 * @return <code>null</code> if the passed ID is <code>null</code> indicating
47 * that no ID is present. Otherwise a unique ID is returned.
48 */
49 @Nullable
50 public String getUniqueID (@Nullable final String sID)
51 {
52 if (sID == null)
53 return null;
54
55 if (m_aUsedIDs.add (sID))
56 {
57 // Unique ID
58 return sID;
59 }
60
61 // Non-unique ID
62 int nIndex = 0;
63 String sNewID = sID + nIndex;
64 do
65 {
66 if (m_aUsedIDs.add (sNewID))
67 {
68 // Now it's unique
69 return sNewID;
70 }
71 ++nIndex;
72 sNewID = sID + nIndex;
73 } while (true);
74 }
75
76 @Override
77 public String toString ()
78 {
79 return new ToStringGenerator (this).append ("usedIDs", m_aUsedIDs).toString ();
80 }
81 }