1 /* 2 * Copyright (C) 2008 The Guava Authors 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 17 package com.google.common.base; 18 19 import static com.google.common.base.Functions.toStringFunction; 20 21 import com.google.common.annotations.GwtCompatible; 22 import com.google.common.collect.ImmutableList; 23 import com.google.common.collect.Lists; 24 import com.google.common.primitives.Longs; 25 import com.google.common.testing.EqualsTester; 26 import com.google.common.testing.SerializableTester; 27 import java.util.Iterator; 28 import java.util.List; 29 import junit.framework.TestCase; 30 31 /** Unit tests for {@link Converter}. */ 32 @GwtCompatible 33 public class ConverterTest extends TestCase { 34 35 private static final Converter<String, Long> STR_TO_LONG = 36 new Converter<String, Long>() { 37 @Override 38 protected Long doForward(String object) { 39 return Long.valueOf(object); 40 } 41 42 @Override 43 protected String doBackward(Long object) { 44 return String.valueOf(object); 45 } 46 47 @Override 48 public String toString() { 49 return "string2long"; 50 } 51 }; 52 53 private static final Long LONG_VAL = 12345L; 54 private static final String STR_VAL = "12345"; 55 56 private static final ImmutableList<String> STRINGS = ImmutableList.of("123", "456"); 57 private static final ImmutableList<Long> LONGS = ImmutableList.of(123L, 456L); 58 testConverter()59 public void testConverter() { 60 assertEquals(LONG_VAL, STR_TO_LONG.convert(STR_VAL)); 61 assertEquals(STR_VAL, STR_TO_LONG.reverse().convert(LONG_VAL)); 62 63 Iterable<Long> convertedValues = STR_TO_LONG.convertAll(STRINGS); 64 assertEquals(LONGS, ImmutableList.copyOf(convertedValues)); 65 } 66 testConvertAllIsView()67 public void testConvertAllIsView() { 68 List<String> mutableList = Lists.newArrayList("789", "123"); 69 Iterable<Long> convertedValues = STR_TO_LONG.convertAll(mutableList); 70 assertEquals(ImmutableList.of(789L, 123L), ImmutableList.copyOf(convertedValues)); 71 72 Iterator<Long> iterator = convertedValues.iterator(); 73 iterator.next(); 74 iterator.remove(); 75 assertEquals(ImmutableList.of("123"), mutableList); 76 } 77 testReverse()78 public void testReverse() { 79 Converter<Long, String> reverseConverter = STR_TO_LONG.reverse(); 80 81 assertEquals(STR_VAL, reverseConverter.convert(LONG_VAL)); 82 assertEquals(LONG_VAL, reverseConverter.reverse().convert(STR_VAL)); 83 84 Iterable<String> convertedValues = reverseConverter.convertAll(LONGS); 85 assertEquals(STRINGS, ImmutableList.copyOf(convertedValues)); 86 87 assertSame(STR_TO_LONG, reverseConverter.reverse()); 88 89 assertEquals("string2long.reverse()", reverseConverter.toString()); 90 91 new EqualsTester() 92 .addEqualityGroup(STR_TO_LONG, STR_TO_LONG.reverse().reverse()) 93 .addEqualityGroup(STR_TO_LONG.reverse(), STR_TO_LONG.reverse()) 94 .testEquals(); 95 } 96 testReverseReverse()97 public void testReverseReverse() { 98 Converter<String, Long> converter = STR_TO_LONG; 99 assertEquals(converter, converter.reverse().reverse()); 100 } 101 testApply()102 public void testApply() { 103 assertEquals(LONG_VAL, STR_TO_LONG.apply(STR_VAL)); 104 } 105 106 private static class StringWrapper { 107 private final String value; 108 StringWrapper(String value)109 public StringWrapper(String value) { 110 this.value = value; 111 } 112 } 113 testAndThen()114 public void testAndThen() { 115 Converter<StringWrapper, String> first = 116 new Converter<StringWrapper, String>() { 117 @Override 118 protected String doForward(StringWrapper object) { 119 return object.value; 120 } 121 122 @Override 123 protected StringWrapper doBackward(String object) { 124 return new StringWrapper(object); 125 } 126 127 @Override 128 public String toString() { 129 return "StringWrapper"; 130 } 131 }; 132 133 Converter<StringWrapper, Long> converter = first.andThen(STR_TO_LONG); 134 135 assertEquals(LONG_VAL, converter.convert(new StringWrapper(STR_VAL))); 136 assertEquals(STR_VAL, converter.reverse().convert(LONG_VAL).value); 137 138 assertEquals("StringWrapper.andThen(string2long)", converter.toString()); 139 140 assertEquals(first.andThen(STR_TO_LONG), first.andThen(STR_TO_LONG)); 141 } 142 testIdentityConverter()143 public void testIdentityConverter() { 144 Converter<String, String> stringIdentityConverter = Converter.identity(); 145 146 assertSame(stringIdentityConverter, stringIdentityConverter.reverse()); 147 assertSame(STR_TO_LONG, stringIdentityConverter.andThen(STR_TO_LONG)); 148 149 assertSame(STR_VAL, stringIdentityConverter.convert(STR_VAL)); 150 assertSame(STR_VAL, stringIdentityConverter.reverse().convert(STR_VAL)); 151 152 assertEquals("Converter.identity()", stringIdentityConverter.toString()); 153 154 assertSame(Converter.identity(), Converter.identity()); 155 } 156 testFrom()157 public void testFrom() { 158 Function<String, Integer> forward = 159 new Function<String, Integer>() { 160 @Override 161 public Integer apply(String input) { 162 return Integer.parseInt(input); 163 } 164 }; 165 Function<Object, String> backward = toStringFunction(); 166 167 Converter<String, Number> converter = Converter.<String, Number>from(forward, backward); 168 169 assertNull(converter.convert(null)); 170 assertNull(converter.reverse().convert(null)); 171 172 assertEquals((Integer) 5, converter.convert("5")); 173 assertEquals("5", converter.reverse().convert(5)); 174 } 175 testNullIsPassedThrough()176 public void testNullIsPassedThrough() { 177 Converter<String, String> nullsArePassed = sillyConverter(false); 178 assertEquals("forward", nullsArePassed.convert("foo")); 179 assertEquals("forward", nullsArePassed.convert(null)); 180 assertEquals("backward", nullsArePassed.reverse().convert("foo")); 181 assertEquals("backward", nullsArePassed.reverse().convert(null)); 182 } 183 testNullIsNotPassedThrough()184 public void testNullIsNotPassedThrough() { 185 Converter<String, String> nullsAreHandled = sillyConverter(true); 186 assertEquals("forward", nullsAreHandled.convert("foo")); 187 assertEquals(null, nullsAreHandled.convert(null)); 188 assertEquals("backward", nullsAreHandled.reverse().convert("foo")); 189 assertEquals(null, nullsAreHandled.reverse().convert(null)); 190 } 191 sillyConverter(final boolean handleNullAutomatically)192 private static Converter<String, String> sillyConverter(final boolean handleNullAutomatically) { 193 return new Converter<String, String>(handleNullAutomatically) { 194 @Override 195 protected String doForward(String string) { 196 return "forward"; 197 } 198 199 @Override 200 protected String doBackward(String string) { 201 return "backward"; 202 } 203 }; 204 } 205 206 public void testSerialization_identity() { 207 Converter<String, String> identityConverter = Converter.identity(); 208 SerializableTester.reserializeAndAssert(identityConverter); 209 } 210 211 public void testSerialization_reverse() { 212 Converter<Long, String> reverseConverter = Longs.stringConverter().reverse(); 213 SerializableTester.reserializeAndAssert(reverseConverter); 214 } 215 216 public void testSerialization_andThen() { 217 Converter<String, Long> converterA = Longs.stringConverter(); 218 Converter<Long, String> reverseConverter = Longs.stringConverter().reverse(); 219 Converter<String, String> composedConverter = converterA.andThen(reverseConverter); 220 SerializableTester.reserializeAndAssert(composedConverter); 221 } 222 223 public void testSerialization_from() { 224 Converter<String, String> dumb = Converter.from(toStringFunction(), toStringFunction()); 225 SerializableTester.reserializeAndAssert(dumb); 226 } 227 } 228