Simplify Decoder.Default by extending StringDecoder

davidmc24 · davidmc24 · commit a4583722baee · 2013-09-22T19:02:26.000-04:00
Previously, the default decoder had logic relating to responses that made it distinct from StringDecoder.
Now that that's handled elsewhere, the body of the decode methods had less meaningful differences.
I opted to maintain Decoder.Default for consistency with other default implementations.  StringDecoder
is maintained as a separate class for backwards compatibility, and because it may be useful in the
future for clients to use a plain String decoder even if the default decoder starts having additional
capabilities.
diff --git a/core/src/main/java/feign/Util.java b/core/src/main/java/feign/Util.java
@@ -168,6 +168,9 @@ public static Type resolveLastTypeParameter(Type genericContext, Class<?> supert
 
   private static final int BUF_SIZE = 0x800; // 2K chars (4K bytes)
 
+  /**
+   * Adapted from {@code com.google.common.io.CharStreams.toString()}.
+   */
   public static String toString(Reader reader) throws IOException {
     if (reader == null) {
       return null;
diff --git a/core/src/main/java/feign/codec/Decoder.java b/core/src/main/java/feign/codec/Decoder.java
@@ -17,13 +17,10 @@
 
 import feign.FeignException;
 import feign.Response;
-import feign.Util;
 
 import java.io.IOException;
 import java.lang.reflect.Type;
 
-import static java.lang.String.format;
-
 /**
  * Decodes an HTTP response into a single object of the given {@code type}. Invoked when
  * {@link Response#status()} is in the 2xx range and the return type is neither {@code void} nor {@code Response}.
@@ -76,17 +73,8 @@ public interface Decoder {
   Object decode(Response response, Type type) throws IOException, DecodeException, FeignException;
 
   /**
-   * Default implementation of {@code Decoder} that supports {@code String} signatures.
+   * Default implementation of {@code Decoder}.
    */
-  public class Default implements Decoder {
-    @Override
-    public Object decode(Response response, Type type) throws IOException {
-      if (response.body() == null) {
-        return null;
-      } else if (String.class.equals(type)) {
-        return Util.toString(response.body().asReader());
-      }
-      throw new DecodeException(format("%s is not a type supported by this decoder.", type));
-    }
+  public class Default extends StringDecoder {
   }
 }
diff --git a/core/src/main/java/feign/codec/StringDecoder.java b/core/src/main/java/feign/codec/StringDecoder.java
@@ -21,16 +21,18 @@
 import java.io.IOException;
 import java.lang.reflect.Type;
 
-/**
- * Adapted from {@code com.google.common.io.CharStreams.toString()}.
- */
+import static java.lang.String.format;
+
 public class StringDecoder implements Decoder {
   @Override
   public Object decode(Response response, Type type) throws IOException {
     Response.Body body = response.body();
     if (body == null) {
       return null;
     }
-    return Util.toString(body.asReader());
+    if (String.class.equals(type)) {
+      return Util.toString(body.asReader());
+    }
+    throw new DecodeException(format("%s is not a type supported by this decoder.", type));
   }
 }
diff --git a/core/src/test/java/feign/codec/DefaultDecoderTest.java b/core/src/test/java/feign/codec/DefaultDecoderTest.java
@@ -16,7 +16,6 @@
 package feign.codec;
 
 import feign.Response;
-import feign.Util;
 import org.testng.annotations.Test;
 import org.w3c.dom.Document;
 
