net.sf.farrago.namespace.flatfile
Class FlatFileProgramWriter

java.lang.Object
  net.sf.farrago.namespace.flatfile.FlatFileProgramWriter

public class FlatFileProgramWriter
extends Object

FlatFileProgramWriter builds calculator programs for converting text from flat files into typed data. It assumes the text has already been processed for quoting and escape characters. The programs mainly consist of simple casts. However, custom date formats may be specified when using LucidDb. They are implemented with calls to LucidDb user defined routines. Only one set of formats can be active for a writer.

When using custom date conversions, the program can be split into Fennel and Java-only sections. If splitting the program, data must flow through the Fennel section first, which handles basic casts. Then the Java-only section handles custom date conversions.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/namespace/flatfile/FlatFileProgramWriter.java#2 $

Author:

jpham

Nested Class Summary

private static class

FlatFileProgramWriter.Section Identifies a section of a flat file program

Field Summary

private String	dateFormat
private static int	DATETIME_FORMAT_ARG_LENGTH
private RelDataType[]	datetimeArgs
static int	FLAT_FILE_MAX_NON_CHAR_VALUE_LEN
private RexBuilder	rexBuilder
private RelDataType	rowType
private FarragoPreparingStmt	stmt
private String	timeFormat
private String	timestampFormat
private static SqlIdentifier	toDateFuncName
private static SqlIdentifier	toTimeFuncName
private static SqlIdentifier	toTimestampFuncName
private RelDataTypeFactory	typeFactory

Constructor Summary

FlatFileProgramWriter(RexBuilder rexBuilder, FarragoPreparingStmt stmt, FlatFileParams params, RelDataType rowType)
Constructs a new FlatFileProgramWriter

Method Summary

RexProgram	getFennelSection() Gets the Fennel portion of the data conversion program
private String	getFormat(RelDataType type) Returns the custom format for a data type
RexProgram	getJavaOnlySection() Gets the Java only portion of the data conversion program
RexProgram	getProgram() Gets the entire data conversion program
private RexProgram	getSection(FlatFileProgramWriter.Section section) Builds a section of the data conversion program as follows.
private RelDataType	getTextType(RelDataType sqlType) Converts a SQL type into a type that can be used by a Fennel FlatFileExecStream to read files.
private SqlFunction	getUdr(RelDataType type, RelDataType charType) Gets a function that converts a string to another type, according to a format string.
private boolean	isCustom(RelDataType type) Whether a data type has a custom format

Methods inherited from class java.lang.Object

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

Field Detail

FLAT_FILE_MAX_NON_CHAR_VALUE_LEN

public static final int FLAT_FILE_MAX_NON_CHAR_VALUE_LEN

See Also:

Constant Field Values

toDateFuncName

private static final SqlIdentifier toDateFuncName

toTimeFuncName

private static final SqlIdentifier toTimeFuncName

toTimestampFuncName

private static final SqlIdentifier toTimestampFuncName

DATETIME_FORMAT_ARG_LENGTH

private static final int DATETIME_FORMAT_ARG_LENGTH

See Also:

Constant Field Values

rexBuilder

private final RexBuilder rexBuilder

typeFactory

private final RelDataTypeFactory typeFactory

stmt

private final FarragoPreparingStmt stmt

dateFormat

private final String dateFormat

timeFormat

private final String timeFormat

timestampFormat

private final String timestampFormat

datetimeArgs

private final RelDataType[] datetimeArgs

rowType

private final RelDataType rowType

Constructor Detail

FlatFileProgramWriter

public FlatFileProgramWriter(RexBuilder rexBuilder,
                             FarragoPreparingStmt stmt,
                             FlatFileParams params,
                             RelDataType rowType)

Constructs a new FlatFileProgramWriter

Parameters:

rexBuilder - a rex node builder

stmt - the statement being prepared

params - a set of flat file server parameters. These parameters may include custom date formats

rowType - the desired data type for data read from a flat file. The row type is also used to infer the size of text fields in the file.

Method Detail

getProgram

public RexProgram getProgram()

Gets the entire data conversion program

getFennelSection

public RexProgram getFennelSection()

Gets the Fennel portion of the data conversion program

getJavaOnlySection

public RexProgram getJavaOnlySection()

Gets the Java only portion of the data conversion program

Returns:

the program, or null if it is empty

getSection

private RexProgram getSection(FlatFileProgramWriter.Section section)

Builds a section of the data conversion program as follows.

• FENNEL: all inputs are text columns. Most inputs are casted to target types, except custom date fields, which are projected
• JAVA_ONLY: most inputs are typed data, except custom date fields, which are text columns. The typed fields are projected, while the date fields are converted with user defined routines.
• ALL: all inputs are text columns and all are converted to target types, either by casting or by UDRs.

Parameters:

section - section of the program to build

Returns:

the program section

getTextType

private RelDataType getTextType(RelDataType sqlType)

Converts a SQL type into a type that can be used by a Fennel FlatFileExecStream to read files.

isCustom

private boolean isCustom(RelDataType type)

Whether a data type has a custom format

getFormat

private String getFormat(RelDataType type)

Returns the custom format for a data type

getUdr

private SqlFunction getUdr(RelDataType type,
                           RelDataType charType)

Gets a function that converts a string to another type, according to a format string. Throws an exception if the function was not found.

Parameters:

type - the target type

charType - the type of the string

Returns:

a matching conversion function