improve javadoc

andimarek · andimarek · commit 1399e499eede · 2017-06-02T03:14:27.000+02:00
diff --git a/src/main/java/graphql/schema/DataFetchingEnvironment.java b/src/main/java/graphql/schema/DataFetchingEnvironment.java
@@ -13,9 +13,15 @@
  */
 @PublicApi
 public interface DataFetchingEnvironment {
+
     /**
+     * This is the value of the current object to be queried.
+     * Or to put it differently: it is the value of the parent field.
+     * <p>
+     * For the root query, it is equal to {{@link DataFetchingEnvironment#getRoot}
+     *
      * @param <T> you decide what type it is
-     * @return the current object being queried
+     * @return can be null for the root query, otherwise it is never null
      */
     <T> T getSource();
 
@@ -42,14 +48,22 @@ public interface DataFetchingEnvironment {
     <T> T getArgument(String name);
 
     /**
-     * Returns a context argument that is set up when the {@link graphql.GraphQL#execute(String, Object)} method
-     * is invoked
+     * Returns a context argument that is set up when the {@link graphql.GraphQL#execute} method
+     * is invoked.
+     * <p>
+     * This is a info object which is provided to all DataFetcher, but never used by graphql-java itself.
      *
      * @param <T> you decide what type it is
-     * @return a context object
+     * @return can be null
      */
     <T> T getContext();
 
+    /**
+     * This is the source object for the root query.
+     *
+     * @param <T>
+     * @return can be null
+     */
     <T> T getRoot();
 
     /**
