Move back inner classes

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/AbstractParamDescriptor.java

@@ -18,6 +18,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.function.Function;
 
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.Element;
@@ -26,6 +27,7 @@
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeMirror;
+import javax.lang.model.util.TypeKindVisitor8;
 import javax.tools.Diagnostic.Kind;
 
 /**
@@ -104,4 +106,110 @@ private Object coerceValue(TypeMirror type, String value) {
 		return (coercedValue != null) ? coercedValue : value;
 	}
 
+	private static final class DefaultPrimitiveTypeVisitor extends TypeKindVisitor8<Object, Void> {
+
+		static final DefaultPrimitiveTypeVisitor INSTANCE = new DefaultPrimitiveTypeVisitor();
+
+		@Override
+		public Object visitPrimitiveAsBoolean(PrimitiveType t, Void ignore) {
+			return false;
+		}
+
+		@Override
+		public Object visitPrimitiveAsByte(PrimitiveType t, Void ignore) {
+			return (byte) 0;
+		}
+
+		@Override
+		public Object visitPrimitiveAsShort(PrimitiveType t, Void ignore) {
+			return (short) 0;
+		}
+
+		@Override
+		public Object visitPrimitiveAsInt(PrimitiveType t, Void ignore) {
+			return 0;
+		}
+
+		@Override
+		public Object visitPrimitiveAsLong(PrimitiveType t, Void ignore) {
+			return 0L;
+		}
+
+		@Override
+		public Object visitPrimitiveAsChar(PrimitiveType t, Void ignore) {
+			return null;
+		}
+
+		@Override
+		public Object visitPrimitiveAsFloat(PrimitiveType t, Void ignore) {
+			return 0F;
+		}
+
+		@Override
+		public Object visitPrimitiveAsDouble(PrimitiveType t, Void ignore) {
+			return 0D;
+		}
+
+	}
+
+	private static class DefaultValueCoercionTypeVisitor extends TypeKindVisitor8<Object, String> {
+
+		static final DefaultValueCoercionTypeVisitor INSTANCE = new DefaultValueCoercionTypeVisitor();
+
+		private <T extends Number> T parseNumber(String value, Function<String, T> parser,
+				PrimitiveType primitiveType) {
+			try {
+				return parser.apply(value);
+			}
+			catch (NumberFormatException ex) {
+				throw new IllegalArgumentException(
+						String.format("Invalid %s representation '%s'", primitiveType, value));
+			}
+		}
+
+		@Override
+		public Object visitPrimitiveAsBoolean(PrimitiveType t, String value) {
+			return Boolean.parseBoolean(value);
+		}
+
+		@Override
+		public Object visitPrimitiveAsByte(PrimitiveType t, String value) {
+			return parseNumber(value, Byte::parseByte, t);
+		}
+
+		@Override
+		public Object visitPrimitiveAsShort(PrimitiveType t, String value) {
+			return parseNumber(value, Short::parseShort, t);
+		}
+
+		@Override
+		public Object visitPrimitiveAsInt(PrimitiveType t, String value) {
+			return parseNumber(value, Integer::parseInt, t);
+		}
+
+		@Override
+		public Object visitPrimitiveAsLong(PrimitiveType t, String value) {
+			return parseNumber(value, Long::parseLong, t);
+		}
+
+		@Override
+		public Object visitPrimitiveAsChar(PrimitiveType t, String value) {
+			if (value.length() > 1) {
+				throw new IllegalArgumentException(String.format("Invalid character representation '%s'", value));
+			}
+			return value;
+		}
+
+		@Override
+		public Object visitPrimitiveAsFloat(PrimitiveType t, String value) {
+			return parseNumber(value, Float::parseFloat, t);
+		}
+
+		@Override
+		public Object visitPrimitiveAsDouble(PrimitiveType t, String value) {
+			return parseNumber(value, Double::parseDouble, t);
+		}
+
+	}
+
 }