openjava.ptree
Class UnaryExpression

java.lang.Object
  |
  +--openjava.ptree.ParseTreeObject
        |
        +--openjava.ptree.NonLeaf
              |
              +--openjava.ptree.UnaryExpression

All Implemented Interfaces:

Cloneable, Expression, ParseTree, VariableInitializer

public class UnaryExpression

extends NonLeaf

implements Expression

The UnaryExpression class presents for an expression which consists of unary operator with one Expression.
The unary expressions are :

expr++, expr--, ++expr, --expr, ^expr, !expr, +expr or -expr

,where expr is an expression.
If the operator in the expression of the operand has week unity, this automatically produces the code in which the operand is enclosed by parenthesises.
In the case the operand is y = x and the urary operator is +, this produces the code :

     +(y = x)
 

See Also:

NonLeaf, Expression

Field Summary

static int	BIT_NOT Post increment operator.
static int	EXISTS Exists operator.
static int	MINUS Post increment operator.
static int	NOT Post increment operator.
private int	opr operator
private static String[]	opr_string
static int	PLUS Post increment operator.
static int	POST_DECREMENT Post decrement operator.
static int	POST_INCREMENT Post increment operator.
static int	PRE_DECREMENT Post increment operator.
static int	PRE_INCREMENT Pre increment operator.

Fields inherited from class openjava.ptree.NonLeaf

Fields inherited from class openjava.ptree.ParseTreeObject

debugFlag, debugLevel, LN, out, writerStack

Constructor Summary

(package private)	UnaryExpression()
	UnaryExpression(Expression expr, int opr) Allocates a new object.
	UnaryExpression(int opr, Expression expr) Allocates a new object.

Method Summary

void	accept(ParseTreeVisitor v) Accepts a ParseTreeVisitor object as the role of a Visitor in the Visitor pattern, as the role of an Element in the Visitor pattern.
Expression	getExpression() Gets the expression operated in this expression.
int	getOperator() Gets the operator of this unary expression.
OJClass	getType(Environment env)
boolean	isPostfix() Tests if the operator of unary expression is a postfix operator.
boolean	isPrefix() Tests if the operator of unary expression is a prefix operator.
ParseTree	makeCopy() Makes a new copy of this nonleaf-node as a ptree-node.
ParseTree	makeRecursiveCopy() Makes a new copy (another object) of this nonleaf-node recursively.
String	operatorString()
void	setExpression(Expression expr) Sets the expression operated in this expression.
void	setOperator(int opr) Sets the operator of this unary expression.
void	writeCode() Writes the code this parse-tree presents for.

Methods inherited from class openjava.ptree.NonLeaf

childrenAccept, childrenAreEqual, elementAt, equals, getComment, getContents, getLength, getRowType, replaceChildWith, set, set, set, set, set, set, set, set, set, setComment, setElementAt

Methods inherited from class openjava.ptree.ParseTreeObject

clone, eq, eq, equal, flushPrintWriter, getDebugFlag, getNest, getObjectID, getParent, getPrintWriter, getTab, hashCode, lastObjectID, popNest, popPrintWriter, pushNest, pushPrintWriter, replace, setDebugFlag, setDebugLevel, setNest, setParent, setPrintStream, setTab, toFlattenString, toString, writeDebug, writeDebugL, writeDebugLln, writeDebugln, writeDebugLR, writeDebugR, writeDebugRln, writeTab

Methods inherited from class java.lang.Object

equals, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface openjava.ptree.Expression

getRowType

Methods inherited from interface openjava.ptree.ParseTree

childrenAccept, eq, equals, getObjectID, replace, toFlattenString, toString

Field Detail

POST_INCREMENT

public static final int POST_INCREMENT

Post increment operator. For example:

     i++
 

See Also:

Constant Field Values

POST_DECREMENT

public static final int POST_DECREMENT

Post decrement operator. For example:

     i--
 

See Also:

Constant Field Values

PRE_INCREMENT

public static final int PRE_INCREMENT

Pre increment operator. For example:

     ++i
 

See Also:

Constant Field Values

PRE_DECREMENT

public static final int PRE_DECREMENT

Post increment operator. For example:

     --i
 

See Also:

Constant Field Values

BIT_NOT

public static final int BIT_NOT

Post increment operator. For example:

     ~i
 

See Also:

Constant Field Values

NOT

public static final int NOT

Post increment operator. For example:

     ! c
 

See Also:

Constant Field Values

PLUS

public static final int PLUS

Post increment operator. For example:

     +i
 

See Also:

Constant Field Values

MINUS

public static final int MINUS

Post increment operator. For example:

     -i
 

See Also:

Constant Field Values

EXISTS

public static final int EXISTS

Exists operator. For example:

     exists (select from emp)
 

See Also:

Constant Field Values

opr_string

private static final String[] opr_string

opr

private int opr

operator

Constructor Detail

UnaryExpression

public UnaryExpression(int opr,
                       Expression expr)

Allocates a new object.

Parameters:

opr - the operator of this unary expression.

expr - the expression.

UnaryExpression

public UnaryExpression(Expression expr,
                       int opr)

Allocates a new object.

Parameters:

expr - the expression.

opr - the operator of this unary expression.

UnaryExpression

UnaryExpression()

Method Detail

makeRecursiveCopy

public ParseTree makeRecursiveCopy()

Description copied from interface: ParseTree

Makes a new copy (another object) of this nonleaf-node recursively. The objects contained by this object will also be copied.

Specified by:

makeRecursiveCopy in interface ParseTree

Overrides:

makeRecursiveCopy in class NonLeaf

Returns:

the copy of this nonleaf-node as a ptree-node.

makeCopy

public ParseTree makeCopy()

Description copied from interface: ParseTree

Makes a new copy of this nonleaf-node as a ptree-node. The objects contained by the new object are same as these contained by the original object.

Specified by:

makeCopy in interface ParseTree

Overrides:

makeCopy in class ParseTreeObject

Returns:

the copy of this nonleaf-node as a ptree-node.

writeCode

public void writeCode()

Description copied from class: NonLeaf

Writes the code this parse-tree presents for.

Specified by:

writeCode in interface ParseTree

Overrides:

writeCode in class NonLeaf

getExpression

public Expression getExpression()

Gets the expression operated in this expression.

Returns:

the expression.

setExpression

public void setExpression(Expression expr)

Sets the expression operated in this expression.

Parameters:

expr - the expression to set.

getOperator

public int getOperator()

Gets the operator of this unary expression.

Returns:

the operator.

See Also:

POST_INCREMENT, POST_DECREMENT, PRE_INCREMENT, PRE_DECREMENT, BIT_NOT, NOT, PLUS, MINUS, EXISTS

setOperator

public void setOperator(int opr)

Sets the operator of this unary expression.

Parameters:

opr - the operator id to set.

See Also:

POST_INCREMENT, POST_DECREMENT, PRE_INCREMENT, PRE_DECREMENT, BIT_NOT, NOT, PLUS, MINUS, EXISTS

isPostfix

public boolean isPostfix()

Tests if the operator of unary expression is a postfix operator.

Returns:

true if the operator is postfix.

isPrefix

public boolean isPrefix()

Tests if the operator of unary expression is a prefix operator.

Returns:

true if the operator is prefix.

operatorString

public String operatorString()

accept

public void accept(ParseTreeVisitor v)
            throws ParseTreeException

Description copied from interface: ParseTree

Accepts a ParseTreeVisitor object as the role of a Visitor in the Visitor pattern, as the role of an Element in the Visitor pattern.

This invoke an appropriate visit() method on the accepted visitor.

Specified by:

accept in interface ParseTree

Specified by:

accept in class ParseTreeObject

Parameters:

v - a visitor

ParseTreeException

getType

public OJClass getType(Environment env)
                throws Exception

Specified by:

getType in interface Expression

Exception