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add HystrixCommand support
fixes OpenFeigngh-189
1 parent 46e8911 commit c17756c

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‎CHANGELOG.md‎

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### Version 8.11
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* Adds support for Hystrix via a `HystrixFeign` builder.
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### Version 8.10
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* Adds HTTP status to FeignException for easier response handling
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* Reads class-level @Produces/@Consumes JAX-RS annotations

‎README.md‎

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```
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### Hystrix
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[HystrixFeign](https://github.com/Netflix/feign/tree/master/hystrix) configures circuit breaker support provided by [Hystrix](https://github.com/Netflix/Hystrix).
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To use Hystrix with Feign, add the Hystrix module to your classpath. Then use the `HystrixFeign` builder:
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```java
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MyService api = HystrixFeign.builder().target(MyService.class, "https://myAppProd");
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```
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### SLF4J
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[SLF4JModule](https://github.com/Netflix/feign/tree/master/slf4j) allows directing Feign's logging to [SLF4J](http://www.slf4j.org/), allowing you to easily use a logging backend of your choice (Logback, Log4J, etc.)
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‎core/src/main/java/feign/MethodMetadata.java‎

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return configKey;
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}
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MethodMetadata configKey(String configKey) {
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public MethodMetadata configKey(String configKey) {
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this.configKey = configKey;
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return this;
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}
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return returnType;
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}
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MethodMetadata returnType(Type returnType) {
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public MethodMetadata returnType(Type returnType) {
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this.returnType = returnType;
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return this;
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}
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return urlIndex;
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}
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MethodMetadata urlIndex(Integer urlIndex) {
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public MethodMetadata urlIndex(Integer urlIndex) {
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this.urlIndex = urlIndex;
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return this;
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}
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return bodyIndex;
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}
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MethodMetadata bodyIndex(Integer bodyIndex) {
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public MethodMetadata bodyIndex(Integer bodyIndex) {
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this.bodyIndex = bodyIndex;
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return this;
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}
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return bodyType;
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}
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MethodMetadata bodyType(Type bodyType) {
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public MethodMetadata bodyType(Type bodyType) {
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this.bodyType = bodyType;
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return this;
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}

‎hystrix/README.md‎

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Hystrix
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===================
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This module wraps Feign's http requests in [Hystrix](https://github.com/Netflix/Hystrix/), which enables the [Circuit Breaker Pattern](https://en.wikipedia.org/wiki/Circuit_breaker_design_pattern).
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To use Hystrix with Feign, add the Hystrix module to your classpath. Then, configure Feign to use the `HystrixInvocationHandler`:
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```java
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GitHub github = HystrixFeign.builder()
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.target(GitHub.class, "https://api.github.com");
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```
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Methods that do *not* return [`HystrixCommand`](https://netflix.github.io/Hystrix/javadoc/com/netflix/hystrix/HystrixCommand.html) are still wrapped in a `HystrixCommand`, but `execute()` is automatically called for you.
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For asynchronous or reactive use, return `HystrixCommand<YourType>` rather than just `YourType`.
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```java
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interface YourApi {
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@RequestLine("GET /yourtype/{id}")
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HystrixCommand<YourType> getYourType(@Param("id") String id);
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@RequestLine("GET /yourtype/{id}")
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YourType getYourTypeSynchronous(@Param("id") String id);
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}
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YourApi api = HystrixFeign.builder()
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.target(YourApi.class, "https://example.com");
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// for reactive
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api.getYourType("a").toObservable();
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// for asynchronous
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api.getYourType("a").queue();
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// for synchronous
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api.getYourType("a").execute();
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// or to apply hystrix to existing feign methods.
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api.getYourTypeSynchronous("a");
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```

‎hystrix/build.gradle‎

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apply plugin: 'java'
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sourceCompatibility = 1.6
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dependencies {
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compile project(':feign-core')
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compile 'com.netflix.hystrix:hystrix-core:1.4.18'
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testCompile 'junit:junit:4.12'
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testCompile 'org.assertj:assertj-core:1.7.1' // last version supporting JDK 7
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testCompile 'com.squareup.okhttp:mockwebserver:2.5.0'
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testCompile project(':feign-gson')
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testCompile project(':feign-core').sourceSets.test.output // for assertions
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}

‎hystrix/src/main/java/feign/hystrix/HystrixDelegatingContract.java‎

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package feign.hystrix;
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import static feign.Util.resolveLastTypeParameter;
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import java.lang.reflect.ParameterizedType;
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import java.lang.reflect.Type;
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import java.util.List;
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import com.netflix.hystrix.HystrixCommand;
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import feign.Contract;
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import feign.MethodMetadata;
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final class HystrixDelegatingContract implements Contract {
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private final Contract delegate;
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public HystrixDelegatingContract(Contract delegate) {
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this.delegate = delegate;
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}
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@Override
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public List<MethodMetadata> parseAndValidatateMetadata(Class<?> targetType) {
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List<MethodMetadata> metadatas = this.delegate.parseAndValidatateMetadata(targetType);
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for (MethodMetadata metadata : metadatas) {
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Type type = metadata.returnType();
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if (type instanceof ParameterizedType && ((ParameterizedType) type).getRawType().equals(HystrixCommand.class)) {
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Type actualType = resolveLastTypeParameter(type, HystrixCommand.class);
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metadata.returnType(actualType);
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}
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}
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return metadatas;
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}
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}

‎hystrix/src/main/java/feign/hystrix/HystrixFeign.java‎

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package feign.hystrix;
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import com.netflix.hystrix.HystrixCommand;
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import feign.Contract;
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import feign.Feign;
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/**
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* Allows Feign interfaces to return HystrixCommand objects.
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* Also decorates normal Feign methods with circuit breakers, but calls {@link HystrixCommand#execute()} directly.
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*/
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public final class HystrixFeign {
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public static Builder builder() {
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return new Builder();
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}
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public static final class Builder extends Feign.Builder {
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public Builder() {
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invocationHandlerFactory(new HystrixInvocationHandler.Factory());
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contract(new HystrixDelegatingContract(new Contract.Default()));
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}
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@Override
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public Feign.Builder contract(Contract contract) {
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return super.contract(new HystrixDelegatingContract(contract));
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}
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}
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}

‎hystrix/src/main/java/feign/hystrix/HystrixInvocationHandler.java‎

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/*
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* Copyright 2015 Netflix, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package feign.hystrix;
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import static feign.Util.checkNotNull;
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import java.lang.reflect.InvocationHandler;
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import java.lang.reflect.Method;
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import java.util.Map;
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import com.netflix.hystrix.HystrixCommand;
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import com.netflix.hystrix.HystrixCommandGroupKey;
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import com.netflix.hystrix.HystrixCommandKey;
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import feign.InvocationHandlerFactory;
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import feign.InvocationHandlerFactory.MethodHandler;
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import feign.Target;
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final class HystrixInvocationHandler implements InvocationHandler {
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private final Target target;
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private final Map<Method, MethodHandler> dispatch;
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HystrixInvocationHandler(Target target, Map<Method, MethodHandler> dispatch) {
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this.target = checkNotNull(target, "target");
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this.dispatch = checkNotNull(dispatch, "dispatch");
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}
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@Override
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public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
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String groupKey = this.target.name();
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String commandKey = method.getName();
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HystrixCommand.Setter setter = HystrixCommand.Setter
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.withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
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.andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
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HystrixCommand<Object> hystrixCommand = new HystrixCommand<Object>(setter) {
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@Override
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protected Object run() throws Exception {
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try {
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return HystrixInvocationHandler.this.dispatch.get(method).invoke(args);
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} catch (Exception e) {
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throw e;
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} catch (Throwable t) {
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throw (Error)t;
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}
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}
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};
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if (HystrixCommand.class.isAssignableFrom(method.getReturnType())) {
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return hystrixCommand;
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}
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return hystrixCommand.execute();
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}
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static final class Factory implements InvocationHandlerFactory {
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@Override
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public InvocationHandler create(Target target, Map<Method, MethodHandler> dispatch) {
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return new HystrixInvocationHandler(target, dispatch);
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}
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}
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}

‎hystrix/src/test/java/feign/hystrix/HystrixBuilderTest.java‎

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package feign.hystrix;
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import static feign.assertj.MockWebServerAssertions.assertThat;
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import java.util.List;
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import org.junit.Rule;
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import org.junit.Test;
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import org.junit.rules.ExpectedException;
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import com.netflix.hystrix.HystrixCommand;
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import com.squareup.okhttp.mockwebserver.MockResponse;
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import com.squareup.okhttp.mockwebserver.MockWebServer;
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import feign.Headers;
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import feign.RequestLine;
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import feign.gson.GsonDecoder;
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public class HystrixBuilderTest {
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@Rule
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public final ExpectedException thrown = ExpectedException.none();
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@Rule
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public final MockWebServer server = new MockWebServer();
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@Test
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public void hystrixCommand() {
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server.enqueue(new MockResponse().setBody("\"foo\""));
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TestInterface api = target();
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HystrixCommand<String> command = api.command();
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assertThat(command).isNotNull();
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assertThat(command.execute()).isEqualTo("foo");
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}
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@Test
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public void hystrixCommandInt() {
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server.enqueue(new MockResponse().setBody("1"));
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TestInterface api = target();
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HystrixCommand<Integer> command = api.intCommand();
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assertThat(command).isNotNull();
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assertThat(command.execute()).isEqualTo(new Integer(1));
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}
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@Test
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public void hystrixCommandList() {
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server.enqueue(new MockResponse().setBody("[\"foo\",\"bar\"]"));
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TestInterface api = target();
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HystrixCommand<List<String>> command = api.listCommand();
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assertThat(command).isNotNull();
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assertThat(command.execute()).hasSize(2).contains("foo", "bar");
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}
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@Test
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public void plainString() {
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server.enqueue(new MockResponse().setBody("\"foo\""));
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TestInterface api = target();
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String string = api.get();
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assertThat(string).isEqualTo("foo");
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}
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@Test
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public void plainList() {
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server.enqueue(new MockResponse().setBody("[\"foo\",\"bar\"]"));
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TestInterface api = target();
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List<String> list = api.getList();
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assertThat(list).isNotNull().hasSize(2).contains("foo", "bar");
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}
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private TestInterface target() {
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return HystrixFeign.builder()
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.decoder(new GsonDecoder())
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.target(TestInterface.class, "http://localhost:" + server.getPort());
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}
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interface TestInterface {
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@RequestLine("GET /")
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@Headers("Accept: application/json")
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HystrixCommand<List<String>> listCommand();
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@RequestLine("GET /")
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@Headers("Accept: application/json")
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HystrixCommand<String> command();
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@RequestLine("GET /")
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@Headers("Accept: application/json")
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HystrixCommand<Integer> intCommand();
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@RequestLine("GET /")
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@Headers("Accept: application/json")
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String get();
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@RequestLine("GET /")
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@Headers("Accept: application/json")
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List<String> getList();
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}
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}

‎settings.gradle‎

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rootProject.name='feign'
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include 'core', 'sax', 'gson', 'httpclient', 'jackson', 'jaxb', 'jaxrs', 'okhttp', 'ribbon', 'slf4j', 'jackson-jaxb'
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include 'core', 'sax', 'gson', 'httpclient', 'jackson', 'jaxb', 'jaxrs', 'okhttp', 'ribbon', 'slf4j', 'jackson-jaxb', 'hystrix'
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rootProject.children.each { childProject ->
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childProject.name = 'feign-' + childProject.name

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