Package org.codehaus.groovy.transform.sc.transformers

Class CompareToNullExpression

java.lang.Object

org.codehaus.groovy.ast.ASTNode

org.codehaus.groovy.ast.AnnotatedNode

org.codehaus.groovy.ast.expr.Expression

org.codehaus.groovy.ast.expr.BinaryExpression

org.codehaus.groovy.transform.sc.transformers.CompareToNullExpression

All Implemented Interfaces:

GroovydocHolder<AnnotatedNode>, NodeMetaDataHandler

public class CompareToNullExpression
extends BinaryExpression

Specializes a comparison against null for static compilation.

Field Summary

Fields inherited from class org.codehaus.groovy.ast.expr.Expression

EMPTY_ARRAY

Fields inherited from interface groovy.lang.groovydoc.GroovydocHolder

DOC_COMMENT

Constructor Summary

Constructors

Constructor	Description
CompareToNullExpression(Expression expression, boolean equalsNull)	Creates a comparison between an expression and null.

Method Summary

Modifier and Type	Method	Description
Expression	getObjectExpression()	Returns the expression being compared with null.
void	setLeftExpression(Expression expression)	Prevents replacing the compared expression after construction.
void	setRightExpression(Expression expression)	Prevents changing the fixed null right-hand operand.
void	setType(ClassNode type)	Prevents changing the fixed boolean result type of this expression.
Expression	transformExpression(ExpressionTransformer transformer)	Transforms the compared expression while preserving the null-comparison semantics.
void	visit(GroovyCodeVisitor visitor)	Emits direct null-comparison bytecode for this expression.

Methods inherited from class org.codehaus.groovy.ast.expr.BinaryExpression

getLeftExpression, getOperation, getRightExpression, getText, isSafe, newAssignmentExpression, newInitializationExpression, setSafe, toString

Methods inherited from class org.codehaus.groovy.ast.expr.Expression

getType, transformExpressions, transformExpressions

Methods inherited from class org.codehaus.groovy.ast.AnnotatedNode

addAnnotation, addAnnotation, addAnnotations, getAnnotations, getAnnotations, getDeclaringClass, getGroovydoc, getInstance, hasNoRealSourcePosition, isSynthetic, setDeclaringClass, setHasNoRealSourcePosition, setSynthetic

Methods inherited from class org.codehaus.groovy.ast.ASTNode

copyNodeMetaData, getColumnNumber, getLastColumnNumber, getLastLineNumber, getLineNumber, getMetaDataMap, setColumnNumber, setLastColumnNumber, setLastLineNumber, setLineNumber, setMetaDataMap, setSourcePosition

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.codehaus.groovy.ast.NodeMetaDataHandler

copyNodeMetaData, getNodeMetaData, getNodeMetaData, getNodeMetaData, newMetaDataMap, putNodeMetaData, removeNodeMetaData, setNodeMetaData

Constructor Details

CompareToNullExpression

public CompareToNullExpression(Expression expression,
 boolean equalsNull)

Creates a comparison between an expression and null.

Parameters:

expression - the expression being compared

equalsNull - true for == null; false for != null

Method Details

getObjectExpression

public Expression getObjectExpression()

Returns the expression being compared with null.

Returns:

the compared expression

setLeftExpression

public void setLeftExpression(Expression expression)

Prevents replacing the compared expression after construction.

Overrides:

setLeftExpression in class BinaryExpression

Parameters:

expression - ignored

Throws:

UnsupportedOperationException - always

setRightExpression

public void setRightExpression(Expression expression)

Prevents changing the fixed null right-hand operand.

Overrides:

setRightExpression in class BinaryExpression

Parameters:

expression - ignored

Throws:

UnsupportedOperationException - always

setType

public void setType(ClassNode type)

Prevents changing the fixed boolean result type of this expression.

Overrides:

setType in class Expression

Parameters:

type - ignored

Throws:

UnsupportedOperationException - always

transformExpression

public Expression transformExpression(ExpressionTransformer transformer)

Transforms the compared expression while preserving the null-comparison semantics.

Overrides:

transformExpression in class BinaryExpression

Parameters:

transformer - the expression transformer to apply

Returns:

a transformed null-comparison expression

visit

public void visit(GroovyCodeVisitor visitor)

Emits direct null-comparison bytecode for this expression.

Overrides:

visit in class BinaryExpression

Parameters:

visitor - the visitor to accept