graphql-java · bbakerman · Feb 1, 2022 · Dec 20, 2021
diff --git a/src/main/java/graphql/GraphqlErrorBuilder.java b/src/main/java/graphql/GraphqlErrorBuilder.java
@@ -14,22 +14,44 @@
 /**
  * This helps you build {@link graphql.GraphQLError}s and also has a quick way to make a  {@link graphql.execution.DataFetcherResult}s
  * from that error.
+ *
+ * @param <B> this base class allows you to derive new classes from this base error builder
  */
+@SuppressWarnings("unchecked")
 @PublicApi
-public class GraphqlErrorBuilder {
+public class GraphqlErrorBuilder<B extends GraphqlErrorBuilder<?>> {
 
     private String message;
     private List<Object> path;
     private List<SourceLocation> locations = new ArrayList<>();
     private ErrorClassification errorType = ErrorType.DataFetchingException;
     private Map<String, Object> extensions = null;
 
+    public String getMessage() {
+        return message;
+    }
+
+    public List<Object> getPath() {
+        return path;
+    }
+
+    public List<SourceLocation> getLocations() {
+        return locations;
+    }
+
+    public ErrorClassification getErrorType() {
+        return errorType;
+    }
+
+    public Map<String, Object> getExtensions() {
+        return extensions;
+    }
 
     /**
      * @return a builder of {@link graphql.GraphQLError}s
      */
-    public static GraphqlErrorBuilder newError() {
-        return new GraphqlErrorBuilder();
+    public static GraphqlErrorBuilder<?> newError() {
+        return new GraphqlErrorBuilder<>();
     }
 
     /**
@@ -40,52 +62,52 @@ public static GraphqlErrorBuilder newError() {
      *
      * @return a builder of {@link graphql.GraphQLError}s
      */
-    public static GraphqlErrorBuilder newError(DataFetchingEnvironment dataFetchingEnvironment) {
-        return new GraphqlErrorBuilder()
+    public static GraphqlErrorBuilder<?> newError(DataFetchingEnvironment dataFetchingEnvironment) {
+        return new GraphqlErrorBuilder<>()
                 .location(dataFetchingEnvironment.getField().getSourceLocation())
                 .path(dataFetchingEnvironment.getExecutionStepInfo().getPath());
     }
 
-    private GraphqlErrorBuilder() {
+    protected GraphqlErrorBuilder() {
     }
 
-    public GraphqlErrorBuilder message(String message, Object... formatArgs) {
+    public B message(String message, Object... formatArgs) {
         if (formatArgs == null || formatArgs.length == 0) {
             this.message = assertNotNull(message);
         } else {
             this.message = String.format(assertNotNull(message), formatArgs);
         }
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder locations(List<SourceLocation> locations) {
+    public B locations(List<SourceLocation> locations) {
         this.locations.addAll(assertNotNull(locations));
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder location(SourceLocation location) {
+    public B location(SourceLocation location) {
         this.locations.add(assertNotNull(location));
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder path(ResultPath path) {
+    public B path(ResultPath path) {
         this.path = assertNotNull(path).toList();
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder path(List<Object> path) {
+    public B path(List<Object> path) {
         this.path = assertNotNull(path);
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder errorType(ErrorClassification errorType) {
+    public B errorType(ErrorClassification errorType) {
         this.errorType = assertNotNull(errorType);
-        return this;
+        return (B) this;
     }
 
-    public GraphqlErrorBuilder extensions(Map<String, Object> extensions) {
+    public B extensions(Map<String, Object> extensions) {
         this.extensions = assertNotNull(extensions);
-        return this;
+        return (B) this;
     }
 
     /**
@@ -147,7 +169,7 @@ public String toString() {
      *
      * @return a new data fetcher result that contains the built error
      */
-    public DataFetcherResult toResult() {
+    public DataFetcherResult<?> toResult() {
         return DataFetcherResult.newResult()
                 .error(build())
                 .build();

diff --git a/src/test/groovy/graphql/GraphqlErrorBuilderTest.groovy b/src/test/groovy/graphql/GraphqlErrorBuilderTest.groovy
@@ -39,6 +39,19 @@ class GraphqlErrorBuilderTest extends Specification {
         graphQLError.getErrorType() == ErrorType.DataFetchingException
     }
 
+    def "builder getters work"() {
+        when:
+        def errorBuilder = GraphqlErrorBuilder.newError()
+                .message("Gunfight at the %s corral", "NotOK")
+                .location(location)
+                .path(["a","b"])
+        then:
+        errorBuilder.getMessage() == "Gunfight at the NotOK corral"
+        errorBuilder.getErrorType() == ErrorType.DataFetchingException
+        errorBuilder.getPath() == ["a","b"]
+        errorBuilder.getLocations() == [location]
+    }
+
     def "data fetcher result building works"() {
         when:
         def result = GraphqlErrorBuilder.newError().message("Gunfight at the %s corral", "NotOK").toResult()

diff --git a/src/test/groovy/readme/ReadmeExamples.java b/src/test/groovy/readme/ReadmeExamples.java
@@ -1,5 +1,8 @@
 package readme;
 
+import graphql.GraphQLError;
+import graphql.GraphqlErrorBuilder;
+import graphql.InvalidSyntaxError;
 import graphql.Scalars;
 import graphql.StarWarsData;
 import graphql.TypeResolutionEnvironment;
@@ -448,6 +451,27 @@ public GraphQLObjectType getType(TypeResolutionEnvironment env) {
         };
     }
 
+    static class SpecialError extends InvalidSyntaxError {
+
+        public SpecialError(SpecialErrorBuilder builder) {
+            super(builder.getLocations(), builder.getMessage());
+        }
+    }
+
+    static class SpecialErrorBuilder extends GraphqlErrorBuilder<SpecialErrorBuilder> {
+
+        @Override
+        public SpecialError build() {
+            return new SpecialError(this);
+        }
+    }
+
+    private void errorBuilderExample() {
+        GraphQLError err = GraphqlErrorBuilder.newError().message("direct").build();
+
+        SpecialError specialErr = new SpecialErrorBuilder().message("special").build();
+    }
+
     private DataFetcher createDataFetcher(FieldDefinition definition, Directive directive) {
         throw new UnsupportedOperationException("Not implemented");
     }