dk.rode.thesis.interpreter
Class AndExpression

java.lang.Object
  dk.rode.thesis.interpreter.AbstractExpression<E>
      dk.rode.thesis.interpreter.BinaryExpression<Boolean,Boolean>
          dk.rode.thesis.interpreter.AndExpression

All Implemented Interfaces:

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

@Participant(value="NonTerminalExpression")
public class AndExpression
extends BinaryExpression<Boolean,Boolean>
implements NonTerminalExpression<Boolean>

A logical and expression for two expressions evaluating to a Boolean value.

The logical AND operation may or may not be short-circuit, which is determined at construction time.

The evaluation of a logical short-circuit AND expression is not commutative.

Author:

Gunni Rode / rode.dk

See Also:

OrExpression, NotExpression, CompareExpression, EqualExpression

Nested Class Summary

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

Expression.SymbolIdiom

Field Summary

boolean

shortCircuit True if a short-circuit logical AND operation is used, i.e.

Fields inherited from class dk.rode.thesis.interpreter.BinaryExpression

first, second

Constructor Summary

AndExpression(AndExpression expression)
Copy constructor.

AndExpression(boolean shortCircuit, Expression<Boolean> first, Expression<Boolean> second)
Constructor.

AndExpression(Expression<Boolean> first, Expression<Boolean> second)
Constructor.

Method Summary

String	asSymbol(Context context) Returns (x && y) if short-circuit, or (x & y), where x is the symbolic representation of the first expression operand and y of the second.
AndExpression	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.

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

asSymbol, asSymbol, operands, toString

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, operands, toString

Field Detail

shortCircuit

public final boolean shortCircuit

True if a short-circuit logical AND operation is used, i.e. &&, false if not, i.e. &.

Constructor Detail

AndExpression

public AndExpression(AndExpression expression)

Copy constructor.

Parameters:

expression - The expression to copy; cannot be null.

Throws:

NullPointerException - If expression is null.

AndExpression

public AndExpression(boolean shortCircuit,
                     Expression<Boolean> first,
                     Expression<Boolean> second)

Constructor.

The logical AND operation performed is short-circuit, i.e. &&, if shortCircuit is true, otherwise not, i.e &.

Parameters:

shortCircuit - True for short-circuit (&&).

first - The first expression operand; cannot be null.

second - The second expression operand; cannot be null.

Throws:

NullPointerException - If either expression is null.

AndExpression

public AndExpression(Expression<Boolean> first,
                     Expression<Boolean> second)

Constructor.

The logical AND operation performed is short-circuit, i.e. &&.

Parameters:

first - The first expression operand; cannot be null.

second - The second expression operand; cannot be null.

Throws:

NullPointerException - If either expression is null.

Method Detail

asSymbol

public String asSymbol(Context context)
                throws ExpressionException

Returns (x && y) if short-circuit, or (x & y), where x is the symbolic representation of the first expression operand and y of the second.

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 AndExpression 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:

and