com.luciad.ogc.filter.model

LuciadLightspeedClass TLcdOGCFunction

java.lang.Object

com.luciad.datamodel.TLcdDataObject

com.luciad.ogc.filter.model.TLcdOGCFunction

All Implemented Interfaces:

ILcdDataObject, ILcdGenericExpression, ILcdOGCCondition, ILcdOGCExpression, ILcdCloneable, ILcdDeepCloneable, Cloneable

public class TLcdOGCFunction
extends TLcdDataObject
implements ILcdOGCExpression, ILcdOGCCondition

This class represents the <ogc:Function> element.

According to the OGC Filter specification, a function is a named procedure that performs a distinct computation. A function may accept zero or more arguments as input and generates a single result.

You can use a function as an ILcdOGCCondition if it evaluates to a boolean result value (null corresponds to false). This is equivalent to:

   eq(function(FUNCTION_NAME, ...), literal(true))
 

If you use a function as condition, but it evaluates to anything else, you will get errors while evaluating.

A TLcdOGCFunction instance is composed of the name of the function, and zero or more arguments that can be any instances of ILcdOGCExpression.

When you create OGC filters containing a custom function, you must make sure the ILcdOGCFilterEvaluator used to evaluate the OGC filter can handle this custom function. For the default evaluator (TLcdOGCFilterEvaluator), this is achieved by calling TLcdOGCFilterEvaluator.registerFunction(TLcdXMLName, ILcdEvaluatorFunction) for each custom function.

A set of predefined vendor-specific functions are available out-of-the-box: see TLcdOGCVendorSpecificFunctions.

See Also:

ILcdOGCExpression, TLcdOGCVendorSpecificFunctions

Constructor Summary

Constructors

Constructor and Description
TLcdOGCFunction() Default constructor.
TLcdOGCFunction(String aName) Constructs an instance with a given function name.

Method Summary

Modifier and Type	Method and Description
void	addArgument(ILcdOGCExpression aExpression) Adds an argument to the argument list of the function.
boolean	equals(Object obj)
ILcdOGCExpression	getArgument(int aIndex) Gets the argument of the function at a given position.
int	getArgumentCount() Gets the count of arguments of the function.
List<ILcdOGCExpression>	getArguments() Returns the list of arguments for this function.
String	getName() Gets the name of the function.
int	hashCode()
void	insertArgumentAt(ILcdOGCExpression aExpression, int aIndex) Inserts an argument to the argument list of the function at a given position.
boolean	removeArgument(ILcdOGCExpression aExpression) Removes a given argument from the argument list of the function.
void	setName(String aName) Sets the name of the function.
String	toString()

Methods inherited from class com.luciad.datamodel.TLcdDataObject

clone, clone, getDataType, getValue, getValue, hasValue, hasValue, setValue, setValue

Methods inherited from class java.lang.Object

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

Constructor Detail

TLcdOGCFunction

public TLcdOGCFunction()

Default constructor.

TLcdOGCFunction

public TLcdOGCFunction(String aName)

Constructs an instance with a given function name.

Parameters:

aName - the name of the function

Method Detail

getName

public String getName()

Gets the name of the function.

Returns:

the name of the function.

setName

public void setName(String aName)

Sets the name of the function.

Parameters:

aName - the name of the function.

removeArgument

public boolean removeArgument(ILcdOGCExpression aExpression)

Removes a given argument from the argument list of the function.

Parameters:

aExpression - the argument to be removed from the argument list of the function.

Returns:

true if aExpression was an argument of the function; false otherwise.

getArguments

public List<ILcdOGCExpression> getArguments()

Returns the list of arguments for this function.

Returns:

the list of arguments

insertArgumentAt

public void insertArgumentAt(ILcdOGCExpression aExpression,
                             int aIndex)

Inserts an argument to the argument list of the function at a given position.

Parameters:

aExpression - the argument to be inserted.

aIndex - the index of the given position.

addArgument

public void addArgument(ILcdOGCExpression aExpression)

Adds an argument to the argument list of the function.

Parameters:

aExpression - the argument to be added.

getArgumentCount

public int getArgumentCount()

Gets the count of arguments of the function.

Returns:

the count of arguments of the function.

getArgument

public ILcdOGCExpression getArgument(int aIndex)

Gets the argument of the function at a given position.

Parameters:

aIndex - the index of the given position.

Returns:

the argument at a given position.

toString

public String toString()

Overrides:

toString in class TLcdDataObject

Returns:

a String version of the function's name and its arguments.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object