Flexible description annotation (#63)

* add test for description

* allow @GraphQLDescription to be on methods

* search for @GraphQLDescription on the given Member's getter Method or Field

* test descriptions on getters are picked up

* test more combinations of JPA and Description annotation placement

Author: molexx

graphql-jpa-query-annotations/src/main/java/com/introproventures/graphql/jpa/query/annotation/GraphQLDescription.java

@@ -17,6 +17,7 @@
 
 import static java.lang.annotation.ElementType.FIELD;
 import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.ElementType.METHOD;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
 import java.lang.annotation.Retention;
@@ -28,7 +29,7 @@
  * @author Igor Dianov
  *
  */
-@Target( { TYPE, FIELD })
+@Target( { TYPE, FIELD, METHOD })
 @Retention(RUNTIME)
 public @interface GraphQLDescription {
 

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

@@ -16,9 +16,14 @@
 
 package com.introproventures.graphql.jpa.query.schema.impl;
 
+import java.beans.BeanInfo;
+import java.beans.IntrospectionException;
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
 import java.lang.reflect.AnnotatedElement;
 import java.lang.reflect.Field;
 import java.lang.reflect.Member;
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -572,7 +577,68 @@ protected final boolean isValidInput(Attribute<?,?> attribute) {
 
     private String getSchemaDescription(Member member) {
         if (member instanceof AnnotatedElement) {
-            return getSchemaDescription((AnnotatedElement) member);
+            String desc = getSchemaDescription((AnnotatedElement) member);
+            if (desc != null) {
+                return(desc);
+            }
+        }
+
+        //The given Member has no @GraphQLDescription set.
+        //If the Member is a Method it might be a getter/setter, see if the property it represents
+        //is annotated with @GraphQLDescription
+        //Alternatively if the Member is a Field its getter might be annotated, see if its getter
+        //is annotated with @GraphQLDescription
+        if (member instanceof Method) {
+            Field fieldMember = getFieldByAccessor((Method)member);
+            if (fieldMember != null) {
+                return(getSchemaDescription((AnnotatedElement) fieldMember));
+            }
+        } else if (member instanceof Field) {
+            Method fieldGetter = getGetterOfField((Field)member);
+            if (fieldGetter != null) {
+                return(getSchemaDescription((AnnotatedElement) fieldGetter));
+            }
+        }
+
+        return null;
+    }
+
+    private Method getGetterOfField(Field field) {
+        try {
+            Class<?> clazz = field.getDeclaringClass();
+            BeanInfo info = Introspector.getBeanInfo(clazz);
+            PropertyDescriptor[] props = info.getPropertyDescriptors();
+            for (PropertyDescriptor pd : props) { 
+                if (pd.getName().equals(field.getName())) {
+                    return(pd.getReadMethod());
+                }
+            }
+        } catch (IntrospectionException e) {
+            e.printStackTrace();
+        }
+
+        return(null);
+    }
+
+    //from https://stackoverflow.com/questions/13192734/getting-a-property-field-name-using-getter-method-of-a-pojo-java-bean/13514566
+    private static Field getFieldByAccessor(Method method) {
+        try {
+            Class<?> clazz = method.getDeclaringClass();
+            BeanInfo info = Introspector.getBeanInfo(clazz);  
+            PropertyDescriptor[] props = info.getPropertyDescriptors();  
+            for (PropertyDescriptor pd : props) {  
+                if(method.equals(pd.getWriteMethod()) || method.equals(pd.getReadMethod())) {
+                    String fieldName = pd.getName();
+                    try {
+                        return(clazz.getDeclaredField(fieldName));
+                    } catch (Throwable t) {
+                        log.error("class '" + clazz.getName() + "' contains method '" + method.getName() + "' which is an accessor for a Field named '" + fieldName + "', error getting the field:", t);
+                        return(null);
+                    }
+                }
+            }
+        } catch (Throwable t)  {
+            log.error("error finding Field for accessor with name '" + method.getName() + "'", t);
         }
 
         return null;

graphql-jpa-query-schema/src/test/java/com/introproventures/graphql/jpa/query/schema/StarwarsSchemaBuildTest.java

@@ -35,6 +35,7 @@
 import graphql.Scalars;
 import graphql.schema.GraphQLInputObjectType;
 import graphql.schema.GraphQLSchema;
+import graphql.schema.GraphQLObjectType;
 
 @RunWith(SpringRunner.class)
 @SpringBootTest(
@@ -120,4 +121,66 @@ public void correctlyDerivesPageableSchemaFromGivenEntities() {
 
     }
 
+    
+    @Test
+    public void correctlyDerivesSchemaDescriptionsFromGivenEntities() {
+        //when
+        GraphQLSchema schema = builder.build();
+
+        // then
+        assertThat(schema)
+            .describedAs("Ensure the schema is generated")
+            .isNotNull();
+
+        //then
+        assertThat(schema.getQueryType().getFieldDefinition("Droid").getDescription())
+            .describedAs( "Ensure that Droid has the expected description")
+            .isEqualTo("Represents an electromechanical robot in the Star Wars Universe");
+        
+        //then
+        assertThat(
+                ((GraphQLObjectType)schema.getQueryType().getFieldDefinition("Droid").getType())
+                .getFieldDefinition("primaryFunction")
+                .getDescription()
+        )
+            .describedAs( "Ensure that Droid.primaryFunction has the expected description")
+            .isEqualTo("Documents the primary purpose this droid serves");
+
+        //then
+        assertThat(
+                ((GraphQLObjectType)schema.getQueryType().getFieldDefinition("Droid").getType())
+                        .getFieldDefinition("id")
+                        .getDescription()
+        )
+                .describedAs( "Ensure that Droid.id has the expected description, inherited from Character")
+                .isEqualTo("Primary Key for the Character Class");
+        
+        //then
+        assertThat(
+                ((GraphQLObjectType)schema.getQueryType().getFieldDefinition("Droid").getType())
+                        .getFieldDefinition("name")
+                        .getDescription()
+        )
+                .describedAs( "Ensure that Droid.name has the expected description, inherited from Character")
+                .isEqualTo("Name of the character");
+
+        //then
+        assertThat(
+                ((GraphQLObjectType)schema.getQueryType().getFieldDefinition("CodeList").getType())
+                        .getFieldDefinition("id")
+                        .getDescription()
+        )
+                .describedAs( "Ensure that CodeList.id has the expected description")
+                .isEqualTo("Primary Key for the Code List Class");
+        
+        //then
+        assertThat(
+                ((GraphQLObjectType)schema.getQueryType().getFieldDefinition("CodeList").getType())
+                        .getFieldDefinition("parent")
+                        .getDescription()
+        )
+                .describedAs( "Ensure that CodeList.parent has the expected description")
+                .isEqualTo("The CodeList's parent CodeList");
+    }
+    
 }

graphql-jpa-query-schema/src/test/java/com/introproventures/graphql/jpa/query/schema/model/starwars/CodeList.java

@@ -31,7 +31,6 @@
 @Data
 public class CodeList {
 
-    @Id
     @GraphQLDescription("Primary Key for the Code List Class")
     Long id;
 
@@ -41,8 +40,18 @@ public class CodeList {
     boolean active;
     String description;
 
-    @ManyToOne(fetch=FetchType.LAZY)
-    @JoinColumn(name = "parent_id")
     CodeList parent;
 
+    //JPA annotations moved to getters to test that @GraphQLDescription can be placed on the field when the JPA annotation is on the getter
+    @Id
+    public Long getId() {
+        return(id);
+    }
+    
+    @ManyToOne(fetch=FetchType.LAZY)
+    @JoinColumn(name = "parent_id")
+    @GraphQLDescription("The CodeList's parent CodeList")
+    public CodeList getParent() {
+        return(parent);
+    }
 }

graphql-jpa-query-schema/src/test/java/com/introproventures/graphql/jpa/query/schema/model/starwars/Droid.java

@@ -29,7 +29,11 @@
 @EqualsAndHashCode(callSuper=true)
 public class Droid extends Character {
 
-    @GraphQLDescription("Documents the primary purpose this droid serves")
     String primaryFunction;
 
+    //description moved to getter to test it gets picked up
+    @GraphQLDescription("Documents the primary purpose this droid serves")
+    public String getPrimaryFunction() {
+        return(primaryFunction);
+    }
 }