graphql.kickstart.tools.relay.RelayConnectionFactory.kt Maven / Gradle / Ivy
package graphql.kickstart.tools.relay
import graphql.kickstart.tools.TypeDefinitionFactory
import graphql.language.*
class RelayConnectionFactory : TypeDefinitionFactory {
override fun create(existing: MutableList>): List> {
val definitions = mutableListOf>()
val definitionsByName = existing.filterIsInstance>()
.associateBy { it.name }
.toMutableMap()
findConnectionDirectives(existing)
.flatMap { createDefinitions(it) }
.forEach {
if (!definitionsByName.containsKey(it.name)) {
definitionsByName[it.name] = it
definitions.add(it)
}
}
if (!definitionsByName.containsKey("PageInfo")) {
definitions.add(createPageInfo())
}
return definitions
}
private fun findConnectionDirectives(definitions: List>): List {
return definitions.filterIsInstance()
.flatMap { it.fieldDefinitions }
.flatMap { it.directivesWithField() }
.filter { it.name == "connection" }
}
private fun createDefinitions(directive: DirectiveWithField): List {
val definitions = mutableListOf()
definitions.add(createConnectionDefinition(directive.getTypeName()))
definitions.add(createEdgeDefinition(directive.getTypeName(), directive.forTypeName()))
return definitions.toList()
}
private fun createConnectionDefinition(type: String): ObjectTypeDefinition =
ObjectTypeDefinition.newObjectTypeDefinition()
.name(type)
.fieldDefinition(FieldDefinition("edges", ListType(TypeName(type + "Edge"))))
.fieldDefinition(FieldDefinition("pageInfo", TypeName("PageInfo")))
.build()
private fun createEdgeDefinition(connectionType: String, nodeType: String): ObjectTypeDefinition =
ObjectTypeDefinition.newObjectTypeDefinition()
.name(connectionType + "Edge")
.fieldDefinition(FieldDefinition("cursor", TypeName("String")))
.fieldDefinition(FieldDefinition("node", TypeName(nodeType)))
.build()
private fun createPageInfo(): ObjectTypeDefinition =
ObjectTypeDefinition.newObjectTypeDefinition()
.name("PageInfo")
.fieldDefinition(FieldDefinition("hasPreviousPage", NonNullType(TypeName("Boolean"))))
.fieldDefinition(FieldDefinition("hasNextPage", NonNullType(TypeName("Boolean"))))
.fieldDefinition(FieldDefinition("startCursor", TypeName("String")))
.fieldDefinition(FieldDefinition("endCursor", TypeName("String")))
.build()
private fun Directive.forTypeName(): String {
return (this.getArgument("for").value as StringValue).value
}
private fun Directive.withField(field: FieldDefinition): DirectiveWithField {
return DirectiveWithField(field, this.name, this.arguments, this.sourceLocation, this.comments)
}
private fun FieldDefinition.directivesWithField(): List {
return this.directives.map { it.withField(this) }
}
class DirectiveWithField(val field: FieldDefinition, name: String, arguments: List, sourceLocation: SourceLocation, comments: List) : Directive(name, arguments, sourceLocation, comments, IgnoredChars.EMPTY, emptyMap()) {
fun getTypeName(): String {
val type = field.type
if (type is NonNullType) {
return (type.type as TypeName).name
}
return (field.type as TypeName).name
}
}
}