String to Pattern and String to Regex converters

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/ApplicationConversionService.java

@@ -20,6 +20,7 @@
 import java.util.Set;
 
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.core.KotlinDetector;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.ConverterRegistry;
@@ -120,6 +121,10 @@ public static void addApplicationConverters(ConverterRegistry registry) {
 		registry.addConverter(new NumberToDataSizeConverter());
 		registry.addConverter(new StringToFileConverter());
 		registry.addConverter(new InputStreamSourceToByteArrayConverter());
+		registry.addConverter(new StringToPatternConverter());
+		if (KotlinDetector.isKotlinPresent()) {
+			registry.addConverter(StringToRegexConverter.INSTANCE);
+		}
 		registry.addConverterFactory(new LenientStringToEnumConverterFactory());
 		registry.addConverterFactory(new LenientBooleanToEnumConverterFactory());
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/StringToPatternConverter.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.convert;
+
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.GenericConverter;
+import org.springframework.util.ObjectUtils;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.regex.Pattern;
+
+/**
+ * {@link Converter} to convert from a {@link String} to a {@link Pattern}
+ *
+ * @author Mikhael Sokolov
+ * @see Pattern
+ */
+final class StringToPatternConverter implements GenericConverter {
+
+	@Override
+	public Set<GenericConverter.ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new GenericConverter.ConvertiblePair(String.class, Pattern.class));
+	}
+
+	@Override
+	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+		if (ObjectUtils.isEmpty(source)) return null;
+		return Pattern.compile((String) source, Pattern.MULTILINE);
+	}
+}

spring-boot-project/spring-boot/src/main/kotlin/org/springframework/boot/convert/StringToRegexConverter.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.convert
+
+import org.springframework.core.convert.TypeDescriptor
+import org.springframework.core.convert.converter.Converter
+import org.springframework.core.convert.converter.GenericConverter
+
+/**
+ * [Converter] to convert from a [String] to a [Regex]
+ *
+ * @author Mikhael Sokolov
+ * @see Regex
+ */
+internal object StringToRegexConverter : GenericConverter {
+	override fun getConvertibleTypes(): Set<GenericConverter.ConvertiblePair> = setOf(GenericConverter.ConvertiblePair(String::class.java, Regex::class.java))
+	override fun convert(str: Any?, p1: TypeDescriptor, p2: TypeDescriptor): Any? = (str as? String)?.ifEmpty { return null }?.toRegex(RegexOption.MULTILINE)
+}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/convert/StringToPatternConverterTests.java

@@ -0,0 +1,54 @@
+
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.convert;
+
+import org.junit.jupiter.params.provider.Arguments;
+import org.springframework.core.convert.ConversionService;
+
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link StringToPatternConverter}.
+ *
+ * @author Mikhael Sokolov
+ */
+class StringToPatternConverterTests {
+
+	@ConversionServiceTest
+	void convertWhenStringShouldReturnPattern(ConversionService conversionService) {
+		assertThat(convert(conversionService, "([A-Z])\\w+").pattern()).isEqualTo(Pattern.compile("([A-Z])\\w+", Pattern.MULTILINE).pattern());
+		assertThat(convert(conversionService, "(\\\\W)*(\\\\S)*").pattern()).isEqualTo(Pattern.compile("(\\\\W)*(\\\\S)*", Pattern.MULTILINE).pattern());
+	}
+
+	@ConversionServiceTest
+	void convertWhenEmptyShouldReturnNull(ConversionService conversionService) {
+		assertThat(convert(conversionService, "")).isNull();
+	}
+
+	private Pattern convert(ConversionService conversionService, String source) {
+		return conversionService.convert(source, Pattern.class);
+	}
+
+	@SuppressWarnings("unused")
+	static Stream<? extends Arguments> conversionServices() {
+		return ConversionServiceArguments.with(new StringToPatternConverter());
+	}
+}

spring-boot-project/spring-boot/src/test/kotlin/org/springframework/boot/convert/StringToRegexConverterTests.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.boot.convert
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.params.provider.Arguments
+import org.springframework.core.convert.ConversionService
+import java.util.stream.Stream
+
+/**
+ * Tests for [StringToRegexConverter].
+ *
+ * @author Mikhael Sokolov
+ */
+internal class StringToRegexConverterTests {
+
+	@ConversionServiceTest
+	fun convertWhenStringShouldReturnPattern(conversionService: ConversionService) {
+		assertThat(conversionService.convert("([A-Z])\\w+")?.pattern).isEqualTo(Regex("([A-Z])\\w+", RegexOption.MULTILINE).pattern)
+		assertThat(conversionService.convert("(\\\\W)*(\\\\S)*")?.pattern).isEqualTo(Regex("(\\\\W)*(\\\\S)*", RegexOption.MULTILINE).pattern)
+	}
+
+	@ConversionServiceTest
+	fun convertWhenEmptyShouldReturnNull(conversionService: ConversionService) {
+		assertThat(conversionService.convert("")).isNull()
+	}
+
+	private fun ConversionService.convert(source: String): Regex? = convert(source, Regex::class.java)
+
+	companion object {
+		@JvmStatic
+		fun conversionServices(): Stream<out Arguments?> = ConversionServiceArguments.with(StringToRegexConverter)
+	}
+}