Help in implementing data fetcher for a federated subgraph

[shamin2021]

I have the following two schemas
Schema 1
type Query {
getFoo: Foo
}

type Foo @key(fields: "id"){
id: String
fooName: String
}

Schema 2
type Query {
getBar(barId: String): Bar
}

type Bar @key(fields: "id") {
id: String
barName: String
}

type Foo @extends @key(fields: "id") {
id: String @external
bar: Bar
}

and the service providers as

Bar

package org.example;

class ProductNameService implements ServiceProvider {

String filePath1 = "src/main/resources/Product.graphql";

public String schema;
{
    try {
        schema = readFileAsString(filePath1);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}


@Override
public String getNameSpace() { return "PERSON_NAME"; }

@Override
public ServiceType getSeviceType() {
    return ServiceType.FEDERATION_SUBGRAPH;
}

@Override
public Map<String, String> sdlFiles() { return ImmutableMap.of("schema.graphqls", schema); }

@Override
public CompletableFuture<Map<String, Object>> query(final ExecutionInput executionInput,
                                                    final GraphQLContext context) {
    return null;
}

public static String readFileAsString(String filePath) throws Exception {
    Path path = Paths.get(filePath);
    byte[] bytes = Files.readAllBytes(path);
    String content = new String(bytes, StandardCharsets.UTF_8);
    return content;
}

}

and

Food service
package org.example;

import com.google.common.collect.ImmutableMap;
import com.intuit.graphql.orchestrator.ServiceProvider;
import graphql.ExecutionInput;
import graphql.GraphQLContext;

import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.*;
import java.util.concurrent.CompletableFuture;

class ProductReviewService implements ServiceProvider {

String filePath1 = "src/main/resources/Reviews.graphql";
String filePath2 = "src/main/resources/resolverSchema.graphql";

public  final String schema;
public  final String resolverSchema;

{
    try {
        schema = readFileAsString(filePath1);
        resolverSchema = readFileAsString(filePath2);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}


@Override
public String getNameSpace() { return "PERSON_ADDRESS";}

@Override
public Map<String, String> sdlFiles() { return ImmutableMap.of("schema.graphqls", schema, "resolver.graphqls", resolverSchema);}

@Override
public ServiceType getSeviceType() {
    return ServiceType.FEDERATION_SUBGRAPH;
}

@Override
public CompletableFuture<Map<String, Object>> query (final ExecutionInput executionInput, final GraphQLContext context) {
    return null;

}

public static String readFileAsString(String filePath) throws Exception {
    Path path = Paths.get(filePath);
    byte[] bytes = Files.readAllBytes(path);
    String content = new String(bytes, StandardCharsets.UTF_8);
    return content;
}

}

i have the main class as

package org.example;
public class Test {

public static void main(String[] args) throws Exception {

    // create a runtimeGraph by stitching service providers
    RuntimeGraph runtimeGraph = SchemaStitcher.newBuilder()
            .service(new ProductNameService())
            .service(new ProductReviewService())
            .build()
            .stitchGraph();

    String schema = new SchemaPrinter().print(runtimeGraph.getExecutableSchema());


    // pass the runtime graph to GraphQLOrchestrator
    GraphQLOrchestrator graphQLOrchestrator = GraphQLOrchestrator.newOrchestrator()
            .runtimeGraph(runtimeGraph).build();

    // Print SDL of supergraph
    String grastrator = new SchemaPrinter().print(graphQLOrchestrator.getSchema());
    System.out.println(grastrator);

    //Execute the query
    CompletableFuture<ExecutionResult> execute = graphQLOrchestrator
            .execute(
                    ExecutionInput.newExecutionInput()
                            .query( "query { getBar (barId: \"1\"){id} }")
                            .build()
            );

    //get execution result and print
    ExecutionResult executionResult = execute.get();
    System.out.println("--------------------------------------");
    System.out.println(executionResult);
}

}

but when executed i get the following error please hep me resolve this
ExecutionResultImpl{errors=[ExceptionWhileDataFetching{path=[getBar], exception=java.lang.IllegalAccessError: class com.intuit.graphql.orchestrator.common.ArgumentValueResolver tried to access private method 'void graphql.execution.ValuesResolver.()' (com.intuit.graphql.orchestrator.common.ArgumentValueResolver and graphql.execution.ValuesResolver are in unnamed module of loader 'app'), locations=[SourceLocation{line=1, column=9}]}], data={getBar=null}, dataPresent=true, extensions=null}

[ashpak-shaikh]

you have to implement the query method in both the product name and review service and that needs to return the data against the query. When you execute the query against the orchestrator, it will make queries against the service provider. Can u post an example of this in a git repo so I can take a look at it?

Also, you can try the gateway locally that has sample subgraphs in the local registry folder.

https://github.com/graph-quilt/graphql-gateway-java

[shamin2021]

https://github.com/shamin2021/graphql-java.git
this is the git repo with the code in the [Graphql-schemaregistry] branch

I am new to graphql it would be great if you could give me some pointers therefore
thankyou very much