org.apache.calcite.linq4j.tree

Class DeterministicCodeOptimizer

java.lang.Object

org.apache.calcite.linq4j.tree.Shuttle

org.apache.calcite.linq4j.tree.ClassDeclarationFinder

org.apache.calcite.linq4j.tree.DeterministicCodeOptimizer

public class DeterministicCodeOptimizer
extends ClassDeclarationFinder

Factors out deterministic expressions to final static fields. Instances of this class should not be reused, so new visitor should be created for optimizing a new expression tree.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Expression,Boolean>	constants The map contains known to be effectively-final expression.
protected Map<Expression,ParameterExpression>	dedup The map that de-duplicates expressions, so the same expressions may reuse the same final static fields.
private static Set<Class>	DETERMINISTIC_CLASSES
private static String	FIELD_PREFIX
protected Map<String,ParameterExpression>	fieldsByName The map of all the added final static fields.
private static Pattern	NON_ASCII
private static Pattern	PREFIX_PATTERN

Fields inherited from class org.apache.calcite.linq4j.tree.ClassDeclarationFinder

addedDeclarations, parent

Constructor Summary

Constructors

Constructor and Description
DeterministicCodeOptimizer(ClassDeclarationFinder parent) Creates a child optimizer.

Method Summary

Modifier and Type	Method and Description
protected boolean	allMethodsDeterministic(Class klass) Checks if all the methods in given class are deterministic (i.e.
protected Expression	createField(Expression expression) Creates final static field to hold the given expression.
protected ParameterExpression	findDeclaredExpression(Expression expression) Finds if there exists ready for reuse declaration for given expression.
private <C> Constructor<C>	getConstructor(Class<C> klass)
protected DeterministicCodeOptimizer	goDeeper() Creates child visitor.
protected boolean	hasField(String name) Verifies if the variable name is already in use.
protected String	inventFieldName(Expression expression) Generates field name to store given expression.
protected boolean	isConstant(Expression expression) Verifies if the expression is effectively constant.
protected boolean	isConstructorDeterministic(NewExpression newExpression) Checks if new instance creation can be reused.
protected boolean	isMethodDeterministic(Method method) Checks if given method is deterministic (i.e.
protected void	learnFinalStaticDeclarations(List<MemberDeclaration> memberDeclarations) Processes the list of declarations and learns final static ones as effectively constant.
protected Expression	tryOptimizeMethodCall(MethodCallExpression methodCallExpression) Optimized method call, possibly converting it to final static field.
protected Expression	tryOptimizeNewInstance(NewExpression newExpression) Optimizes new Type() constructs,
Expression	visit(BinaryExpression binaryExpression, Expression expression0, Expression expression1)
MemberDeclaration	visit(FieldDeclaration fieldDeclaration, Expression initializer)
Expression	visit(MemberExpression memberExpression, Expression expression)
Expression	visit(MethodCallExpression methodCallExpression, Expression targetExpression, List<Expression> expressions)
Expression	visit(TernaryExpression ternaryExpression, Expression expression0, Expression expression1, Expression expression2)
Expression	visit(TypeBinaryExpression typeBinaryExpression, Expression expression)
Expression	visit(UnaryExpression unaryExpression, Expression expression)

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

create, create, create, isConstant, optimizeDeclarations, preVisit, preVisit, visit, visit

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

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

Methods inherited from class java.lang.Object

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

Field Detail

constants

protected final Map<Expression,Boolean> constants

The map contains known to be effectively-final expression. The map uses identity equality. Typically the key is ParameterExpression, however there might be non-factored to final field expression that is known to be constant. For instance, cast expression will not be factored to a field, but we still need to track its constant status.

dedup

protected final Map<Expression,ParameterExpression> dedup

The map that de-duplicates expressions, so the same expressions may reuse the same final static fields.

fieldsByName

protected final Map<String,ParameterExpression> fieldsByName

The map of all the added final static fields. Allows to identify if the name is occupied or not.

NON_ASCII

private static final Pattern NON_ASCII

FIELD_PREFIX

private static final String FIELD_PREFIX

See Also:

Constant Field Values

PREFIX_PATTERN

private static final Pattern PREFIX_PATTERN

DETERMINISTIC_CLASSES

private static final Set<Class> DETERMINISTIC_CLASSES

Constructor Detail

DeterministicCodeOptimizer

public DeterministicCodeOptimizer(ClassDeclarationFinder parent)

Creates a child optimizer. Typically a child is created for each class declaration, so each optimizer collects fields for exactly one class.

Parameters:

parent - parent optimizer

Method Detail

tryOptimizeNewInstance

protected Expression tryOptimizeNewInstance(NewExpression newExpression)

Optimizes new Type() constructs,

Overrides:

tryOptimizeNewInstance in class ClassDeclarationFinder

Parameters:

newExpression - expression to optimize

Returns:

optimized expression

visit

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

Overrides:

visit in class Shuttle

visit

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

Overrides:

visit in class Shuttle

visit

public Expression visit(UnaryExpression unaryExpression,
                        Expression expression)

Overrides:

visit in class Shuttle

visit

public Expression visit(TypeBinaryExpression typeBinaryExpression,
                        Expression expression)

Overrides:

visit in class Shuttle

tryOptimizeMethodCall

protected Expression tryOptimizeMethodCall(MethodCallExpression methodCallExpression)

Optimized method call, possibly converting it to final static field.

Parameters:

methodCallExpression - method call to optimize

Returns:

optimized expression

visit

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

Overrides:

visit in class Shuttle

visit

public Expression visit(MemberExpression memberExpression,
                        Expression expression)

Overrides:

visit in class Shuttle

visit

public MemberDeclaration visit(FieldDeclaration fieldDeclaration,
                               Expression initializer)

Overrides:

visit in class Shuttle

learnFinalStaticDeclarations

protected void learnFinalStaticDeclarations(List<MemberDeclaration> memberDeclarations)

Processes the list of declarations and learns final static ones as effectively constant.

Overrides:

learnFinalStaticDeclarations in class ClassDeclarationFinder

Parameters:

memberDeclarations - list of declarations to search finals from

findDeclaredExpression

protected ParameterExpression findDeclaredExpression(Expression expression)

Finds if there exists ready for reuse declaration for given expression.

Overrides:

findDeclaredExpression in class ClassDeclarationFinder

Parameters:

expression - input expression

Returns:

parameter of the already existing declaration, or null

createField

protected Expression createField(Expression expression)

Creates final static field to hold the given expression. The method might reuse existing declarations if appropriate.

Parameters:

expression - expression to store in final field

Returns:

expression for the given input expression

inventFieldName

protected String inventFieldName(Expression expression)

Generates field name to store given expression. The expression is converted to string and all the non-ascii/numeric characters are replaced with underscores and "_$L4J$C$" suffix is added to avoid conflicts with other variables. When multiple variables are mangled to the same name, counter is used to avoid conflicts.

Parameters:

expression - input expression

Returns:

unique name to store given expression

isConstant

protected boolean isConstant(Expression expression)

Verifies if the expression is effectively constant. It is assumed the expression is simple (e.g. ConstantExpression or ParameterExpression). The method verifies parent chain since the expression might be defined in enclosing class.

Overrides:

isConstant in class ClassDeclarationFinder

Parameters:

expression - expression to test

Returns:

true when the expression is known to be constant

isMethodDeterministic

protected boolean isMethodDeterministic(Method method)

Checks if given method is deterministic (i.e. returns the same output given the same inputs).

Parameters:

method - method to test

Returns:

true when the method is deterministic

isConstructorDeterministic

protected boolean isConstructorDeterministic(NewExpression newExpression)

Checks if new instance creation can be reused. For instance new BigInteger("42") is effectively final and can be reused.

Parameters:

newExpression - method to test

Returns:

true when the method is deterministic

getConstructor

private <C> Constructor<C> getConstructor(Class<C> klass)

allMethodsDeterministic

protected boolean allMethodsDeterministic(Class klass)

Checks if all the methods in given class are deterministic (i.e. return the same value given the same inputs)

Parameters:

klass - class to test

Returns:

true when all the methods including constructors are deterministic

hasField

protected boolean hasField(String name)

Verifies if the variable name is already in use. Only the variables that are explicitly added to fieldsByName are verified. The method verifies parent chain.

Overrides:

hasField in class ClassDeclarationFinder

Parameters:

name - name of the variable to test

Returns:

true if the name is used by one of static final fields

goDeeper

protected DeterministicCodeOptimizer goDeeper()

Creates child visitor. It is used to traverse nested class declarations.

Overrides:

goDeeper in class ClassDeclarationFinder

Returns:

new Visitor that is used to optimize class declarations