prefuse.data.expression
Class FunctionExpression

java.lang.Object
  prefuse.data.expression.AbstractExpression
      prefuse.data.expression.FunctionExpression

All Implemented Interfaces:

java.util.EventListener, ExpressionListener, Expression, Function

public abstract class FunctionExpression
extends AbstractExpression
implements Function

Abstract base class for FunctionExpression implementations. Provides parameter handling support.

Author:

jeffrey heer

Field Summary

protected CopyOnWriteArrayList	m_params
protected int	m_pcount

Fields inherited from interface prefuse.data.expression.Function

VARARGS

Constructor Summary

protected

FunctionExpression(int parameterCount) Protected constructor.

Method Summary

protected void	addChildListeners() Add child listeners to catch and propagate sub-expression updates.
void	addParameter(Expression e) Add a parameter value sub-expression to this function.
abstract java.lang.String	getName() Get the name of this function.
int	getParameterCount() Get the maximum number of parameters accepted by this Function.
protected void	missingParams() Throw an exception when needed parameters are missing.
protected Expression	param(int idx) Return the parameter expression at the given index.
protected int	paramCount() An internal-only method that returns the current number of parameters collected.
protected void	removeChildListeners() Remove child listeners for sub-expression updates.
java.lang.String	toString()
void	visit(ExpressionVisitor v) Passes the visitor through this expression and any sub expressions

Methods inherited from class prefuse.data.expression.AbstractExpression

addExpressionListener, expressionChanged, fireExpressionChange, get, getBoolean, getDouble, getFloat, getInt, getLong, hasListeners, removeExpressionListener

Methods inherited from class java.lang.Object

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

Methods inherited from interface prefuse.data.expression.Expression

addExpressionListener, get, getBoolean, getDouble, getFloat, getInt, getLong, getType, removeExpressionListener

Field Detail

m_params

protected CopyOnWriteArrayList m_params

m_pcount

protected final int m_pcount

Constructor Detail

FunctionExpression

protected FunctionExpression(int parameterCount)

Protected constructor.

Parameters:

parameterCount - the max parameter count

Method Detail

getName

public abstract java.lang.String getName()

Description copied from interface: Function

Get the name of this function.

Specified by:

getName in interface Function

Returns:

the function name

See Also:

Function.getName()

addParameter

public void addParameter(Expression e)

Description copied from interface: Function

Add a parameter value sub-expression to this function.

Specified by:

addParameter in interface Function

Parameters:

e - the parameter sub-expression

See Also:

Function.addParameter(prefuse.data.expression.Expression)

paramCount

protected int paramCount()

An internal-only method that returns the current number of parameters collected.

param

protected final Expression param(int idx)

Return the parameter expression at the given index.

Parameters:

idx - the parameter index

Returns:

the parameter value Expression at the given index

getParameterCount

public int getParameterCount()

Description copied from interface: Function

Get the maximum number of parameters accepted by this Function.

Specified by:

getParameterCount in interface Function

Returns:

the maximum number of parametes accepted, or Function.VARARGS is the number is variable.

See Also:

Function.getParameterCount()

missingParams

protected void missingParams()

Throw an exception when needed parameters are missing.

visit

public void visit(ExpressionVisitor v)

Description copied from interface: Expression

Passes the visitor through this expression and any sub expressions

Specified by:

visit in interface Expression

Overrides:

visit in class AbstractExpression

Parameters:

v - the ExpressionVisitor

See Also:

Expression.visit(prefuse.data.expression.ExpressionVisitor)

addChildListeners

protected void addChildListeners()

Description copied from class: AbstractExpression

Add child listeners to catch and propagate sub-expression updates.

Overrides:

addChildListeners in class AbstractExpression

See Also:

AbstractExpression.addChildListeners()

removeChildListeners

protected void removeChildListeners()

Description copied from class: AbstractExpression

Remove child listeners for sub-expression updates.

Overrides:

removeChildListeners in class AbstractExpression

See Also:

AbstractExpression.removeChildListeners()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()