org.apache.calcite.linq4j.tree

Class OptimizeVisitor

java.lang.Object

org.apache.calcite.linq4j.tree.Visitor

org.apache.calcite.linq4j.tree.OptimizeVisitor

public class OptimizeVisitor
extends Visitor

Visitor that optimizes expressions.

The optimizations are essential, not mere tweaks. Without optimization, expressions such as false == null will be left in, which are invalid to Janino (because it does not automatically box primitives).

Field Summary

Fields

Modifier and Type	Field and Description
private static Method	BOOLEAN_VALUEOF_BOOL
static MemberExpression	BOXED_FALSE_EXPR
static MemberExpression	BOXED_TRUE_EXPR
static Statement	EMPTY_STATEMENT
static ConstantExpression	FALSE_EXPR
private static Set<Method>	KNOWN_NON_NULL_METHODS
private static Map<ExpressionType,ExpressionType>	NOT_BINARY_COMPLEMENT
static ConstantExpression	TRUE_EXPR

Constructor Summary

Constructors

Constructor and Description
OptimizeVisitor()

Method Summary

Methods

Modifier and Type	Method and Description
private static void	addComplement(ExpressionType eq, ExpressionType ne)
private static Boolean	always(Expression x) Returns whether an expression always evaluates to true or false.
private static boolean	eq(Expression a, Expression b) Treats two expressions equal even if they represent different null types
private boolean	isConstantNull(Expression expression)
protected boolean	isKnownNotNull(Expression expression) Returns whether an expression always returns a non-null result.
Expression	visit(BinaryExpression binary, Expression expression0, Expression expression1)
Statement	visit(ConditionalStatement conditionalStatement, List<Node> list)
Expression	visit(MethodCallExpression methodCallExpression, Expression targetExpression, List<Expression> expressions)
Expression	visit(TernaryExpression ternary, Expression expression0, Expression expression1, Expression expression2)
Expression	visit(UnaryExpression unaryExpression, Expression expression)
private Expression	visit0(BinaryExpression binary, Expression expression0, Expression expression1)

Methods inherited from class org.apache.calcite.linq4j.tree.Visitor

preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, preVisit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class java.lang.Object

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

Field Detail

FALSE_EXPR

public static final ConstantExpression FALSE_EXPR

TRUE_EXPR

public static final ConstantExpression TRUE_EXPR

BOXED_FALSE_EXPR

public static final MemberExpression BOXED_FALSE_EXPR

BOXED_TRUE_EXPR

public static final MemberExpression BOXED_TRUE_EXPR

EMPTY_STATEMENT

public static final Statement EMPTY_STATEMENT

KNOWN_NON_NULL_METHODS

private static final Set<Method> KNOWN_NON_NULL_METHODS

NOT_BINARY_COMPLEMENT

private static final Map<ExpressionType,ExpressionType> NOT_BINARY_COMPLEMENT

BOOLEAN_VALUEOF_BOOL

private static final Method BOOLEAN_VALUEOF_BOOL

Constructor Detail

OptimizeVisitor

public OptimizeVisitor()

Method Detail

addComplement

private static void addComplement(ExpressionType eq,
                 ExpressionType ne)

visit

public Expression visit(TernaryExpression ternary,
               Expression expression0,
               Expression expression1,
               Expression expression2)

Overrides:

visit in class Visitor

visit

public Expression visit(BinaryExpression binary,
               Expression expression0,
               Expression expression1)

Overrides:

visit in class Visitor

visit0

private Expression visit0(BinaryExpression binary,
                Expression expression0,
                Expression expression1)

visit

public Expression visit(UnaryExpression unaryExpression,
               Expression expression)

Overrides:

visit in class Visitor

visit

public Statement visit(ConditionalStatement conditionalStatement,
              List<Node> list)

Overrides:

visit in class Visitor

visit

public Expression visit(MethodCallExpression methodCallExpression,
               Expression targetExpression,
               List<Expression> expressions)

Overrides:

visit in class Visitor

isConstantNull

private boolean isConstantNull(Expression expression)

always

private static Boolean always(Expression x)

Returns whether an expression always evaluates to true or false. Assumes that expression has already been optimized.

isKnownNotNull

protected boolean isKnownNotNull(Expression expression)

Returns whether an expression always returns a non-null result. For instance, primitive types cannot contain null values.

Parameters:

expression - expression to test

Returns:

true when the expression is known to be not-null

eq

private static boolean eq(Expression a,
         Expression b)

Treats two expressions equal even if they represent different null types