fix: use GrpaphQL execution context to resolve variable references (#129)

* fix: use GrpaphQL execution context to resolve variable references

* fix: remove redundant arguments

Author: igdianov

graphql-jpa-query-schema/src/main/java/com/introproventures/graphql/jpa/query/schema/impl/GraphQLJpaExecutor.java

@@ -23,7 +23,6 @@
 import javax.transaction.Transactional.TxType;
 
 import com.introproventures.graphql.jpa.query.schema.GraphQLExecutor;
-
 import graphql.ExecutionInput;
 import graphql.ExecutionResult;
 import graphql.GraphQL;
@@ -55,7 +54,7 @@ public GraphQLJpaExecutor(GraphQLSchema graphQLSchema) {
     @Override
     @Transactional(TxType.SUPPORTS)
     public ExecutionResult execute(String query) {
-        return graphQL.execute(query);
+        return execute(query, Collections.emptyMap());
     }
 
     /* (non-Javadoc)
@@ -65,20 +64,12 @@ public ExecutionResult execute(String query) {
     @Transactional(TxType.SUPPORTS)
     public ExecutionResult execute(String query, Map<String, Object> arguments) {
 
-    	// Need to inject variables in context to support parameter bindings in reverse queries 
-    	Map<String, Object> context = Collections.singletonMap("variables", arguments);
-    	
     	ExecutionInput executionInput = ExecutionInput.newExecutionInput()
     			.query(query)
     			.variables(arguments)
-    			.root(context)
-    			.context(context)
     			.build();
 
-        if (arguments == null)
-            return graphQL.execute(query);
-        else
-            return graphQL.execute(executionInput);
+        return graphQL.execute(executionInput);
     }
 
 }

graphql-jpa-query-schema/src/main/java/com/introproventures/graphql/jpa/query/schema/impl/QraphQLJpaBaseDataFetcher.java

@@ -309,15 +309,11 @@ protected Predicate getPredicate(CriteriaBuilder cb, Root<?> from, From<?,?> pat
 
                 From<?,?> join = getCompoundJoin(path, argument.getName(), true);
                 Argument where = new Argument("where",  argument.getValue());
-                Map<String, Object> variables = Optional.ofNullable(environment.getContext())
-                		.filter(it -> it instanceof Map)
-                		.map(it -> (Map<String, Object>) it)
-                		.map(it -> (Map<String, Object>) it.get("variables"))
-                		.orElse(Collections.emptyMap());
+                Map<String, Object> variables = environment.getExecutionContext().getVariables();
 
                 GraphQLFieldDefinition fieldDef = getFieldDef(
                     environment.getGraphQLSchema(),
-                    this.getObjectType(environment, argument),
+                    this.getObjectType(environment),
                     new Field(fieldName)
                 );
 
@@ -420,7 +416,7 @@ private Predicate getFieldPredicate(String fieldName, CriteriaBuilder cb, From<?
                           .anyMatch(it -> !Logical.names().contains(it.getName()) && !Criteria.names().contains(it.getName())))
         {
             GraphQLFieldDefinition fieldDefinition = getFieldDef(environment.getGraphQLSchema(),
-                                                                 this.getObjectType(environment, argument),
+                                                                 this.getObjectType(environment),
                                                                  new Field(fieldName));
             Map<String, Object> arguments = new LinkedHashMap<>();
             boolean isOptional = false;
@@ -580,7 +576,9 @@ protected Object convertValue(DataFetchingEnvironment environment, Argument argu
         }
         else if (value instanceof VariableReference) {
             Class javaType = getJavaType(environment, argument);
-            Object argumentValue = environment.getArguments().get(argument.getName());
+            Object argumentValue = environment.getExecutionContext()
+                                              .getVariables()
+                                              .get(VariableReference.class.cast(value).getName());
             if(javaType.isEnum()) {
                 if(argumentValue instanceof Collection) {
                     List<Enum> values = new ArrayList<>();
@@ -660,7 +658,7 @@ protected Class<?> getJavaType(DataFetchingEnvironment environment, Argument arg
      * @return JPA model attribute
      */
     private Attribute<?,?> getAttribute(DataFetchingEnvironment environment, Argument argument) {
-        GraphQLObjectType objectType = getObjectType(environment, argument);
+        GraphQLObjectType objectType = getObjectType(environment);
         EntityType<?> entityType = getEntityType(objectType);
 
         return entityType.getAttribute(argument.getName());
@@ -697,7 +695,7 @@ private EntityType<?> getEntityType(GraphQLObjectType objectType) {
      * @param argument
      * @return resolved GraphQL object type or null if no output type is provided
      */
-    private GraphQLObjectType getObjectType(DataFetchingEnvironment environment, Argument argument) {
+    private GraphQLObjectType getObjectType(DataFetchingEnvironment environment) {
         GraphQLType outputType = environment.getFieldType();
 
         if (outputType instanceof GraphQLList)