From 872046ed4c6fbf1cde4c224f50d906dec3c196d4 Mon Sep 17 00:00:00 2001
From: Adrian Cole <adrian@jclouds.org>
Date: Sun, 15 Jul 2012 20:10:49 -0700
Subject: [PATCH] added @Transform

---
 .../jclouds/rest/annotations/Transform.java   | 38 +++++++++++++++++++
 .../internal/RestAnnotationProcessor.java     |  6 +++
 .../internal/RestAnnotationProcessorTest.java | 27 +++++++++++++
 3 files changed, 71 insertions(+)
 create mode 100644 core/src/main/java/org/jclouds/rest/annotations/Transform.java

diff --git a/core/src/main/java/org/jclouds/rest/annotations/Transform.java b/core/src/main/java/org/jclouds/rest/annotations/Transform.java
new file mode 100644
index 0000000000..684b809b81
--- /dev/null
+++ b/core/src/main/java/org/jclouds/rest/annotations/Transform.java
@@ -0,0 +1,38 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.rest.annotations;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import com.google.common.base.Function;
+
+/**
+ * Shows the transformer type used to parse the first result of the HttpResponse
+ * 
+ * @author Adrian Cole
+ */
+@Target(METHOD)
+@Retention(RUNTIME)
+public @interface Transform {
+   Class<? extends Function<?, ?>> value();
+}
diff --git a/core/src/main/java/org/jclouds/rest/internal/RestAnnotationProcessor.java b/core/src/main/java/org/jclouds/rest/internal/RestAnnotationProcessor.java
index fe5b28992a..44bdbcc71b 100644
--- a/core/src/main/java/org/jclouds/rest/internal/RestAnnotationProcessor.java
+++ b/core/src/main/java/org/jclouds/rest/internal/RestAnnotationProcessor.java
@@ -124,6 +124,7 @@ import org.jclouds.rest.annotations.RequestFilters;
 import org.jclouds.rest.annotations.ResponseParser;
 import org.jclouds.rest.annotations.SelectJson;
 import org.jclouds.rest.annotations.SkipEncoding;
+import org.jclouds.rest.annotations.Transform;
 import org.jclouds.rest.annotations.Unwrap;
 import org.jclouds.rest.annotations.VirtualHost;
 import org.jclouds.rest.annotations.WrapWith;
@@ -298,6 +299,11 @@ public class RestAnnotationProcessor<T> {
       } else {
          transformer = injector.getInstance(getParserOrThrowException(method));
       }
+      if (method.isAnnotationPresent(Transform.class)) {
+         transformer = Functions
+                  .compose(Function.class.cast(injector.getInstance(method.getAnnotation(Transform.class).value())),
+                           transformer);
+      }
       return transformer;
    }
 
diff --git a/core/src/test/java/org/jclouds/rest/internal/RestAnnotationProcessorTest.java b/core/src/test/java/org/jclouds/rest/internal/RestAnnotationProcessorTest.java
index 4069e13d23..02258207d0 100644
--- a/core/src/test/java/org/jclouds/rest/internal/RestAnnotationProcessorTest.java
+++ b/core/src/test/java/org/jclouds/rest/internal/RestAnnotationProcessorTest.java
@@ -125,6 +125,7 @@ import org.jclouds.rest.annotations.RequestFilters;
 import org.jclouds.rest.annotations.ResponseParser;
 import org.jclouds.rest.annotations.SelectJson;
 import org.jclouds.rest.annotations.SkipEncoding;
+import org.jclouds.rest.annotations.Transform;
 import org.jclouds.rest.annotations.Unwrap;
 import org.jclouds.rest.annotations.VirtualHost;
 import org.jclouds.rest.annotations.WrapWith;
@@ -1037,6 +1038,20 @@ public class RestAnnotationProcessorTest extends BaseRestApiTest {
       @SelectJson("jobid")
       ListenableFuture<Long> selectLong();
 
+      @GET
+      @Path("/")
+      @SelectJson("jobid")
+      @Transform(AddOne.class)
+      ListenableFuture<Long> selectLongAddOne();
+
+      static class AddOne implements Function<Long, Long> {
+
+         @Override
+         public Long apply(Long o) {
+            return o + 1;
+         }
+      }
+
       @GET
       @Path("/")
       @SelectJson("runit")
@@ -1262,6 +1277,18 @@ public class RestAnnotationProcessorTest extends BaseRestApiTest {
             .payload("{ \"destroyvirtualmachineresponse\" : {\"jobid\":4} }").build()), new Long(4));
    }
 
+   @SuppressWarnings("unchecked")
+   public void selectLongAddOne() throws SecurityException, NoSuchMethodException, IOException {
+      Method method = TestPut.class.getMethod("selectLongAddOne");
+      HttpRequest request = factory(TestPut.class).createRequest(method);
+
+      Function<HttpResponse, Map<String, String>> parser = (Function<HttpResponse, Map<String, String>>) RestAnnotationProcessor
+            .createResponseParser(parserFactory, injector, method, request);
+
+      assertEquals(parser.apply(HttpResponse.builder().statusCode(200).message("ok")
+            .payload("{ \"destroyvirtualmachineresponse\" : {\"jobid\":4} }").build()), new Long(5));
+   }
+   
    static class TestRequestFilter1 implements HttpRequestFilter {
       public HttpRequest filter(HttpRequest request) throws HttpException {
          return request;