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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      https://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  
18  package org.apache.commons.text.translate;
19  
20  /**
21   * Translates code points to their Unicode escaped value suitable for Java source.
22   *
23   * @since 1.0
24   */
25  public class JavaUnicodeEscaper extends UnicodeEscaper {
26  
27      /**
28       * Constructs a {@code JavaUnicodeEscaper} above the specified value (exclusive).
29       *
30       * @param codePoint above which to escape.
31       * @return The newly created {@code UnicodeEscaper} instance.
32       */
33      public static JavaUnicodeEscaper above(final int codePoint) {
34          return outsideOf(0, codePoint);
35      }
36  
37      /**
38       * Constructs a {@code JavaUnicodeEscaper} below the specified value (exclusive).
39       *
40       * @param codePoint below which to escape.
41       * @return The newly created {@code UnicodeEscaper} instance.
42       */
43      public static JavaUnicodeEscaper below(final int codePoint) {
44          return outsideOf(codePoint, Integer.MAX_VALUE);
45      }
46  
47      /**
48       * Constructs a {@code JavaUnicodeEscaper} between the specified values (inclusive).
49       *
50       * @param codePointLow  above which to escape.
51       * @param codePointHigh below which to escape.
52       * @return The newly created {@code UnicodeEscaper} instance.
53       */
54      public static JavaUnicodeEscaper between(final int codePointLow, final int codePointHigh) {
55          return new JavaUnicodeEscaper(codePointLow, codePointHigh, true);
56      }
57  
58      /**
59       * Constructs a {@code JavaUnicodeEscaper} outside of the specified values (exclusive).
60       *
61       * @param codePointLow  below which to escape.
62       * @param codePointHigh above which to escape.
63       * @return The newly created {@code UnicodeEscaper} instance.
64       */
65      public static JavaUnicodeEscaper outsideOf(final int codePointLow, final int codePointHigh) {
66          return new JavaUnicodeEscaper(codePointLow, codePointHigh, false);
67      }
68  
69      /**
70       * Constructs a {@code JavaUnicodeEscaper} for the specified range. This is the underlying method for the other constructors/builders. The {@code below} and
71       * {@code above} boundaries are inclusive when {@code between} is {@code true} and exclusive when it is {@code false}.
72       *
73       * @param below   int value representing the lowest code point boundary.
74       * @param above   int value representing the highest code point boundary.
75       * @param between whether to escape between the boundaries or outside them.
76       */
77      public JavaUnicodeEscaper(final int below, final int above, final boolean between) {
78          super(below, above, between);
79      }
80  
81      /**
82       * Converts the given code point to a hexadecimal string of the form {@code "\\uXXXX\\uXXXX"}.
83       *
84       * @param codePoint a Unicode code point.
85       * @return The hexadecimal string for the given code point.
86       */
87      @Override
88      protected String toUtf16Escape(final int codePoint) {
89          final char[] surrogatePair = Character.toChars(codePoint);
90          return "\\u" + hex(surrogatePair[0]) + "\\u" + hex(surrogatePair[1]);
91      }
92  }