Add Period converter support

Add converter support for `javax.time.Period` including:

	String -> Period
	Number -> Period
	Period -> String

Period to Number conversion is not supported since `Period` has no
ability to deduce the number of calendar days in the period.

See gh-21136

Author: Grubhart

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/fieldvalues/javac/JavaCompilerFieldValuesParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -130,6 +130,19 @@ private static class FieldCollector implements TreeVisitor {
 			DATA_SIZE_SUFFIX = Collections.unmodifiableMap(values);
 		}
 
+		private static final String PERIOD_OF = "Period.of";
+
+		private static final Map<String, String> PERIOD_SUFFIX;
+
+		static {
+			Map<String, String> values = new HashMap<>();
+			values.put("Days", "d");
+			values.put("Weeks", "w");
+			values.put("Months", "m");
+			values.put("Years", "y");
+			PERIOD_SUFFIX = Collections.unmodifiableMap(values);
+		}
+
 		private final Map<String, Object> fieldValues = new HashMap<>();
 
 		private final Map<String, Object> staticFinals = new HashMap<>();
@@ -194,6 +207,10 @@ private Object getFactoryValue(ExpressionTree expression, Object factoryValue) {
 			if (dataSizeValue != null) {
 				return dataSizeValue;
 			}
+			Object periodValue = getFactoryValue(expression, factoryValue, PERIOD_OF, PERIOD_SUFFIX);
+			if (periodValue != null) {
+				return periodValue;
+			}
 			return factoryValue;
 		}
 

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/fieldvalues/AbstractFieldValuesProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -100,6 +100,11 @@ void getFieldValues() throws Exception {
 		assertThat(values.get("dataSizeMegabytes")).isEqualTo("20MB");
 		assertThat(values.get("dataSizeGigabytes")).isEqualTo("30GB");
 		assertThat(values.get("dataSizeTerabytes")).isEqualTo("40TB");
+		assertThat(values.get("periodNone")).isNull();
+		assertThat(values.get("periodDays")).isEqualTo("3d");
+		assertThat(values.get("periodWeeks")).isEqualTo("2w");
+		assertThat(values.get("periodMonths")).isEqualTo("10m");
+		assertThat(values.get("periodYears")).isEqualTo("15y");
 	}
 
 	@SupportedAnnotationTypes({ "org.springframework.boot.configurationsample.ConfigurationProperties" })

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/fieldvalues/FieldValues.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -19,6 +19,7 @@
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
+import java.time.Period;
 
 import org.springframework.boot.configurationsample.ConfigurationProperties;
 import org.springframework.util.MimeType;
@@ -136,4 +137,14 @@ public class FieldValues {
 
 	private DataSize dataSizeTerabytes = DataSize.ofTerabytes(40);
 
+	private Period periodNone;
+
+	private Period periodDays = Period.ofDays(3);
+
+	private Period periodWeeks = Period.ofWeeks(2);
+
+	private Period periodMonths = Period.ofMonths(10);
+
+	private Period periodYears = Period.ofYears(15);
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -110,8 +110,11 @@ public static void configure(FormatterRegistry registry) {
 	public static void addApplicationConverters(ConverterRegistry registry) {
 		addDelimitedStringConverters(registry);
 		registry.addConverter(new StringToDurationConverter());
+		registry.addConverter(new StringToPeriodConverter());
 		registry.addConverter(new DurationToStringConverter());
+		registry.addConverter(new PeriodToStringConverter());
 		registry.addConverter(new NumberToDurationConverter());
+		registry.addConverter(new NumberToPeriodConverter());
 		registry.addConverter(new DurationToNumberConverter());
 		registry.addConverter(new StringToDataSizeConverter());
 		registry.addConverter(new NumberToDataSizeConverter());

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

@@ -0,0 +1,51 @@
+/*
+ * 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 java.time.Period;
+import java.util.Collections;
+import java.util.Set;
+
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.GenericConverter;
+
+/**
+ * {@link Converter} to convert from a {@link Number} to a {@link Period}. Supports
+ * {@link Period#parse(CharSequence)} as well a more readable {@code 10m} form.
+ *
+ * @author Eddú Meléndez
+ * @author Edson Chávez
+ * @see PeriodFormat
+ * @see PeriodUnit
+ */
+final class NumberToPeriodConverter implements GenericConverter {
+
+	private final StringToPeriodConverter delegate = new StringToPeriodConverter();
+
+	@Override
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Number.class, Period.class));
+	}
+
+	@Override
+	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+		return this.delegate.convert((source != null) ? source.toString() : null, TypeDescriptor.valueOf(String.class),
+				targetType);
+	}
+
+}

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

@@ -0,0 +1,45 @@
+/*
+ * 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 java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.time.Period;
+
+/**
+ * Annotation that can be used to indicate the format to use when converting a
+ * {@link Period}.
+ *
+ * @author Eddú Meléndez
+ * @author Edson Chávez
+ * @since 2.3.0
+ */
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface PeriodFormat {
+
+	/**
+	 * The {@link Period} format style.
+	 * @return the period format style.
+	 */
+	PeriodStyle value();
+
+}