flatfile

Documentation

Index

• func IsErrFewerThanMinOccurs(err error) bool
• func IsErrUnexpectedData(err error) bool
• type ErrFewerThanMinOccurs
  • func (e ErrFewerThanMinOccurs) Error() string
• type ErrUnexpectedData
  • func (e ErrUnexpectedData) Error() string
• type HierarchyReader
  • func NewHierarchyReader(decls []RecDecl, recReader RecReader, targetXPathExpr *xpath.Expr) *HierarchyReader
  • func (r *HierarchyReader) Read() (*idr.Node, error)
  • func (r *HierarchyReader) Release(n *idr.Node)
• type RecDecl
• type RecReader

Functions

func IsErrFewerThanMinOccurs

func IsErrFewerThanMinOccurs(err error) bool

IsErrFewerThanMinOccurs tells whether a given err is of ErrFewerThanMinOccurs type.

func IsErrUnexpectedData

func IsErrUnexpectedData(err error) bool

IsErrUnexpectedData tells whether a given err is of ErrUnexpectedData type.

Types

type ErrFewerThanMinOccurs

type ErrFewerThanMinOccurs struct {
	RecDecl       RecDecl
	ActualOcccurs int
}

ErrFewerThanMinOccurs indicates the input data doesn't have the required minimum number of instances for a particular record decl.

func (ErrFewerThanMinOccurs) Error

func (e ErrFewerThanMinOccurs) Error() string

Error is to satisfy the error interface. Receivers of this error can/should consider constructing their own file format specific error based on the payload of this error.

type ErrUnexpectedData

type ErrUnexpectedData struct{}

ErrUnexpectedData indicates there is unprocessed and unexpected data from the inpput data stream that no record decl can match.

func (ErrUnexpectedData) Error

func (e ErrUnexpectedData) Error() string

Error is to satisfy the error interface. Receivers of this error can/should consider constructing their own file format specific error based on the payload of this error.

type HierarchyReader

type HierarchyReader struct {
	// contains filtered or unexported fields
}

HierarchyReader orchestrates reading, matching, and converting (to IDR) of data streams of various flat file formats that (potentially) contain hierarchically structured records.

func NewHierarchyReader

func NewHierarchyReader(
	decls []RecDecl, recReader RecReader, targetXPathExpr *xpath.Expr) *HierarchyReader

NewHierarchyReader creates a new instance of a HierarchyReader.

func (*HierarchyReader) Read

func (r *HierarchyReader) Read() (*idr.Node, error)

Read orchestrates reading, matching, and converting (to IDR) of a data stream of a flat file format. Possible return values:

• (node, nil): a target node has been fetched successfully, ready for transformation.
• (nil, io.EOF): no more data to read, all operations completed successfully.
• (nil, ErrFewerThanMinOccurs): a record decl requires a min occurs but isn't satisified by the data stream.
• (nil, ErrUnexpectedData): some unknown/unexpected data encountered that isn't described by any of the record decls.
• (nil, other err): most likely IO failures.

func (*HierarchyReader) Release

func (r *HierarchyReader) Release(n *idr.Node)

Release deallocates/recycles the cached IDR node. If the passed in IDR node happens to be the cached target node, we need to reset/clear the cached target node pointer.

type RecDecl

type RecDecl interface {
	DeclName() string // to avoid collision, since most decl has Name as a field.
	Target() bool
	Group() bool
	MinOccurs() int
	MaxOccurs() int
	ChildDecls() []RecDecl
}

RecDecl defines a flat file record. It is meant to be a common facade for all the actual unit of processing from each format, such as envelope from fixed length, segment from EDI, and record from csv, etc.

type RecReader

type RecReader interface {
	// MoreUnprocessedData indicates whether there is any unprocessed data left in the input
	// stream. Possible return values:
	// - (true, nil): more data is available.
	// - (false, nil): no more data is available.
	// - (_, err): some and most likely fatal IO error has occurred.
	// Implementation notes:
	// - If some data is read in and io.EOF is encountered, (true, nil) should be returned.
	// - If no data is read in and io.EOF is encountered, (false, nil) should be returned.
	// - Under no circumstances, io.EOF should be returned.
	// - Once a call to this method returns (false, nil), all future calls to it should always
	//   return (false, nil).
	MoreUnprocessedData() (more bool, err error)

	// ReadAndMatch matches the passed-in *non-group* RecDecl to unprocessed data and creates a
	// corresponding IDR node if data matches and createIDR flag is turned on.
	// Implementation notes:
	// - If io.EOF is encountered while there is still unmatched thus unprocessed data,
	//   io.EOF shouldn't be returned.
	// - If a non io.EOF error encountered during IO, return (false, nil, err).
	ReadAndMatch(decl RecDecl, createIDR bool) (matched bool, node *idr.Node, err error)
}

RecReader defines an interface for a flat file specific format to read data and match a RecDecl.