prefuse.data.expression
Class AbstractExpression

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

All Implemented Interfaces:

java.util.EventListener, ExpressionListener, Expression

Direct Known Subclasses:

AbstractPredicate, BinaryExpression, ColumnExpression, FunctionExpression, GroupExpression, IfExpression, Literal

public abstract class AbstractExpression
extends java.lang.Object
implements Expression, ExpressionListener

Abstract base class for Expression implementations. Provides support for listeners and defaults every Expression evaluation method to an unsupported operation.

Author:

jeffrey heer

Constructor Summary

AbstractExpression()

Method Summary

protected void	addChildListeners() Add child listeners to catch and propagate sub-expression updates.
void	addExpressionListener(ExpressionListener lstnr) Add a listener to this Expression.
void	expressionChanged(Expression expr) Relay an expression change event.
protected void	fireExpressionChange() Fire an expression change.
java.lang.Object	get(Tuple t) By default, throws an UnsupportedOperationException.
boolean	getBoolean(Tuple t) By default, throws an UnsupportedOperationException.
double	getDouble(Tuple t) By default, throws an UnsupportedOperationException.
float	getFloat(Tuple t) By default, throws an UnsupportedOperationException.
int	getInt(Tuple t) By default, throws an UnsupportedOperationException.
long	getLong(Tuple t) By default, throws an UnsupportedOperationException.
protected boolean	hasListeners() Indicates if any listeners are registered with this Expression.
protected void	removeChildListeners() Remove child listeners for sub-expression updates.
void	removeExpressionListener(ExpressionListener lstnr) Remove a listener to this Expression.
void	visit(ExpressionVisitor v) Passes the visitor through this expression and any sub expressions

Methods inherited from class java.lang.Object

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

Methods inherited from interface prefuse.data.expression.Expression

getType

Constructor Detail

AbstractExpression

public AbstractExpression()

Method Detail

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

Parameters:

v - the ExpressionVisitor

See Also:

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

addExpressionListener

public final void addExpressionListener(ExpressionListener lstnr)

Description copied from interface: Expression

Add a listener to this Expression.

Specified by:

addExpressionListener in interface Expression

Parameters:

lstnr - the expression listener to add

See Also:

Expression.addExpressionListener(prefuse.data.event.ExpressionListener)

removeExpressionListener

public final void removeExpressionListener(ExpressionListener lstnr)

Description copied from interface: Expression

Remove a listener to this Expression.

Specified by:

removeExpressionListener in interface Expression

Parameters:

lstnr - the expression listener to remove

See Also:

Expression.removeExpressionListener(prefuse.data.event.ExpressionListener)

hasListeners

protected final boolean hasListeners()

Indicates if any listeners are registered with this Expression.

Returns:

true if listeners are registered, false otherwise

fireExpressionChange

protected final void fireExpressionChange()

Fire an expression change.

addChildListeners

protected void addChildListeners()

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

removeChildListeners

protected void removeChildListeners()

Remove child listeners for sub-expression updates.

expressionChanged

public void expressionChanged(Expression expr)

Relay an expression change event.

Specified by:

expressionChanged in interface ExpressionListener

Parameters:

expr - the modified expression

See Also:

ExpressionListener.expressionChanged(prefuse.data.expression.Expression)

get

public java.lang.Object get(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

get in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as an Object

See Also:

Expression.get(prefuse.data.Tuple)

getInt

public int getInt(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

getInt in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as an int

See Also:

Expression.getInt(prefuse.data.Tuple)

getLong

public long getLong(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

getLong in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as a long

See Also:

Expression.getLong(prefuse.data.Tuple)

getFloat

public float getFloat(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

getFloat in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as a float

See Also:

Expression.getFloat(prefuse.data.Tuple)

getDouble

public double getDouble(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

getDouble in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as a double

See Also:

Expression.getDouble(prefuse.data.Tuple)

getBoolean

public boolean getBoolean(Tuple t)

By default, throws an UnsupportedOperationException.

Specified by:

getBoolean in interface Expression

Parameters:

t - the input Tuple

Returns:

the Expression return value, as a boolean

See Also:

Expression.getBoolean(prefuse.data.Tuple)