uk.ac.starlink.table.formats

Class RowEvaluator

java.lang.Object

uk.ac.starlink.table.formats.RowEvaluator

public class RowEvaluator
extends Object

Examines unknown rows (arrays of strings) to work out what they contain. By repeatedly calling submitRow(java.util.List<java.lang.String>) the evaluator can refine its idea of what kind of data is represented by each column.

Since:

21 Sep 2004

Author:

Mark Taylor (Starlink)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RowEvaluator.Decoder<T> Interface for an object that can turn a string into a cell content object.
static class	RowEvaluator.Metadata Helper class used to group quantities which describe what the data types found in the columns of a table are.

Field Summary

Fields

Modifier and Type	Field and Description
static RowEvaluator.Decoder<Void>	BLANK_DECODER Decoder for values that are all blank.
static RowEvaluator.Decoder<Boolean>	BOOLEAN_DECODER Decoder for booleans.
static RowEvaluator.Decoder<String>	DATE_DECODER Decoder for ISO-8601 dates.
static RowEvaluator.Decoder<String>	DMS_DECODER Decoder for DMS sexagesimal strings.
static RowEvaluator.Decoder<Double>	DOUBLE_DECODER Decoder for doubles.
static RowEvaluator.Decoder<Float>	FLOAT_DECODER Decoder for floats.
static RowEvaluator.Decoder<String>	HMS_DECODER Decoder for HMS sexagesimal strings.
static RowEvaluator.Decoder<Integer>	INTEGER_DECODER Decoder for integers.
static Pattern	ISO8601_REGEX Regular expression for ISO 8601 dates.
static RowEvaluator.Decoder<Long>	LONG_DECODER Decoder for longs.
static RowEvaluator.Decoder<Short>	SHORT_DECODER Decoder for shorts.
static RowEvaluator.Decoder<String>	STRING_DECODER Decoder for any old string.

Constructor Summary

Constructors

Constructor and Description
RowEvaluator() Constructs a new RowEvaluator which will work out the number of columns from the data using the standard list of decoders.
RowEvaluator(int ncol) Constructs a new RowEvaluator which will examine rows with a fixed number of columns using the standard list of decoders.
RowEvaluator(RowEvaluator.Decoder<?>[] decoders) Constructs a new RowEvaluator which will work out the number of columns from the data using a supplied list of decoders.

Method Summary

Modifier and Type	Method and Description
RowEvaluator.Metadata	getMetadata() Returns information gleaned from previous submitRow calls about the kind of data that appears to be in the columns.
static RowEvaluator.Decoder<?>[]	getStandardDecoders() Returns the standard list of decoder implementation used for identifying column types.
void	submitRow(List<String> row) Looks at a given row (list of strings) and records information about what sort of things it looks like it contains.

Methods inherited from class java.lang.Object

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

Field Detail

ISO8601_REGEX

public static final Pattern ISO8601_REGEX

Regular expression for ISO 8601 dates.

BLANK_DECODER

public static final RowEvaluator.Decoder<Void> BLANK_DECODER

Decoder for values that are all blank.

BOOLEAN_DECODER

public static final RowEvaluator.Decoder<Boolean> BOOLEAN_DECODER

Decoder for booleans.

SHORT_DECODER

public static final RowEvaluator.Decoder<Short> SHORT_DECODER

Decoder for shorts.

INTEGER_DECODER

public static final RowEvaluator.Decoder<Integer> INTEGER_DECODER

Decoder for integers.

LONG_DECODER

public static final RowEvaluator.Decoder<Long> LONG_DECODER

Decoder for longs.

FLOAT_DECODER

public static final RowEvaluator.Decoder<Float> FLOAT_DECODER

Decoder for floats.

DOUBLE_DECODER

public static final RowEvaluator.Decoder<Double> DOUBLE_DECODER

Decoder for doubles.

DATE_DECODER

public static final RowEvaluator.Decoder<String> DATE_DECODER

Decoder for ISO-8601 dates.

HMS_DECODER

public static final RowEvaluator.Decoder<String> HMS_DECODER

Decoder for HMS sexagesimal strings.

DMS_DECODER

public static final RowEvaluator.Decoder<String> DMS_DECODER

Decoder for DMS sexagesimal strings.

STRING_DECODER

public static final RowEvaluator.Decoder<String> STRING_DECODER

Decoder for any old string.

Constructor Detail

RowEvaluator

public RowEvaluator()

Constructs a new RowEvaluator which will work out the number of columns from the data using the standard list of decoders.

RowEvaluator

public RowEvaluator(RowEvaluator.Decoder<?>[] decoders)

Constructs a new RowEvaluator which will work out the number of columns from the data using a supplied list of decoders.

Note the order of the supplied decoder list is significant; a type earlier in the list will be preferred over one later in the list where the data is consistent with both.

In case of no match, a string decoder will be used, even if it does not appear in the supplied list.

Parameters:

decoders - list of allowed decoders

RowEvaluator

public RowEvaluator(int ncol)

Constructs a new RowEvaluator which will examine rows with a fixed number of columns using the standard list of decoders.

Parameters:

ncol - column count

Method Detail

submitRow

public void submitRow(List<String> row)
               throws TableFormatException

Looks at a given row (list of strings) and records information about what sort of things it looks like it contains.

Parameters:

row - ncol-element list of strings

Throws:

TableFormatException - if the number of elements in row is not the same as on the first call

getMetadata

public RowEvaluator.Metadata getMetadata()

Returns information gleaned from previous submitRow calls about the kind of data that appears to be in the columns.

Returns:

metadata

getStandardDecoders

public static RowEvaluator.Decoder<?>[] getStandardDecoders()

Returns the standard list of decoder implementation used for identifying column types.

Returns:

standard decoder list