org.apache.calcite.linq4j.tree

Class BlockBuilder

java.lang.Object

org.apache.calcite.linq4j.tree.BlockBuilder

public class BlockBuilder
extends Object

Builder for BlockStatement.

Has methods that help ensure that variable names are unique.

Constructor Summary

Constructors

Constructor and Description
BlockBuilder() Creates a non-optimizing BlockBuilder.
BlockBuilder(boolean optimizing) Creates a BlockBuilder.
BlockBuilder(boolean optimizing, @Nullable BlockBuilder parent) Creates a BlockBuilder.

Method Summary

Modifier and Type	Method and Description
void	add(Expression expression)
void	add(Statement statement)
protected void	addExpressionForReuse(DeclarationStatement decl)
BlockBuilder	append(Expression expression)
Expression	append(String name, BlockStatement block) Appends a block to a list of statements and returns an expression (possibly a variable) that represents the result of the newly added block.
Expression	append(String name, BlockStatement block, boolean optimize) Appends an expression to a list of statements, optionally optimizing it to a variable if it is used more than once.
Expression	append(String name, Expression expression) Appends an expression to a list of statements, and returns an expression (possibly a variable) that represents the result of the newly added block.
Expression	append(String name, Expression expression, boolean optimize) Appends an expression to a list of statements, optionally optimizing if the expression is used more than once.
@PolyNull Expression	appendIfNotNull(String name, @PolyNull Expression expression) Appends an expression to a list of statements if it is not null, and returns the expression.
void	clear() Clears this BlockBuilder.
protected Shuttle	createFinishingOptimizeShuttle() Creates a final optimization shuttle.
protected Shuttle	createOptimizeShuttle() Creates a shuttle that will be used during block optimization.
@Nullable DeclarationStatement	getComputedExpression(Expression expr) Returns the reference to ParameterExpression if given expression was already computed and stored to local variable.
boolean	hasVariable(String name)
protected boolean	isSafeForReuse(DeclarationStatement decl)
protected boolean	isSimpleExpression(@Nullable Expression expr) Checks if expression is simple enough to always inline at zero cost.
String	newName(String suggestion) Creates a name for a new variable, unique within this block.
BlockStatement	toBlock() Returns a block consisting of the current list of statements.
BlockBuilder	withRemoveUnused(boolean removeUnused)

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockBuilder

public BlockBuilder()

Creates a non-optimizing BlockBuilder.

BlockBuilder

public BlockBuilder(boolean optimizing)

Creates a BlockBuilder.

Parameters:

optimizing - Whether to eliminate common sub-expressions

BlockBuilder

public BlockBuilder(boolean optimizing,
                    @Nullable BlockBuilder parent)

Creates a BlockBuilder.

Parameters:

optimizing - Whether to eliminate common sub-expressions

Method Detail

clear

public void clear()

Clears this BlockBuilder.

append

public Expression append(String name,
                         BlockStatement block)

Appends a block to a list of statements and returns an expression (possibly a variable) that represents the result of the newly added block.

append

public Expression append(String name,
                         BlockStatement block,
                         boolean optimize)

Appends an expression to a list of statements, optionally optimizing it to a variable if it is used more than once.

Parameters:

name - Suggested variable name

block - Expression

optimize - Whether to try to optimize by assigning the expression to a variable. Do not do this if the expression has side-effects or a time-dependent value.

append

public Expression append(String name,
                         Expression expression)

Appends an expression to a list of statements, and returns an expression (possibly a variable) that represents the result of the newly added block.

appendIfNotNull

public @PolyNull Expression appendIfNotNull(String name,
                                            @PolyNull Expression expression)

Appends an expression to a list of statements if it is not null, and returns the expression.

append

public Expression append(String name,
                         Expression expression,
                         boolean optimize)

Appends an expression to a list of statements, optionally optimizing if the expression is used more than once.

isSimpleExpression

protected boolean isSimpleExpression(@Nullable Expression expr)

Checks if expression is simple enough to always inline at zero cost.

Parameters:

expr - expression to test

Returns:

true when given expression is safe to always inline

isSafeForReuse

protected boolean isSafeForReuse(DeclarationStatement decl)

addExpressionForReuse

protected void addExpressionForReuse(DeclarationStatement decl)

getComputedExpression

public @Nullable DeclarationStatement getComputedExpression(Expression expr)

Returns the reference to ParameterExpression if given expression was already computed and stored to local variable.

Parameters:

expr - expression to test

Returns:

existing ParameterExpression or null

add

public void add(Statement statement)

add

public void add(Expression expression)

toBlock

public BlockStatement toBlock()

Returns a block consisting of the current list of statements.

createOptimizeShuttle

protected Shuttle createOptimizeShuttle()

Creates a shuttle that will be used during block optimization. Sub-classes might provide more specific optimizations (e.g. partial evaluation).

Returns:

shuttle used to optimize the statements when converting to block

createFinishingOptimizeShuttle

protected Shuttle createFinishingOptimizeShuttle()

Creates a final optimization shuttle. Typically, the visitor will factor out constant expressions.

Returns:

shuttle that is used to finalize the optimization

newName

public String newName(String suggestion)

Creates a name for a new variable, unique within this block.

hasVariable

public boolean hasVariable(String name)

append

public BlockBuilder append(Expression expression)

withRemoveUnused

public BlockBuilder withRemoveUnused(boolean removeUnused)