dk.rode.thesis.interpreter
Class NotExpression

java.lang.Object
  dk.rode.thesis.interpreter.AbstractExpression<Boolean>
      dk.rode.thesis.interpreter.NotExpression

All Implemented Interfaces:

Expression<Boolean>, NonTerminalExpression<Boolean>, Copyable<Expression<Boolean>>, StrictCopyable<Expression<Boolean>>

public class NotExpression
extends AbstractExpression<Boolean>
implements NonTerminalExpression<Boolean>

A not expression (!) for any expression evaluating to a Boolean value.

This class does not declare a copy constructor, but can still be copied.

Author:

Gunni Rode / rode.dk

See Also:

AndExpression, OrExpression, CompareExpression, EqualExpression

Nested Class Summary

Nested classes/interfaces inherited from interface dk.rode.thesis.interpreter.Expression

Expression.SymbolIdiom

Field Summary

private Expression<Boolean>

expression The expression to evaluated and the result negated.

Constructor Summary

NotExpression(Expression<Boolean> expression)
Constructor.

Method Summary

String	asSymbol(Context context) Returns {@code (!
NotExpression	copy() Copies this expression.
Boolean	evaluate(Context context) Evaluates this expression and returns the result.
String	name() The stand-alone symbol name for this expression.
List<Expression<?>>	operands() Returns the expression operands used by this expression, in order.
String	toString() Returns the string representation of this expression.

Methods inherited from class dk.rode.thesis.interpreter.AbstractExpression

contains, equals, hashCode

Methods inherited from class java.lang.Object

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

Methods inherited from interface dk.rode.thesis.interpreter.Expression

contains

Field Detail

expression

private final Expression<Boolean> expression

The expression to evaluated and the result negated.

Never null.

Constructor Detail

NotExpression

public NotExpression(Expression<Boolean> expression)

Constructor.

Parameters:

expression - The expression to use; cannot be null and is not copied.

Throws:

NullPointerException - If expression is null.

Method Detail

asSymbol

public String asSymbol(Context context)
                throws ExpressionException

Returns (!x), where x is the symbol representation of the expression negated by this expression.

Specified by:

asSymbol in interface Expression<Boolean>

Parameters:

context - The context to use; never null.

Returns:

The symbolic representation; never null.

Throws:

ExpressionException - If the symbol cannot be generated.

See Also:

Expression.contains(Expression)

copy

public NotExpression copy()

Description copied from interface: Expression

Copies this expression.

Unlike Expression.asSymbol(Context), copying cannot handle cyclic expression references!

Specified by:

copy in interface Expression<Boolean>

Specified by:

copy in interface Copyable<Expression<Boolean>>

Returns:

A copy of this expression; never null.

evaluate

public Boolean evaluate(Context context)
                 throws ExpressionException

Description copied from interface: Expression

Evaluates this expression and returns the result.

There is no guarantee that the evaluation of this expression will terminate!

Specified by:

evaluate in interface Expression<Boolean>

Parameters:

context - The context to use; cannot be null.

Returns:

The result of the evaluation; never null.

Throws:

ExpressionException - If the evaluation fails.

name

public final String name()

Description copied from interface: Expression

The stand-alone symbol name for this expression.

Specified by:

name in interface Expression<Boolean>

Returns:

not

operands

public List<Expression<?>> operands()

Description copied from interface: Expression

Returns the expression operands used by this expression, in order.

Modifying the returned list will not affect this expression.

Specified by:

operands in interface Expression<Boolean>

Returns:

The operands; never null, but can be empty.

toString

public String toString()

Description copied from class: AbstractExpression

Returns the string representation of this expression.

Specified by:

toString in interface Expression<Boolean>

Overrides:

toString in class AbstractExpression<Boolean>

Returns:

The string representation; never null.