refactor: split feign-core into feign-api and feign-core

annotation-error-decoder/src/main/java/feign/error/AnnotationErrorDecoder.java

@@ -19,9 +19,9 @@
 
 import feign.Response;
 import feign.codec.Decoder;
-import feign.codec.DefaultDecoder;
-import feign.codec.DefaultErrorDecoder;
 import feign.codec.ErrorDecoder;
+import feign.core.codec.DefaultDecoder;
+import feign.core.codec.DefaultErrorDecoder;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;
 import java.lang.reflect.Method;

annotation-error-decoder/src/test/java/feign/error/AnnotationErrorDecoderExceptionConstructorsTest.java

@@ -17,7 +17,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import feign.codec.DefaultDecoder;
+import feign.core.codec.DefaultDecoder;
 import feign.error.AnnotationErrorDecoderExceptionConstructorsTest.TestClientInterfaceWithDifferentExceptionConstructors;
 import feign.error.AnnotationErrorDecoderExceptionConstructorsTest.TestClientInterfaceWithDifferentExceptionConstructors.DeclaredDefaultConstructorException;
 import feign.error.AnnotationErrorDecoderExceptionConstructorsTest.TestClientInterfaceWithDifferentExceptionConstructors.DeclaredDefaultConstructorWithOtherConstructorsException;

api/pom.xml

@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>io.github.openfeign</groupId>
+    <artifactId>feign-parent</artifactId>
+    <version>14.0-alpha1-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>feign-api</artifactId>
+  <name>Feign API</name>
+  <description>Feign API</description>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <version>${mockito.version}</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>com.squareup.okhttp3</groupId>
+      <artifactId>mockwebserver</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-context</artifactId>
+      <version>${spring-context.version}</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>com.google.auto.service</groupId>
+      <artifactId>auto-service-annotations</artifactId>
+      <version>${auto-service-annotations.version}</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-jar-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>test-jar</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <annotationProcessorPaths>
+            <path>
+              <groupId>com.google.auto.service</groupId>
+              <artifactId>auto-service</artifactId>
+              <version>${auto-service-annotations.version}</version>
+            </path>
+          </annotationProcessorPaths>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>enforce-banned-dependencies</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <bannedDependencies>
+                  <message>feign-api should never include any dependencies, this is a design choice to keep api light</message>
+                  <excludes>
+                    <exclude>*:*:*:*:*:*</exclude>
+                  </excludes>
+                  <includes>
+                    <include>*:*:*:*:test:*</include>
+                    <include>com.google.auto.service:auto-service-annotations</include>
+                  </includes>
+                </bannedDependencies>
+              </rules>
+              <fail>true</fail>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

core/src/main/java/feign/AsyncClient.java → api/src/main/java/feign/AsyncClient.java

@@ -18,7 +18,6 @@
 import feign.Request.Options;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ExecutorService;
 
 /** Submits HTTP {@link Request requests} asynchronously, with an optional context. */
 @Experimental
@@ -39,17 +38,6 @@ public interface AsyncClient<C> {
    */
   CompletableFuture<Response> execute(Request request, Options options, Optional<C> requestContext);
 
-  /**
-   * @deprecated use {@link DefaultAsyncClient} instead.
-   */
-  @Deprecated
-  class Default<C> extends DefaultAsyncClient<C> {
-
-    public Default(Client client, ExecutorService executorService) {
-      super(client, executorService);
-    }
-  }
-
   /**
    * A synchronous implementation of {@link AsyncClient}
    *

core/src/main/java/feign/AsyncFeign.java → api/src/main/java/feign/AsyncFeign.java

@@ -72,7 +72,7 @@ public static class AsyncBuilder<C> extends BaseBuilder<AsyncBuilder<C>, AsyncFe
     private AsyncContextSupplier<C> defaultContextSupplier = () -> null;
     private AsyncClient<C> client =
         new DefaultAsyncClient<>(
-            new DefaultClient(null, null), LazyInitializedExecutorService.instance);
+            ServiceLoaderUtils.defaults().client(), LazyInitializedExecutorService.instance);
     private MethodInfoResolver methodInfoResolver = MethodInfo::new;
 
     @Deprecated

core/src/main/java/feign/BaseBuilder.java → api/src/main/java/feign/BaseBuilder.java

@@ -18,13 +18,9 @@
 import static feign.ExceptionPropagationPolicy.NONE;
 
 import feign.Feign.ResponseMappingDecoder;
-import feign.Logger.NoOpLogger;
 import feign.Request.Options;
 import feign.codec.Codec;
 import feign.codec.Decoder;
-import feign.codec.DefaultDecoder;
-import feign.codec.DefaultEncoder;
-import feign.codec.DefaultErrorDecoder;
 import feign.codec.Encoder;
 import feign.codec.ErrorDecoder;
 import feign.interceptor.MethodInterceptor;
@@ -46,25 +42,33 @@ public abstract class BaseBuilder<B extends BaseBuilder<B, T>, T> implements Clo
   protected List<ResponseInterceptor> responseInterceptors = new ArrayList<>();
   protected List<MethodInterceptor> methodInterceptors = new ArrayList<>();
   protected Logger.Level logLevel = Logger.Level.NONE;
-  protected Contract contract = new DefaultContract();
-  protected Retryer retryer = new DefaultRetryer();
-  protected Logger logger = new NoOpLogger();
-  protected Encoder encoder = new DefaultEncoder();
-  protected Decoder decoder = new DefaultDecoder();
+  protected Contract contract;
+  protected Retryer retryer;
+  protected Logger logger;
+  protected Encoder encoder;
+  protected Decoder decoder;
   protected boolean closeAfterDecode = true;
   protected boolean decodeVoid = false;
-  protected QueryMapEncoder queryMapEncoder = QueryMap.MapEncoder.FIELD.instance();
-  protected ErrorDecoder errorDecoder = new DefaultErrorDecoder();
+  protected QueryMapEncoder queryMapEncoder;
+  protected ErrorDecoder errorDecoder;
   protected Options options = new Options();
-  protected InvocationHandlerFactory invocationHandlerFactory =
-      new DefaultInvocationHandlerFactory();
+  protected InvocationHandlerFactory invocationHandlerFactory;
   protected boolean dismiss404;
   protected ExceptionPropagationPolicy propagationPolicy = NONE;
   protected List<Capability> capabilities = new ArrayList<>();
 
   public BaseBuilder() {
     super();
     thisB = (B) this;
+    FeignDefaults defaults = ServiceLoaderUtils.defaults();
+    this.contract = defaults.contract();
+    this.retryer = defaults.retryer();
+    this.logger = defaults.logger();
+    this.encoder = defaults.encoder();
+    this.decoder = defaults.decoder();
+    this.queryMapEncoder = defaults.queryMapEncoder();
+    this.errorDecoder = defaults.errorDecoder();
+    this.invocationHandlerFactory = defaults.invocationHandlerFactory();
   }
 
   public B logLevel(Logger.Level logLevel) {

api/src/main/java/feign/Client.java

@@ -0,0 +1,33 @@
+/*
+ * 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;
+
+import feign.Request.Options;
+import java.io.IOException;
+
+/** Submits HTTP {@link Request requests}. Implementations are expected to be thread-safe. */
+public interface Client {
+
+  /**
+   * Executes a request against its {@link Request#url() url} and returns a response.
+   *
+   * @param request safe to replay.
+   * @param options options to apply to this request.
+   * @return connected response, {@link Response.Body} is absent or unread.
+   * @throws IOException on a network error connecting to {@link Request#url()}.
+   */
+  Response execute(Request request, Options options) throws IOException;
+}

core/src/main/java/feign/Contract.java → api/src/main/java/feign/Contract.java

@@ -245,10 +245,4 @@ protected void nameParam(MethodMetadata data, String name, int i) {
       data.indexToName().put(i, names);
     }
   }
-
-  /**
-   * @deprecated use {@link DefaultContract} instead.
-   */
-  @Deprecated
-  class Default extends DefaultContract {}
 }

core/src/main/java/feign/Feign.java → api/src/main/java/feign/Feign.java

@@ -96,7 +96,7 @@ public static String configKey(Method method) {
 
   public static class Builder extends BaseBuilder<Builder, Feign> {
 
-    private Client client = new DefaultClient(null, null);
+    private Client client = ServiceLoaderUtils.defaults().client();
 
     @Override
     public Builder logLevel(Logger.Level logLevel) {

api/src/main/java/feign/FeignDefaults.java

@@ -0,0 +1,51 @@
+/*
+ * 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;
+
+import feign.codec.Decoder;
+import feign.codec.Encoder;
+import feign.codec.ErrorDecoder;
+
+/**
+ * Aggregated factory for Feign's built-in default components. A single implementation is discovered
+ * once through {@link java.util.ServiceLoader}, replacing what would otherwise be a separate lookup
+ * per component. {@code feign-core} supplies the standard implementation; an application may
+ * override the whole set by registering its own provider (any implementation outside the {@code
+ * feign.core} package takes precedence).
+ *
+ * <p>Each accessor returns a fresh instance, mirroring the per-builder defaults Feign created
+ * before the lookups were consolidated.
+ */
+public interface FeignDefaults {
+
+  Contract contract();
+
+  Retryer retryer();
+
+  Logger logger();
+
+  Encoder encoder();
+
+  Decoder decoder();
+
+  QueryMapEncoder queryMapEncoder();
+
+  ErrorDecoder errorDecoder();
+
+  InvocationHandlerFactory invocationHandlerFactory();
+
+  Client client();
+}

core/src/main/java/feign/InvocationHandlerFactory.java → api/src/main/java/feign/InvocationHandlerFactory.java

@@ -36,10 +36,4 @@ interface Factory<C> {
       MethodHandler create(Target<?> target, MethodMetadata md, C requestContext);
     }
   }
-
-  /**
-   * @deprecated use {@link DefaultInvocationHandlerFactory} instead.
-   */
-  @Deprecated
-  static final class Default extends DefaultInvocationHandlerFactory {}
 }

core/src/main/java/feign/QueryMap.java → api/src/main/java/feign/QueryMap.java

@@ -18,8 +18,6 @@
 import static java.lang.annotation.ElementType.PARAMETER;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
-import feign.querymap.BeanQueryMapEncoder;
-import feign.querymap.FieldQueryMapEncoder;
 import java.lang.annotation.Retention;
 import java.util.List;
 import java.util.Map;
@@ -88,11 +86,21 @@
 
   public enum MapEncoder {
     // the latter DEFAULT will use BaseBuilder instance
-    BEAN(new BeanQueryMapEncoder()),
-    FIELD(new FieldQueryMapEncoder()),
-    DEFAULT(null);
+    BEAN("feign.core.querymap.BeanQueryMapEncoder"),
+    FIELD("feign.core.querymap.FieldQueryMapEncoder"),
+    DEFAULT((QueryMapEncoder) null);
 
-    private QueryMapEncoder mapEncoder;
+    private final QueryMapEncoder mapEncoder;
+
+    private MapEncoder(String className) {
+      QueryMapEncoder encoder = null;
+      try {
+        encoder = (QueryMapEncoder) Class.forName(className).getDeclaredConstructor().newInstance();
+      } catch (Exception e) {
+        // ignore
+      }
+      this.mapEncoder = encoder;
+    }
 
     private MapEncoder(QueryMapEncoder mapEncoder) {
       this.mapEncoder = mapEncoder;