cetus.hir

Class MinMaxExpression

java.lang.Object

cetus.hir.Expression

cetus.hir.MinMaxExpression

All Implemented Interfaces:

Printable, Traversable, java.lang.Cloneable, java.lang.Comparable<Expression>

public class MinMaxExpression
extends Expression

Class for MIN() MAX() expressions - these are equivalent to conditional expressions.

Constructor Summary

Constructors

Constructor and Description
MinMaxExpression(boolean ismin) Constructs a min/max expression with the specified operator description.
MinMaxExpression(boolean ismin, Expression lhs, Expression rhs) Consructs a min/max expression with the specified operator flag and the two operand expressions.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(Expression e) Adds an operand at the end of the operand list.
int	compareTo(Expression e) Compares the min/max expression to the specified expression for order.
java.lang.Integer	compareTo(int num) Compares MinMaxExpression to an integer value.
static void	defaultPrint(MinMaxExpression m, java.io.PrintWriter o) Prints out MIN/MAX expressions on the specified print writer.
boolean	equals(java.lang.Object o) Checks if the given object is has the same type with this expression and its children is same with this expression's.
int	hashCode(int h) Returns cumulative hash code with the given initial value, h.
boolean	isMin() Returns true if this is a MIN expression.
boolean	isNegMin() Checks if this expression is a MIN expression having at least one operand with negative value.
boolean	isPosMax() Checks if this expression is a MIN expression having at least one operand with positive value.
Expression	negate() Negates the expression by switching the operator and the signs of the operands.
void	setMin(boolean ismin) Sets the operator with the specified flag.
Expression	simplify() Simplifies a MinMaxExpression as much as possible by removing duplicates and by matching special cases.
Expression	toConditionalExpression() Converts MinMaxExpression to an equivalent conditional expression.
java.lang.String	toString() Returns a string representation of the expression

Methods inherited from class cetus.hir.Expression

clone, findExpression, getChildren, getParent, getStatement, hashCode, needsParens, print, printSelf, removeChild, setChild, setParens, setParent, setPrintMethod, swapWith, verify

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MinMaxExpression

public MinMaxExpression(boolean ismin)

Constructs a min/max expression with the specified operator description.

Parameters:

ismin - true for MIN, false for MAX.

MinMaxExpression

public MinMaxExpression(boolean ismin,
                Expression lhs,
                Expression rhs)

Consructs a min/max expression with the specified operator flag and the two operand expressions.

Parameters:

ismin - true if the operator is MIN, false otherwise

lhs - the first operand

rhs - the second operand

Throws:

java.lang.IllegalArgumentException - if lhs or rhs is invalid.

NotAnOrphanException - if lhs or rhs has a parent.

Method Detail

defaultPrint

public static void defaultPrint(MinMaxExpression m,
                java.io.PrintWriter o)

Prints out MIN/MAX expressions on the specified print writer.

toString

public java.lang.String toString()

Description copied from class: Expression

Returns a string representation of the expression

Overrides:

toString in class Expression

hashCode

public int hashCode(int h)

Description copied from class: Expression

Returns cumulative hash code with the given initial value, h. This is intended for optimizing memory usage when computing hash code of an expression object. Previous approach constructs a string representation of the expression to get the hash code while this approach uses the same algorithm as String.hashCode() without creating a string. All sub classes of Expression have there specific implementations of this method and Expression.hashCode() simply returns hashCode(0).

isMin

public boolean isMin()

Returns true if this is a MIN expression.

Returns:

true if this is a MIN expression, false otherwise

setMin

public void setMin(boolean ismin)

Sets the operator with the specified flag.

Parameters:

ismin - true for MIN, false for MAX

add

public void add(Expression e)

Adds an operand at the end of the operand list.

Parameters:

e - the new operand to be appended.

Throws:

java.lang.IllegalArgumentException - if e is invalid.

NotAnOrphanException - if e has a parent.

negate

public Expression negate()

Negates the expression by switching the operator and the signs of the operands.

Returns:

the negated expression

isPosMax

public boolean isPosMax()

Checks if this expression is a MIN expression having at least one operand with positive value.

Returns:

true/false

isNegMin

public boolean isNegMin()

Checks if this expression is a MIN expression having at least one operand with negative value.

Returns:

true/false

simplify

public Expression simplify()

Simplifies a MinMaxExpression as much as possible by removing duplicates and by matching special cases.

Returns:

A simplified expression

compareTo

public int compareTo(Expression e)

Compares the min/max expression to the specified expression for order.

Specified by:

compareTo in interface java.lang.Comparable<Expression>

Overrides:

compareTo in class Expression

compareTo

public java.lang.Integer compareTo(int num)

Compares MinMaxExpression to an integer value.

Parameters:

num - an integer value

Returns:

Integer object if comparison is possible, null otherwise

toConditionalExpression

public Expression toConditionalExpression()

Converts MinMaxExpression to an equivalent conditional expression.

Returns:

the converted conditional expression

equals

public boolean equals(java.lang.Object o)

Description copied from class: Expression

Checks if the given object is has the same type with this expression and its children is same with this expression's. The sub classes of expression should call this method first and proceed with more checking if they have additional fields to be checked.

Overrides:

equals in class Expression

Parameters:

o - the object to be compared with.

Returns:

true if o!=null, this.getClass()==o.getClass(), and this.children.equals(o.children) || this.children==o.children==null