Refactoring in argument binding

GraphQlArgumentBinder allows external determination of the raw value to use,
and ArgumentMethodArgumentResolver allows customizing the invocation of
the binder.

See gh-864

Author: rstoyanchev

spring-graphql/src/main/java/org/springframework/graphql/data/GraphQlArgumentBinder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2023 the original author or authors.
+ * Copyright 2020-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -142,6 +142,19 @@ public Object bind(
 		Object rawValue = (name != null ? environment.getArgument(name) : environment.getArguments());
 		boolean isOmitted = (name != null && !environment.getArguments().containsKey(name));
 
+		return bind(name, rawValue, isOmitted, targetType);
+	}
+
+	/**
+	 * Variant of {@link #bind(DataFetchingEnvironment, String, ResolvableType)}
+	 * with a pre-extracted raw value to bind from.
+	 * @since 1.3
+	 */
+	@Nullable
+	public Object bind(
+			@Nullable String name, @Nullable Object rawValue, boolean isOmitted, ResolvableType targetType)
+			throws BindException {
+
 		ArgumentsBindingResult bindingResult = new ArgumentsBindingResult(targetType);
 
 		Object value = bindRawValue(

spring-graphql/src/main/java/org/springframework/graphql/data/method/annotation/support/ArgumentMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,8 +23,10 @@
 import org.springframework.graphql.data.GraphQlArgumentBinder;
 import org.springframework.graphql.data.method.HandlerMethodArgumentResolver;
 import org.springframework.graphql.data.method.annotation.Argument;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
+import org.springframework.validation.BindException;
 
 /**
  * Resolver for a method parameter that is annotated with
@@ -58,6 +60,14 @@ public ArgumentMethodArgumentResolver(GraphQlArgumentBinder argumentBinder) {
 	}
 
 
+	/**
+	 * Return the configured {@link GraphQlArgumentBinder}.
+	 * @since 1.3
+	 */
+	public GraphQlArgumentBinder getArgumentBinder() {
+		return this.argumentBinder;
+	}
+
 	@Override
 	public boolean supportsParameter(MethodParameter parameter) {
 		return (parameter.getParameterAnnotation(Argument.class) != null ||
@@ -67,8 +77,19 @@ public boolean supportsParameter(MethodParameter parameter) {
 	@Override
 	public Object resolveArgument(MethodParameter parameter, DataFetchingEnvironment environment) throws Exception {
 		String name = getArgumentName(parameter);
-		ResolvableType resolvableType = ResolvableType.forMethodParameter(parameter);
-		return this.argumentBinder.bind(environment, name, resolvableType);
+		ResolvableType targetType = ResolvableType.forMethodParameter(parameter);
+		return doBind(environment, name, targetType);
+	}
+
+	/**
+	 * Perform the binding with the configured {@link #getArgumentBinder() binder}.
+	 * @since 1.3
+	 */
+	@Nullable
+	protected Object doBind(
+			DataFetchingEnvironment environment, String name, ResolvableType targetType) throws BindException {
+
+		return this.argumentBinder.bind(environment, name, targetType);
 	}
 
 	static String getArgumentName(MethodParameter parameter) {