Added fetching from raw fields.

erikogenvik · erikogenvik · commit 345d92630d82 · 2015-09-15T13:12:35.000+02:00
The FieldDataFetcher will fetch data directly from raw fields.
It can be enabled by calling the "fetchField()" method on the field definition builder.
diff --git a/src/main/java/graphql/schema/FieldDataFetcher.java b/src/main/java/graphql/schema/FieldDataFetcher.java
@@ -0,0 +1,55 @@
+package graphql.schema;
+
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+
+import static graphql.Scalars.GraphQLBoolean;
+
+/**
+ * Fetches data directly from a field.
+ */
+public class FieldDataFetcher implements DataFetcher {
+
+    /**
+     * The name of the field.
+     */
+    private final String fieldName;
+
+    /**
+     * Ctor.
+     * @param fieldName The name of the field.
+     */
+    public FieldDataFetcher(String fieldName) {
+        this.fieldName = fieldName;
+    }
+
+    @Override
+    public Object get(DataFetchingEnvironment environment) {
+        Object source = environment.getSource();
+        if (source == null) return null;
+        if (source instanceof Map) {
+            return ((Map<?, ?>) source).get(fieldName);
+        }
+        return getFieldValue(source, environment.getFieldType());
+    }
+
+    /**
+     * Uses introspection to get the field value.
+     * @param object The object being acted on.
+     * @param outputType The output type; ignored in this case.
+     * @return An object, or null.
+     */
+    private Object getFieldValue(Object object, GraphQLOutputType outputType) {
+        try {
+            Field field = object.getClass().getField(fieldName);
+            return field.get(object);
+        } catch (NoSuchFieldException e) {
+            return null;
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
diff --git a/src/main/java/graphql/schema/GraphQLFieldDefinition.java b/src/main/java/graphql/schema/GraphQLFieldDefinition.java
@@ -83,6 +83,7 @@ public static class Builder {
         private DataFetcher dataFetcher;
         private List<GraphQLArgument> arguments = new ArrayList<>();
         private String deprecationReason;
+        private boolean isField;
 
 
         public Builder name(String name) {
@@ -115,6 +116,15 @@ public Object get(DataFetchingEnvironment environment) {
             return this;
         }
 
+        /**
+         * Get the data from a field.
+         * @return
+         */
+        public Builder fetchField() {
+            this.isField = true;
+            return this;
+        }
+
         public Builder argument(GraphQLArgument argument) {
             this.arguments.add(argument);
             return this;
@@ -132,7 +142,11 @@ public Builder deprecate(String deprecationReason) {
 
         public GraphQLFieldDefinition build() {
             if (dataFetcher == null) {
-                dataFetcher = new PropertyDataFetcher(name);
+                if (isField) {
+                    dataFetcher = new FieldDataFetcher(name);
+                } else {
+                    dataFetcher = new PropertyDataFetcher(name);
+                }
             }
             return new GraphQLFieldDefinition(name, description, type, dataFetcher, arguments, deprecationReason);
         }
diff --git a/src/test/groovy/graphql/DataFetcherTest.groovy b/src/test/groovy/graphql/DataFetcherTest.groovy
@@ -0,0 +1,50 @@
+package graphql
+
+import graphql.schema.DataFetchingEnvironment
+import graphql.schema.FieldDataFetcher
+import graphql.schema.PropertyDataFetcher
+import spock.lang.Specification
+
+import static graphql.Scalars.GraphQLString
+
+class DataFetcherTest extends Specification {
+
+    class DataHolder {
+
+        private String privateField
+        public String publicField
+
+        public String getProperty() {
+            return privateField
+        }
+
+        public void setProperty(String value) {
+            privateField = value
+        }
+    }
+    def DataHolder dataHolder
+
+    def setup() {
+        dataHolder = new DataHolder();
+        dataHolder.publicField = "publicValue"
+        dataHolder.setProperty("propertyValue")
+    }
+
+    def "get field value"() {
+        given:
+        def environment = new DataFetchingEnvironment(dataHolder, null, null, null, GraphQLString, null, null)
+        when:
+        def result = new FieldDataFetcher("publicField").get(environment)
+        then:
+        result == "publicValue"
+    }
+
+    def "get property value"() {
+        given:
+        def environment = new DataFetchingEnvironment(dataHolder, null, null, null, GraphQLString, null, null)
+        when:
+        def result = new PropertyDataFetcher("property").get(environment)
+        then:
+        result == "propertyValue"
+    }
+}
