com.conveyal.gtfs.graphql.fetchers

Class SQLColumnFetcher<T>

java.lang.Object

com.conveyal.gtfs.graphql.fetchers.SQLColumnFetcher<T>

All Implemented Interfaces:

graphql.schema.DataFetcher<List<T>>

public class SQLColumnFetcher<T>
extends Object
implements graphql.schema.DataFetcher<List<T>>

This wraps an SQL row fetcher, extracting only a single column of the specified type. Because there's only one column, it collapses the result down into a list of elements of that column's type, rather than a list of maps (one for each row) as the basic SQL fetcher does.

Field Summary

Fields

Modifier and Type	Field and Description
String	columnName
static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Constructor and Description
SQLColumnFetcher(String tableName, String parentJoinField, String columnName) Constructor for tables that don't need any restriction by a where clause based on the enclosing entity.

Method Summary

Modifier and Type	Method and Description
List<T>	get(graphql.schema.DataFetchingEnvironment environment)

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

columnName

public final String columnName

Constructor Detail

SQLColumnFetcher

public SQLColumnFetcher(String tableName,
                        String parentJoinField,
                        String columnName)

Constructor for tables that don't need any restriction by a where clause based on the enclosing entity. These would typically be at the topmost level, directly inside a feed rather than nested in some GTFS entity type.

Method Detail

get

public List<T> get(graphql.schema.DataFetchingEnvironment environment)

Specified by:

get in interface graphql.schema.DataFetcher<List<T>>