Coverage Summary for Class: ICU4Jv26TextNormalizer (com.acciente.oacc.normalizer.icu4j)

Class	Method, %	Line, %
ICU4Jv26TextNormalizer	100% (6/ 6)	90.9% (20/ 22)
ICU4Jv26TextNormalizer$LazyInitSingletonHolder	100% (2/ 2)	100% (2/ 2)
total	100% (8/ 8)	91.7% (22/ 24)
1 /*
2  * Copyright 2009-2017, Acciente LLC
3  *
4  * Acciente LLC licenses this file to you under the
5  * Apache License, Version 2.0 (the "License"); you
6  * may not use this file except in compliance with the
7  * License. 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
12  * writing, software distributed under the License is
13  * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
14  * OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing
16  * permissions and limitations under the License.
17  */
18 
19 package com.acciente.oacc.normalizer.icu4j;
20 
21 import com.acciente.oacc.normalizer.TextNormalizer;
22 import com.ibm.icu.text.Normalizer;
23 
24 public class ICU4Jv26TextNormalizer extends TextNormalizer {
25    // constants
26    private static final char ZERO_CHAR = '\0';
27 
28    // we use the singleton holder pattern to lazy initialize the singleton instance
29    // in a thread safe manner without the need for any explicit locking
30    // (see https://en.wikipedia.org/wiki/Initialization-on-demand_holder_idiom).
31    private static class LazyInitSingletonHolder {
32       private static final TextNormalizer INSTANCE = new ICU4Jv26TextNormalizer();
33    }
34 
35    private ICU4Jv26TextNormalizer() {
36       // this "no-op" call to the Normalize class is *very* important, without it when the
37       // com.ibm.icu.text.Normalizer class is not present in the classpath a load of the
38       // class will not fail until it is attempted in the normalizeToNfc() method below -- which
39       // is too late. The class load needs to fail here to cause the getInstance() method below to
40       // propagate the class load exception and correctly trigger the fallback to the JDK based
41       // TextNormalizer implementation in the parent class's TextNormalizer#getInstance().
42       Normalizer.normalize("", Normalizer.NFC, 0);
43    }
44 
45    public static TextNormalizer getInstance() {
46       return LazyInitSingletonHolder.INSTANCE;
47    }
48 
49    @Override
50    public char[] normalizeToNfc(char[] source) {
51       int destBufferSize = 3 * source.length;
52       char[] result = null;
53       do {
54          char[] destBuffer = new char[destBufferSize];
55          try {
56             final int destBufferUsedCount = Normalizer.normalize(source, destBuffer, Normalizer.NFC, 0);
57             result = copyContents(destBuffer, destBufferUsedCount);
58          }
59          catch (IndexOutOfBoundsException e) {
60             // NOTE: since we allocate an initial buffer that is 3x of
61             // the source text length we never expect this to happen
62 
63             // try the next loop iteration with a larger buffer
64             destBufferSize += source.length;
65          }
66          finally {
67             // zero out the current dest buffer
68             zeroOut(destBuffer);
69          }
70       } while (result == null);
71 
72       return result;
73    }
74 
75    /**
76     * Returns a copy of the contents of specified char array
77     *
78     * @param source char array to copy from
79     * @param countToCopy the number of characters to copy from the source
80     *
81     * @return a character array with
82     */
83    private char[] copyContents(char[] source, int countToCopy) {
84       final char[] copy = new char[countToCopy];
85       System.arraycopy(source, 0, copy, 0, countToCopy);
86       return copy;
87    }
88 
89    /**
90     * Sets all contents in the specified char array to {@value ZERO_CHAR}.
91     *
92     * @param dest the char array to zero out
93     */
94    private void zeroOut(char[] dest) {
95       for (int i = 0; i < dest.length; i++) {
96          dest[i] = ZERO_CHAR;
97       }
98    }
99 }