com.conveyal.gtfs.graphql.fetchers

Class NestedJDBCFetcher

java.lang.Object

com.conveyal.gtfs.graphql.fetchers.NestedJDBCFetcher

All Implemented Interfaces:

graphql.schema.DataFetcher<List<Map<String,Object>>>

public class NestedJDBCFetcher
extends Object
implements graphql.schema.DataFetcher<List<Map<String,Object>>>

This fetcher uses nested calls to the general JDBCFetcher for SQL data. It uses the parent entity and a series of joins to leap frog from one entity to another more distantly-related entity. For example, if we want to know the routes that serve a specific stop, starting with a top-level stop type, we can nest joins from stop ABC -> pattern stops -> patterns -> routes (see below example implementation for more details).

Constructor Summary

Constructors

Constructor and Description
NestedJDBCFetcher(JDBCFetcher... jdbcFetchers) Constructor for data that must be derived by chaining multiple joins together.

Method Summary

Modifier and Type	Method and Description
static graphql.schema.GraphQLFieldDefinition	field(String tableName)
List<Map<String,Object>>	get(graphql.schema.DataFetchingEnvironment environment)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NestedJDBCFetcher

public NestedJDBCFetcher(JDBCFetcher... jdbcFetchers)

Constructor for data that must be derived by chaining multiple joins together.

Method Detail

field

public static graphql.schema.GraphQLFieldDefinition field(String tableName)

get

public List<Map<String,Object>> get(graphql.schema.DataFetchingEnvironment environment)

Specified by:

get in interface graphql.schema.DataFetcher<List<Map<String,Object>>>