support usage of gson without using dagger

CHANGES.md

@@ -1,3 +1,6 @@
+### Version 5.2.0
+* Support usage of `GsonCodec` via `Feign.Builder`
+
 ### Version 5.1.0
 * Correctly handle IOExceptions wrapped by Ribbon.
 * Miscellaneous findbugs fixes.

README.md

@@ -25,7 +25,9 @@ static class Contributor {
 }
 
 public static void main(String... args) {
-  GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GsonModule());
+  GitHub github = Feign.builder()
+                       .decoder(new GsonCodec())
+                       .target(GitHub.class, "https://api.github.com");
 
   // Fetch and print a list of the contributors to this library.
   List<Contributor> contributors = github.contributors("netflix", "feign");
@@ -35,8 +37,6 @@ public static void main(String... args) {
 }
 ```
 
-Feign includes a fully functional json codec in the `feign-gson` extension.  See the `Decoder` section for how to write your own.
-
 ### Customization
 
 Feign has several aspects that can be customized.  For simple cases, you can use `Feign.builder()` to construct an API interface with your custom components.  For example:
@@ -83,9 +83,14 @@ Feign intends to work well within Netflix and other Open Source communities.  Mo
 ### Gson
 [GsonModule](https://github.com/Netflix/feign/tree/master/gson) adds default encoders and decoders so you get get started with a JSON api.
 
-Integration requires you pass `new GsonModule()` to `Feign.create()`, or add it to your graph with Dagger:
+Add `GsonCodec` to your `Feign.Builder` like so:
+
 ```java
-GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GsonModule());
+GsonCodec codec = new GsonCodec();
+GitHub github = Feign.builder()
+                     .encoder(codec)
+                     .decoder(codec)
+                     .target(GitHub.class, "https://api.github.com");
 ```
 
 ### Sax
@@ -119,26 +124,16 @@ MyService api = Feign.create(MyService.class, "https://myAppProd", new RibbonMod
 ```
 
 ### Decoders
-The last argument to `Feign.create` allows you to specify additional configuration such as how to decode a responses, modeled in Dagger.
+`Feign.builder()` allows you to specify additional configuration such as how to decode a response.
 
 If any methods in your interface return types besides `Response` or `void`, you'll need to configure a `Decoder`.
 
-The `GsonModule` in the `feign-gson` extension configures a `Decoder` which parses objects from JSON using reflection.
+Here's how to configure json decoding (using the `feign-gson` extension):
 
-Here's how you could write this yourself, using whatever library you prefer:
 ```java
-@Module(library = true)
-static class JsonModule {
-  @Provides Decoder decoder(final JsonParser parser) {
-    return new Decoder() {
-
-      @Override public Object decode(Response response, Type type) throws IOException {
-        return parser.readJson(response.body().asReader(), type);
-      }
-
-    };
-  }
-}
+GitHub github = Feign.builder()
+                     .decoder(new GsonCodec())
+                     .target(GitHub.class, "https://api.github.com");
 ```
 
 ### Advanced usage and Dagger
@@ -166,15 +161,9 @@ Where possible, Feign configuration uses normal Dagger conventions.  For example
 #### Logging
 You can log the http messages going to and from the target by setting up a `Logger`.  Here's the easiest way to do that:
 ```java
-@Module(overrides = true)
-class Overrides {
-  @Provides @Singleton Logger.Level provideLoggerLevel() {
-    return Logger.Level.FULL;
-  }
-
-  @Provides @Singleton Logger provideLogger() {
-    return new Logger.JavaLogger().appendToFile("logs/http.log");
-  }
-}
-GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GsonGitHubModule(), new Overrides());
+GitHub github = Feign.builder()
+                     .decoder(new GsonCodec())
+                     .logger(new Logger.JavaLogger().appendToFile("logs/http.log"))
+                     .logLevel(Logger.Level.FULL)
+                     .target(GitHub.class, "https://api.github.com");
 ```

gson/README.md

@@ -3,7 +3,17 @@ Gson Codec
 
 This module adds support for encoding and decoding json via the Gson library.
 
-Add this to your object graph like so:
+Add `GsonCodec` to your `Feign.Builder` like so:
+
+```java
+GsonCodec codec = new GsonCodec();
+GitHub github = Feign.builder()
+                     .encoder(codec)
+                     .decoder(codec)
+                     .target(GitHub.class, "https://api.github.com");
+```
+
+Or.. to your object graph like so:
 
 ```java
 GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GsonModule());

gson/src/main/java/feign/gson/GsonCodec.java

@@ -0,0 +1,48 @@
+package feign.gson;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonIOException;
+import feign.RequestTemplate;
+import feign.Response;
+import feign.codec.Decoder;
+import feign.codec.Encoder;
+
+import javax.inject.Inject;
+import java.io.IOException;
+import java.io.Reader;
+import java.lang.reflect.Type;
+
+import static feign.Util.ensureClosed;
+
+public class GsonCodec implements Encoder, Decoder {
+  private final Gson gson;
+
+  public GsonCodec() {
+    this(new Gson());
+  }
+
+  @Inject public GsonCodec(Gson gson) {
+    this.gson = gson;
+  }
+
+  @Override public void encode(Object object, RequestTemplate template) {
+    template.body(gson.toJson(object));
+  }
+
+  @Override public Object decode(Response response, Type type) throws IOException {
+    if (response.body() == null) {
+      return null;
+    }
+    Reader reader = response.body().asReader();
+    try {
+      return gson.fromJson(reader, type);
+    } catch (JsonIOException e) {
+      if (e.getCause() != null && e.getCause() instanceof IOException) {
+        throw IOException.class.cast(e.getCause());
+      }
+      throw e;
+    } finally {
+      ensureClosed(reader);
+    }
+  }
+}

gson/src/main/java/feign/gson/GsonModule.java

@@ -18,7 +18,6 @@ package feign.gson;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.InstanceCreator;
-import com.google.gson.JsonIOException;
 import com.google.gson.TypeAdapter;
 import com.google.gson.internal.ConstructorConstructor;
 import com.google.gson.internal.bind.MapTypeAdapterFactory;
@@ -27,21 +26,16 @@ import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import dagger.Provides;
 import feign.Feign;
-import feign.RequestTemplate;
-import feign.Response;
 import feign.codec.Decoder;
 import feign.codec.Encoder;
 
-import javax.inject.Inject;
 import javax.inject.Singleton;
 import java.io.IOException;
-import java.io.Reader;
 import java.lang.reflect.Type;
 import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
 
-import static feign.Util.ensureClosed;
 import static feign.Util.resolveLastTypeParameter;
 
 /**
@@ -52,20 +46,20 @@ import static feign.Util.resolveLastTypeParameter;
  * to read numbers in a {@code Map<String, Object>} as Integers. You can
  * customize further by adding additional set bindings to the raw type
  * {@code TypeAdapter}.
- *
+ * <p/>
  * <br>
  * Here's an example of adding a custom json type adapter.
- * 
+ * <p/>
  * <pre>
  * &#064;Provides(type = Provides.Type.SET)
  * TypeAdapter upperZone() {
  *     return new TypeAdapter&lt;Zone&gt;() {
- * 
+ *
  *         &#064;Override
  *         public void write(JsonWriter out, Zone value) throws IOException {
  *             throw new IllegalArgumentException();
  *         }
- * 
+ *
  *         &#064;Override
  *         public Zone read(JsonReader in) throws IOException {
  *             in.beginObject();
@@ -91,41 +85,6 @@ public final class GsonModule {
     return codec;
   }
 
-  static class GsonCodec implements Encoder, Decoder {
-    private final Gson gson;
-
-    @Inject GsonCodec(Gson gson) {
-      this.gson = gson;
-    }
-
-    @Override public void encode(Object object, RequestTemplate template) {
-      template.body(gson.toJson(object));
-    }
-
-    @Override public Object decode(Response response, Type type) throws IOException {
-      if (response.body() == null) {
-        return null;
-      }
-      Reader reader = response.body().asReader();
-      try {
-        return fromJson(new JsonReader(reader), type);
-      } finally {
-        ensureClosed(reader);
-      }
-    }
-
-    private Object fromJson(JsonReader jsonReader, Type type) throws IOException {
-      try {
-        return gson.fromJson(jsonReader, type);
-      } catch (JsonIOException e) {
-        if (e.getCause() != null && e.getCause() instanceof IOException) {
-          throw IOException.class.cast(e.getCause());
-        }
-        throw e;
-      }
-    }
-  }
-
   @Provides @Singleton Gson gson(Set<TypeAdapter> adapters) {
     GsonBuilder builder = new GsonBuilder().setPrettyPrinting();
     for (TypeAdapter<?> adapter : adapters) {

gson/src/test/java/feign/gson/GsonModuleTest.java

@@ -52,8 +52,8 @@ public class GsonModuleTest {
     EncoderAndDecoderBindings bindings = new EncoderAndDecoderBindings();
     ObjectGraph.create(bindings).inject(bindings);
 
-    assertEquals(bindings.encoder.getClass(), GsonModule.GsonCodec.class);
-    assertEquals(bindings.decoder.getClass(), GsonModule.GsonCodec.class);
+    assertEquals(bindings.encoder.getClass(), GsonCodec.class);
+    assertEquals(bindings.decoder.getClass(), GsonCodec.class);
   }
 
   @Module(includes = GsonModule.class, injects = EncoderBindings.class)

gson/src/test/java/feign/gson/examples/GitHubExample.java

@@ -17,7 +17,7 @@ package feign.gson.examples;
 
 import feign.Feign;
 import feign.RequestLine;
-import feign.gson.GsonModule;
+import feign.gson.GsonCodec;
 
 import javax.inject.Named;
 import java.util.List;
@@ -38,7 +38,7 @@ public class GitHubExample {
   }
 
   public static void main(String... args) throws InterruptedException {
-    GitHub github = Feign.create(GitHub.class, "https://api.github.com", new GsonModule());
+    GitHub github = Feign.builder().decoder(new GsonCodec()).target(GitHub.class, "https://api.github.com");
 
     System.out.println("Let's fetch and print a list of the contributors to this library.");
     List<Contributor> contributors = github.contributors("netflix", "feign");