infovis.metadata
Class ValueCategory

java.lang.Object
  infovis.metadata.ValueCategory

All Implemented Interfaces:

Constants

Direct Known Subclasses:

ColorVisualizationFactory

public abstract class ValueCategory
extends Object
implements Constants

Qualify what the column values expresses.

A Column can contain values of five categories:

1. Ordered: there is a natural ordering among the value, like integers
2. Nominal: all the values are labels.
3. Categorical: values are category names.
4. Differential: there is a nominal value and the values are compared to it, like percentage of votes around 50%.
5. Explicit: values are color encoded as ALPHA,RED,GREEN,BLUE

The representation of value should take the category into account. For example, coloring should be different: ordered values are usually depicted with intensity, nominal and categorical value with different hues, differential may use black for the the nominal value and to two other colors for above and below.

Controls for dynamic queries should also take the category into account. Range Sliders can be used with ordered value, differential and nominal values if that makes sense (an order can usually be derived from a nominal value, like lexicographical order, but this is somewhat artificial). For categorical value, radio shapes or other buttons can be used.

When nothing is known about a column, we assign it a category depending on its type.

Version:

$Revision: 1.7 $

Author:

Jean-Daniel Fekete

Field Summary

static String[]	CATEGORY_NAME String names of integer categories.
static int	TYPE_CATEGORIAL integer constant for categorical type.
static int	TYPE_DIFFERENTIAL integer constant for differential type.
static int	TYPE_EXPLICIT integer constant for explicit type.
static int	TYPE_NOMINAL integer constant for nominal type.
static int	TYPE_ORDERED integer constant for ordered type.
static int	TYPE_UNKOWN integer constant for unkown type.
static String	VALUE_CATEGORY_TYPE Key for the metadata.
static String	VALUE_CATEGORY_TYPE_CATEGORICAL Values are categorical.
static String	VALUE_CATEGORY_TYPE_DIFFERENTIAL Values are differential (for example, around 0).
static String	VALUE_CATEGORY_TYPE_DIFFERENTIAL_REFERENCE When the VALUE_TYPE is differential, the reference value can be stored as the value of this metadata property.
static String	VALUE_CATEGORY_TYPE_EXPLICIT Values are explicit color values.
static String	VALUE_CATEGORY_TYPE_NOMINAL Value are nominal.
static String	VALUE_CATEGORY_TYPE_ORDERED Values are ordered.

Fields inherited from interface infovis.metadata.Constants

CONTRIBUTOR, COVERAGE, CREATOR, DATE, DESCRITION, FORMAT, IDENTIFIER, LANGUAGE, PUBLISHER, RELATION, RIGHTS, SOURCE, SUBJECT, TITLE, TYPE

Constructor Summary

ValueCategory()

Method Summary

static String	categoryName(int cat) Returns the category name of a specified category.
static int	categoryValue(String catString) Returns a value category given its category name.
static int	findValueCategory(Column c) Returns a category constant associated with the specified column, guessing one is none is associated with the column.
static int	getValueCategory(Column c) Returns the category constant associated with the specified column.
static String	getValueCategoryString(Column c) Returns the category string associated with the specified column or null.
static void	setValueCategory(Column c, int cat) Associates a value category to a column.

Methods inherited from class java.lang.Object

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

Field Detail

VALUE_CATEGORY_TYPE

public static final String VALUE_CATEGORY_TYPE

Key for the metadata.

See Also:

Constant Field Values

VALUE_CATEGORY_TYPE_ORDERED

public static final String VALUE_CATEGORY_TYPE_ORDERED

Values are ordered.

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Constant Field Values

VALUE_CATEGORY_TYPE_NOMINAL

public static final String VALUE_CATEGORY_TYPE_NOMINAL

Value are nominal.

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Constant Field Values

VALUE_CATEGORY_TYPE_CATEGORICAL

public static final String VALUE_CATEGORY_TYPE_CATEGORICAL

Values are categorical.

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Constant Field Values

VALUE_CATEGORY_TYPE_DIFFERENTIAL

public static final String VALUE_CATEGORY_TYPE_DIFFERENTIAL

Values are differential (for example, around 0).

See Also:

Constant Field Values

VALUE_CATEGORY_TYPE_EXPLICIT

public static final String VALUE_CATEGORY_TYPE_EXPLICIT

Values are explicit color values.

See Also:

Constant Field Values

TYPE_UNKOWN

public static final int TYPE_UNKOWN

integer constant for unkown type.

See Also:

Constant Field Values

TYPE_ORDERED

public static final int TYPE_ORDERED

integer constant for ordered type.

See Also:

Constant Field Values

TYPE_NOMINAL

public static final int TYPE_NOMINAL

integer constant for nominal type.

See Also:

Constant Field Values

TYPE_CATEGORIAL

public static final int TYPE_CATEGORIAL

integer constant for categorical type.

See Also:

Constant Field Values

TYPE_DIFFERENTIAL

public static final int TYPE_DIFFERENTIAL

integer constant for differential type.

See Also:

Constant Field Values

TYPE_EXPLICIT

public static final int TYPE_EXPLICIT

integer constant for explicit type.

See Also:

Constant Field Values

CATEGORY_NAME

public static final String[] CATEGORY_NAME

String names of integer categories.

VALUE_CATEGORY_TYPE_DIFFERENTIAL_REFERENCE

public static final String VALUE_CATEGORY_TYPE_DIFFERENTIAL_REFERENCE

When the VALUE_TYPE is differential, the reference value can be stored as the value of this metadata property.

See Also:

Constant Field Values

Constructor Detail

ValueCategory

public ValueCategory()

Method Detail

getValueCategoryString

public static String getValueCategoryString(Column c)

Returns the category string associated with the specified column or null.

Parameters:

c - the column,

Returns:

the category string associated with the specified column or null if no category is associated with it.

getValueCategory

public static int getValueCategory(Column c)

Returns the category constant associated with the specified column.

Parameters:

c - the column.

Returns:

the category constant associated with the specified column or TYPE_UNKNOWN if no category is associated with it.

setValueCategory

public static void setValueCategory(Column c,
                                    int cat)

Associates a value category to a column.

Parameters:

c - the column

cat - the category

findValueCategory

public static int findValueCategory(Column c)

Returns a category constant associated with the specified column, guessing one is none is associated with the column.

Parameters:

c - the column

Returns:

a category constant associated with the specified column, guessing one is none is associated with the column.

categoryName

public static String categoryName(int cat)

Returns the category name of a specified category.

Parameters:

cat - the category

Returns:

the category name of a specified category

categoryValue

public static int categoryValue(String catString)

Returns a value category given its category name.

Parameters:

catString - the category name

Returns:

a value category given its category name.