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/*
* Copyright © 2012 The Feign Authors (feign@commonhaus.dev)
*
* 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
*
* http://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 feign.error;
import static feign.Feign.configKey;
import feign.Response;
import feign.codec.Decoder;
import feign.codec.ErrorDecoder;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
public class AnnotationErrorDecoder implements ErrorDecoder {
private final Map<String, MethodErrorHandler> errorHandlerMap;
private final ErrorDecoder defaultDecoder;
AnnotationErrorDecoder(
Map<String, MethodErrorHandler> errorHandlerMap, ErrorDecoder defaultDecoder) {
this.errorHandlerMap = errorHandlerMap;
this.defaultDecoder = defaultDecoder;
}
@Override
public Exception decode(String methodKey, Response response) {
if (errorHandlerMap.containsKey(methodKey)) {
return errorHandlerMap.get(methodKey).decode(response);
}
return defaultDecoder.decode(methodKey, response);
}
public static AnnotationErrorDecoder.Builder builderFor(Class<?> apiType) {
return new Builder(apiType);
}
public static class Builder {
private final Class<?> apiType;
private ErrorDecoder defaultDecoder = new ErrorDecoder.Default();
private Decoder responseBodyDecoder = new Decoder.Default();
public Builder(Class<?> apiType) {
this.apiType = apiType;
}
public Builder withDefaultDecoder(ErrorDecoder defaultDecoder) {
this.defaultDecoder = defaultDecoder;
return this;
}
public Builder withResponseBodyDecoder(Decoder responseBodyDecoder) {
this.responseBodyDecoder = responseBodyDecoder;
return this;
}
public AnnotationErrorDecoder build() {
Map<String, MethodErrorHandler> errorHandlerMap = generateErrorHandlerMapFromApi(apiType);
return new AnnotationErrorDecoder(errorHandlerMap, defaultDecoder);
}
Map<String, MethodErrorHandler> generateErrorHandlerMapFromApi(Class<?> apiType) {
ExceptionGenerator classLevelDefault =
new ExceptionGenerator.Builder()
.withResponseBodyDecoder(responseBodyDecoder)
.withExceptionType(ErrorHandling.NO_DEFAULT.class)
.build();
Map<Integer, ExceptionGenerator> classLevelStatusCodeDefinitions =
new HashMap<Integer, ExceptionGenerator>();
Optional<ErrorHandling> classLevelErrorHandling =
readErrorHandlingIncludingInherited(apiType);
if (classLevelErrorHandling.isPresent()) {
ErrorHandlingDefinition classErrorHandlingDefinition =
readAnnotation(classLevelErrorHandling.get(), responseBodyDecoder);
classLevelDefault = classErrorHandlingDefinition.defaultThrow;
classLevelStatusCodeDefinitions = classErrorHandlingDefinition.statusCodesMap;
}
Map<String, MethodErrorHandler> methodErrorHandlerMap =
new HashMap<String, MethodErrorHandler>();
for (Method method : apiType.getMethods()) {
ErrorHandling methodLevelAnnotation = getErrorHandlingAnnotation(method);
if (methodLevelAnnotation != null) {
ErrorHandlingDefinition methodErrorHandling =
readAnnotation(methodLevelAnnotation, responseBodyDecoder);
ExceptionGenerator methodDefault = methodErrorHandling.defaultThrow;
if (methodDefault.getExceptionType().equals(ErrorHandling.NO_DEFAULT.class)) {
methodDefault = classLevelDefault;
}
MethodErrorHandler methodErrorHandler =
new MethodErrorHandler(
methodErrorHandling.statusCodesMap,
classLevelStatusCodeDefinitions,
methodDefault);
methodErrorHandlerMap.put(configKey(apiType, method), methodErrorHandler);
}
}
return methodErrorHandlerMap;
}
Optional<ErrorHandling> readErrorHandlingIncludingInherited(Class<?> apiType) {
ErrorHandling apiTypeAnnotation = getErrorHandlingAnnotation(apiType);
if (apiTypeAnnotation != null) {
return Optional.of(apiTypeAnnotation);
}
for (Class<?> parentInterface : apiType.getInterfaces()) {
Optional<ErrorHandling> errorHandling =
readErrorHandlingIncludingInherited(parentInterface);
if (errorHandling.isPresent()) {
return errorHandling;
}
}
// Finally, if there's a superclass that isn't Object check if the superclass has anything
if (!apiType.isInterface() && !apiType.getSuperclass().equals(Object.class)) {
return readErrorHandlingIncludingInherited(apiType.getSuperclass());
}
return Optional.empty();
}
private static ErrorHandling getErrorHandlingAnnotation(AnnotatedElement element) {
ErrorHandling annotation = element.getAnnotation(ErrorHandling.class);
if (annotation == null) {
for (Annotation metaAnnotation : element.getAnnotations()) {
annotation = metaAnnotation.annotationType().getAnnotation(ErrorHandling.class);
if (annotation != null) {
break;
}
}
}
return annotation;
}
static ErrorHandlingDefinition readAnnotation(
ErrorHandling errorHandling, Decoder responseBodyDecoder) {
ExceptionGenerator defaultException =
new ExceptionGenerator.Builder()
.withResponseBodyDecoder(responseBodyDecoder)
.withExceptionType(errorHandling.defaultException())
.build();
Map<Integer, ExceptionGenerator> statusCodesDefinition =
new HashMap<Integer, ExceptionGenerator>();
for (ErrorCodes statusCodeDefinition : errorHandling.codeSpecific()) {
for (int statusCode : statusCodeDefinition.codes()) {
if (statusCodesDefinition.containsKey(statusCode)) {
throw new IllegalStateException(
"Status Code ["
+ statusCode
+ "] "
+ "has already been declared to throw ["
+ statusCodesDefinition.get(statusCode).getExceptionType().getName()
+ "] "
+ "and ["
+ statusCodeDefinition.generate()
+ "] - dupe definition");
}
statusCodesDefinition.put(
statusCode,
new ExceptionGenerator.Builder()
.withResponseBodyDecoder(responseBodyDecoder)
.withExceptionType(statusCodeDefinition.generate())
.build());
}
}
return new ErrorHandlingDefinition(defaultException, statusCodesDefinition);
}
private static class ErrorHandlingDefinition {
private final ExceptionGenerator defaultThrow;
private final Map<Integer, ExceptionGenerator> statusCodesMap;
private ErrorHandlingDefinition(
ExceptionGenerator defaultThrow, Map<Integer, ExceptionGenerator> statusCodesMap) {
this.defaultThrow = defaultThrow;
this.statusCodesMap = statusCodesMap;
}
}
}
}