BAEL-529

spring-boot/src/main/java/org/baeldung/config/WebConfig.java

@@ -0,0 +1,17 @@
+package org.baeldung.config;
+
+import org.baeldung.web.resolver.HeaderVersionArgumentResolver;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+
+import java.util.List;
+
+@Configuration
+public class WebConfig extends WebMvcConfigurerAdapter {
+
+    @Override
+    public void addArgumentResolvers(final List<HandlerMethodArgumentResolver> argumentResolvers) {
+        argumentResolvers.add(new HeaderVersionArgumentResolver());
+    }
+}

spring-boot/src/main/java/org/baeldung/controller/GenericEntityController.java

@@ -1,11 +1,15 @@
 package org.baeldung.controller;
 
 import org.baeldung.domain.GenericEntity;
+import org.baeldung.web.resolver.Version;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -35,4 +39,16 @@ public class GenericEntityController {
     public GenericEntity findById(@PathVariable Long id) {
         return entityList.stream().filter(entity -> entity.getId().equals(id)).findFirst().get();
     }
+
+    @RequestMapping("/entity/findbydate/{date}")
+    public GenericEntity findByDate(@PathVariable("date") LocalDateTime date) {
+        return entityList.stream().findFirst().get();
+    }
+
+    @RequestMapping("/entity/findbyversion")
+    public ResponseEntity findByVersion(@Version String version) {
+        return version != null
+            ? new ResponseEntity(entityList.stream().findFirst().get(), HttpStatus.OK)
+            : new ResponseEntity(HttpStatus.NOT_FOUND);
+    }
 }

spring-boot/src/main/java/org/baeldung/converter/StringToEnumConverterFactory.java

@@ -0,0 +1,27 @@
+package org.baeldung.converter;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.ConverterFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class StringToEnumConverterFactory implements ConverterFactory<String, Enum> {
+
+    private static class StringToEnumConverter<T extends Enum> implements Converter<String, T> {
+
+        private Class<T> enumType;
+
+        public StringToEnumConverter(Class<T> enumType) {
+            this.enumType = enumType;
+        }
+
+        public T convert(String source) {
+            return (T) Enum.valueOf(this.enumType, source.trim());
+        }
+    }
+
+    @Override
+    public <T extends Enum> Converter<String, T> getConverter(final Class<T> targetType) {
+        return new StringToEnumConverter(targetType);
+    }
+}

spring-boot/src/main/java/org/baeldung/converter/StringToLocalDateTimeConverter.java

@@ -0,0 +1,21 @@
+package org.baeldung.converter;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.stereotype.Component;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+
+@Component
+public class StringToLocalDateTimeConverter implements Converter<String, LocalDateTime> {
+
+    @Override
+    public LocalDateTime convert(final String source) {
+        try {
+            return LocalDateTime.parse(source, DateTimeFormatter.ISO_LOCAL_DATE_TIME);
+        } catch (DateTimeParseException e) {
+            throw new IllegalArgumentException("Couldn't parse value");
+        }
+    }
+}

spring-boot/src/main/java/org/baeldung/web/resolver/HeaderVersionArgumentResolver.java

@@ -0,0 +1,26 @@
+package org.baeldung.web.resolver;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.stereotype.Component;
+import org.springframework.web.bind.support.WebDataBinderFactory;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.method.support.ModelAndViewContainer;
+
+import javax.servlet.http.HttpServletRequest;
+
+@Component
+public class HeaderVersionArgumentResolver implements HandlerMethodArgumentResolver {
+
+    @Override
+    public boolean supportsParameter(final MethodParameter methodParameter) {
+        return methodParameter.getParameterAnnotation(Version.class) != null;
+    }
+
+    @Override
+    public Object resolveArgument(final MethodParameter methodParameter, final ModelAndViewContainer modelAndViewContainer, final NativeWebRequest nativeWebRequest, final WebDataBinderFactory webDataBinderFactory) throws Exception {
+        HttpServletRequest request = (HttpServletRequest) nativeWebRequest.getNativeRequest();
+
+        return request.getHeader("Version");
+    }
+}

spring-boot/src/main/java/org/baeldung/web/resolver/Version.java

@@ -0,0 +1,11 @@
+package org.baeldung.web.resolver;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.PARAMETER)
+public @interface Version {
+}