Problem: GraphQLDataFetcher use with respect to names is overly verbose/repetitive

Solution: Enhance the GraphQLDataFetcher annotation to optionally pass it's
target's name as the first 'arg' to the DataFetcher's constructor.

Author: Sean Brandt

src/main/java/graphql/annotations/GraphQLAnnotations.java

@@ -52,6 +52,7 @@
 import java.util.TreeMap;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import static graphql.Scalars.GraphQLBoolean;
 import static graphql.annotations.ReflectionKit.constructNewInstance;
@@ -326,7 +327,12 @@ protected GraphQLFieldDefinition getField(Field field) throws GraphQLAnnotations
         GraphQLDataFetcher dataFetcher = field.getAnnotation(GraphQLDataFetcher.class);
         DataFetcher actualDataFetcher = null;
         if (nonNull(dataFetcher)) {
-            final String[] args = dataFetcher.args();
+            final String[] args;
+            if ( dataFetcher.firstArgIsTargetName() ) {
+                args = Stream.concat(Stream.of(field.getName()), stream(dataFetcher.args())).toArray(String[]::new);
+            } else {
+                args = dataFetcher.args();
+            }
             if (args.length == 0) {
                 actualDataFetcher = newInstance(dataFetcher.value());
             } else {

src/main/java/graphql/annotations/GraphQLDataFetcher.java

@@ -26,4 +26,5 @@
 public @interface GraphQLDataFetcher {
     Class<? extends DataFetcher> value();
     String[] args() default {};
+    boolean firstArgIsTargetName() default false;
 }

src/test/java/graphql/annotations/GraphQLDataFetcherTest.java

@@ -26,6 +26,7 @@
 import org.testng.annotations.Test;
 
 import static graphql.schema.GraphQLSchema.newSchema;
+import static org.testng.Assert.assertFalse;
 import static org.testng.Assert.assertNotNull;
 import static org.testng.Assert.assertTrue;
 
@@ -39,12 +40,13 @@ public void shouldUsePreferredConstructor() {
     final GraphQL graphql = new GraphQL(schema);
 
     // When
-    final ExecutionResult result = graphql.execute("{sample {isGreat}}");
+    final ExecutionResult result = graphql.execute("{sample {isGreat isBad}}");
 
     // Then
     final HashMap<String, Object> data = (HashMap) result.getData();
     assertNotNull(data);
     assertTrue(((HashMap<String,Boolean>)data.get("sample")).get("isGreat"));
+    assertTrue(((HashMap<String,Boolean>)data.get("sample")).get("isBad"));
   }
 
   @GraphQLName("Query")
@@ -60,6 +62,11 @@ public static class TestSample {
     @GraphQLField
     @GraphQLDataFetcher(value = PropertyDataFetcher.class, args = "isGreat")
     private Boolean isGreat = false; // Defaults to FieldDataFetcher
+
+    @GraphQLField
+    @GraphQLDataFetcher(value = SampleMultiArgDataFetcher.class, firstArgIsTargetName = true, args = {"true"})
+    private Boolean isBad = false; // Defaults to FieldDataFetcher
+
   }
 
   public static class SampleDataFetcher implements DataFetcher {
@@ -69,8 +76,28 @@ public Object get(final DataFetchingEnvironment environment) {
     }
   }
 
+  public static class SampleMultiArgDataFetcher extends PropertyDataFetcher {
+    private boolean flip = false;
+
+    public SampleMultiArgDataFetcher(String target, String flip) {
+      super(target);
+      this.flip = Boolean.valueOf(flip);
+    }
+
+    @Override
+    public Object get(DataFetchingEnvironment environment) {
+      final Object result = super.get(environment);
+      if ( flip ) {
+        return !(Boolean)result;
+      } else {
+        return result;
+      }
+    }
+  }
+
   public static class Sample {
     private Boolean isGreat = true;
+    private Boolean isBad = false;
 
     public Boolean getIsGreat() {
       return isGreat;
@@ -79,5 +106,13 @@ public Boolean getIsGreat() {
     public void setIsGreat(final Boolean isGreat) {
       this.isGreat = isGreat;
     }
+
+    public Boolean getIsBad() {
+      return isBad;
+    }
+
+    public void setIsBad(Boolean bad) {
+      isBad = bad;
+    }
   }
-}
+}