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1 /*
2  * Copyright (C) 2015 Square, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.squareup.javapoet;
17 
18 import java.util.ArrayList;
19 import java.util.Arrays;
20 import java.util.Collection;
21 import java.util.Collections;
22 import java.util.LinkedHashMap;
23 import java.util.LinkedHashSet;
24 import java.util.List;
25 import java.util.Map;
26 import java.util.Set;
27 import javax.lang.model.element.Modifier;
28 
29 import static java.lang.Character.isISOControl;
30 
31 /**
32  * Like Guava, but worse and standalone. This makes it easier to mix JavaPoet with libraries that
33  * bring their own version of Guava.
34  */
35 final class Util {
Util()36   private Util() {
37   }
38 
immutableMultimap(Map<K, List<V>> multimap)39   static <K, V> Map<K, List<V>> immutableMultimap(Map<K, List<V>> multimap) {
40     LinkedHashMap<K, List<V>> result = new LinkedHashMap<>();
41     for (Map.Entry<K, List<V>> entry : multimap.entrySet()) {
42       if (entry.getValue().isEmpty()) continue;
43       result.put(entry.getKey(), immutableList(entry.getValue()));
44     }
45     return Collections.unmodifiableMap(result);
46   }
47 
immutableMap(Map<K, V> map)48   static <K, V> Map<K, V> immutableMap(Map<K, V> map) {
49     return Collections.unmodifiableMap(new LinkedHashMap<>(map));
50   }
51 
checkArgument(boolean condition, String format, Object... args)52   static void checkArgument(boolean condition, String format, Object... args) {
53     if (!condition) throw new IllegalArgumentException(String.format(format, args));
54   }
55 
checkNotNull(T reference, String format, Object... args)56   static <T> T checkNotNull(T reference, String format, Object... args) {
57     if (reference == null) throw new NullPointerException(String.format(format, args));
58     return reference;
59   }
60 
checkState(boolean condition, String format, Object... args)61   static void checkState(boolean condition, String format, Object... args) {
62     if (!condition) throw new IllegalStateException(String.format(format, args));
63   }
64 
immutableList(Collection<T> collection)65   static <T> List<T> immutableList(Collection<T> collection) {
66     return Collections.unmodifiableList(new ArrayList<>(collection));
67   }
68 
immutableSet(Collection<T> set)69   static <T> Set<T> immutableSet(Collection<T> set) {
70     return Collections.unmodifiableSet(new LinkedHashSet<>(set));
71   }
72 
union(Set<T> a, Set<T> b)73   static <T> Set<T> union(Set<T> a, Set<T> b) {
74     Set<T> result = new LinkedHashSet<>();
75     result.addAll(a);
76     result.addAll(b);
77     return result;
78   }
79 
requireExactlyOneOf(Set<Modifier> modifiers, Modifier... mutuallyExclusive)80   static void requireExactlyOneOf(Set<Modifier> modifiers, Modifier... mutuallyExclusive) {
81     int count = 0;
82     for (Modifier modifier : mutuallyExclusive) {
83       if (modifiers.contains(modifier)) count++;
84     }
85     checkArgument(count == 1, "modifiers %s must contain one of %s",
86         modifiers, Arrays.toString(mutuallyExclusive));
87   }
88 
characterLiteralWithoutSingleQuotes(char c)89   static String characterLiteralWithoutSingleQuotes(char c) {
90     // see https://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6
91     switch (c) {
92       case '\b': return "\\b"; /* \u0008: backspace (BS) */
93       case '\t': return "\\t"; /* \u0009: horizontal tab (HT) */
94       case '\n': return "\\n"; /* \u000a: linefeed (LF) */
95       case '\f': return "\\f"; /* \u000c: form feed (FF) */
96       case '\r': return "\\r"; /* \u000d: carriage return (CR) */
97       case '\"': return "\"";  /* \u0022: double quote (") */
98       case '\'': return "\\'"; /* \u0027: single quote (') */
99       case '\\': return "\\\\";  /* \u005c: backslash (\) */
100       default:
101         return isISOControl(c) ? String.format("\\u%04x", (int) c) : Character.toString(c);
102     }
103   }
104 
105   /** Returns the string literal representing {@code value}, including wrapping double quotes. */
stringLiteralWithDoubleQuotes(String value, String indent)106   static String stringLiteralWithDoubleQuotes(String value, String indent) {
107     StringBuilder result = new StringBuilder(value.length() + 2);
108     result.append('"');
109     for (int i = 0; i < value.length(); i++) {
110       char c = value.charAt(i);
111       // trivial case: single quote must not be escaped
112       if (c == '\'') {
113         result.append("'");
114         continue;
115       }
116       // trivial case: double quotes must be escaped
117       if (c == '\"') {
118         result.append("\\\"");
119         continue;
120       }
121       // default case: just let character literal do its work
122       result.append(characterLiteralWithoutSingleQuotes(c));
123       // need to append indent after linefeed?
124       if (c == '\n' && i + 1 < value.length()) {
125         result.append("\"\n").append(indent).append(indent).append("+ \"");
126       }
127     }
128     result.append('"');
129     return result.toString();
130   }
131 }
132