Add default methods to HttpClient and AsyncHttpClient

HorizonApache/src/main/java/com/hubspot/horizon/apache/ApacheHttpClient.java

@@ -143,11 +143,6 @@ private SocketConfig createSocketConfig(HttpConfig config) {
     return SocketConfig.custom().setSoTimeout(config.getRequestTimeoutMillis()).build();
   }
 
-  @Override
-  public HttpResponse execute(HttpRequest request) throws HttpRuntimeException {
-    return execute(Preconditions.checkNotNull(request), Options.DEFAULT);
-  }
-
   @Override
   public HttpResponse execute(HttpRequest request, Options options)
     throws HttpRuntimeException {

HorizonCore/src/main/java/com/hubspot/horizon/AsyncHttpClient.java

@@ -1,14 +1,45 @@
 package com.hubspot.horizon;
 
 import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.SettableFuture;
 import com.hubspot.horizon.HttpRequest.Options;
 import java.io.Closeable;
 
 public interface AsyncHttpClient extends Closeable {
-  ListenableFuture<HttpResponse> execute(HttpRequest request);
-  ListenableFuture<HttpResponse> execute(HttpRequest request, Options options);
+  default ListenableFuture<HttpResponse> execute(HttpRequest request) {
+    return execute(request, Options.DEFAULT);
+  }
+
+  default ListenableFuture<HttpResponse> execute(HttpRequest request, Options options) {
+    SettableFuture<HttpResponse> responseFuture = SettableFuture.create();
+
+    try {
+      execute(
+        request,
+        options,
+        new Callback() {
+          @Override
+          public void completed(HttpResponse response) {
+            responseFuture.set(response);
+          }
+
+          @Override
+          public void failed(Exception e) {
+            responseFuture.setException(e);
+          }
+        }
+      );
+    } catch (HttpRuntimeException e) {
+      responseFuture.setException(e);
+    }
+
+    return responseFuture;
+  }
+
+  default void execute(HttpRequest request, Callback callback) {
+    execute(request, Options.DEFAULT, callback);
+  }
 
-  void execute(HttpRequest request, Callback callback);
   void execute(HttpRequest request, Options options, Callback callback);
 
   interface Callback {

HorizonCore/src/main/java/com/hubspot/horizon/HttpClient.java

@@ -4,6 +4,9 @@
 import java.io.Closeable;
 
 public interface HttpClient extends Closeable {
-  HttpResponse execute(HttpRequest request) throws HttpRuntimeException;
+  default HttpResponse execute(HttpRequest request) throws HttpRuntimeException {
+    return execute(request, Options.DEFAULT);
+  }
+
   HttpResponse execute(HttpRequest request, Options options) throws HttpRuntimeException;
 }

HorizonCore/src/main/java/com/hubspot/horizon/HttpRequest.java

@@ -133,7 +133,7 @@ public Options getOptions() {
 
   public static class Options {
 
-    public static Options DEFAULT = new Options();
+    public static final Options DEFAULT = new Options();
 
     private Optional<Integer> maxRetries = Optional.absent();
     private Optional<Integer> initialRetryBackoffSeconds = Optional.absent();

HorizonNing/src/main/java/com/hubspot/horizon/ning/NingAsyncHttpClient.java

@@ -108,21 +108,11 @@ public NingAsyncHttpClient(HttpConfig config) {
     this.mapper = config.getObjectMapper();
   }
 
-  @Override
-  public ListenableFuture<HttpResponse> execute(HttpRequest request) {
-    return execute(Preconditions.checkNotNull(request), Options.DEFAULT);
-  }
-
   @Override
   public ListenableFuture<HttpResponse> execute(HttpRequest request, Options options) {
     return internalExecute(request, options, EmptyCallback.INSTANCE);
   }
 
-  @Override
-  public void execute(HttpRequest request, Callback callback) {
-    execute(Preconditions.checkNotNull(request), Options.DEFAULT, callback);
-  }
-
   @Override
   public void execute(HttpRequest request, Options options, Callback callback) {
     internalExecute(request, options, callback);

HorizonNing/src/main/java/com/hubspot/horizon/ning/NingHttpClient.java

@@ -22,11 +22,6 @@ public NingHttpClient(HttpConfig config) {
     this.delegate = new NingAsyncHttpClient(Preconditions.checkNotNull(config));
   }
 
-  @Override
-  public HttpResponse execute(HttpRequest request) throws HttpRuntimeException {
-    return execute(Preconditions.checkNotNull(request), Options.DEFAULT);
-  }
-
   @Override
   public HttpResponse execute(HttpRequest request, Options options)
     throws HttpRuntimeException {