org.geotools.mbstyle.expression

Class MBExpression

Object

ExpressionAbstract

FunctionImpl

MBExpression

All Implemented Interfaces:

Expression, Function

Direct Known Subclasses:

MBColor, MBDecision, MBFeatureData, MBHeatmap, MBLookup, MBMath, MBRampsScalesCurves, MBString, MBTypes, MBVariableBinding, MBZoom

public abstract class MBExpression
extends FunctionImpl

The value for any layout property, paint property, or filter may be specified as an expression. An expression defines a formula for computing the value of the property using the operators described below: -Mathematical operators for performing arithmetic and other operations on numeric values -Logical operators for manipulating boolean values and making conditional decisions -String operators for manipulating strings -Data operators, providing access to the properties of source features -Camera operators, providing access to the parameters defining the current map view

Expressions are represented as JSON arrays. The first element of an expression array is a string naming the expression operator, e.g. "*"or "case". Subsequent elements (if any) are the arguments to the expression. Each argument is either a literal value (a string, number, boolean, or null), or another expression array.

Field Summary

Fields

Modifier and Type	Field and Description
static List<String>	colors
static List<String>	decisions
static List	featureData
protected FilterFactory2	ff
static List	heatMap
protected JSONArray	json
static List	lookUp
static List	math
protected String	name
protected MBObjectParser	parse
static List	ramps
static List	string
protected MBStyleTransformer	transformer
static List	types
static List	variableBindings
static List	zoom

Fields inherited from class FunctionImpl

functionName

Fields inherited from interface Expression

NIL

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MBExpression(JSONArray json) Please use factory method create(JSONArray)

Method Summary

Modifier and Type	Method and Description
static boolean	canCreate(String name)
static MBExpression	create(JSONArray json) Factory method used to produce the correct MBExpression subclass for the provided JSONArray.
abstract Expression	getExpression() Determines which expression to use.
String	getName() Gets the name of this function.
protected void	throwInsufficientArgumentCount(String expression, int argCount)
protected void	throwUnexpectedArgumentCount(String expression, int argCount)
static Expression	transformExpression(JSONArray json) Creates an MBExpression and calls the associated function.
Expression	transformLiteral(Expression ex) A function to evaluate a given parameter as an expression and use the MBStyleTransformer to transform Mapbox tokens into CQL expressions.

Methods inherited from class FunctionImpl

accept, dispatchArguments, equals, evaluate, functionName, getFallbackValue, getFunctionName, getParameters, getParameterValue, getParameterValue, hashCode, setFallbackValue, setName, setParameters, toString

Methods inherited from class ExpressionAbstract

evaluate

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface Expression

evaluate

Field Detail

json

protected final JSONArray json

name

protected final String name

ff

protected final FilterFactory2 ff

parse

protected final MBObjectParser parse

transformer

protected final MBStyleTransformer transformer

colors

public static final List<String> colors

decisions

public static final List<String> decisions

featureData

public static final List featureData

heatMap

public static final List heatMap

lookUp

public static final List lookUp

math

public static final List math

ramps

public static final List ramps

string

public static final List string

types

public static final List types

variableBindings

public static final List variableBindings

zoom

public static final List zoom

Constructor Detail

MBExpression

protected MBExpression(JSONArray json)

Please use factory method create(JSONArray)

Parameters:

json - definition

Method Detail

getName

public String getName()

Description copied from class: FunctionImpl

Gets the name of this function.

Specified by:

getName in interface Function

Overrides:

getName in class FunctionImpl

Returns:

the name of the function.

create

public static MBExpression create(JSONArray json)

Factory method used to produce the correct MBExpression subclass for the provided JSONArray.

Parameters:

json - definition

Returns:

MBExpression

canCreate

public static boolean canCreate(String name)

getExpression

public abstract Expression getExpression()

Determines which expression to use.

transformLiteral

public Expression transformLiteral(Expression ex)

A function to evaluate a given parameter as an expression and use the MBStyleTransformer to transform Mapbox tokens into CQL expressions.

Returns:

cq; text expression

transformExpression

public static Expression transformExpression(JSONArray json)

Creates an MBExpression and calls the associated function.

throwUnexpectedArgumentCount

protected void throwUnexpectedArgumentCount(String expression,
                                            int argCount)
                                     throws MBFormatException

Throws:

MBFormatException

throwInsufficientArgumentCount

protected void throwInsufficientArgumentCount(String expression,
                                              int argCount)
                                       throws MBFormatException

Throws:

MBFormatException