sirius.tagliatelle.emitter

Class ConditionalEmitter

java.lang.Object

sirius.tagliatelle.emitter.Emitter

sirius.tagliatelle.emitter.ConditionalEmitter

public class ConditionalEmitter
extends Emitter

Represents a conditional block which is only emitted if a given expression evaluates to true.

A conditional block can either be defined via the built-in tag <i:if> or via an if statement.

See Also:

IfTag

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression	conditionExpression
protected Emitter	whenFalse
protected Emitter	whenTrue

Fields inherited from class sirius.tagliatelle.emitter.Emitter

startOfBlock

Constructor Summary

Constructors

Constructor and Description
ConditionalEmitter(parsii.tokenizer.Position startOfBlock) Creates a new emitter for the given position.

Method Summary

Modifier and Type	Method and Description
Emitter	copy() Creates a deep copy of this emitter.
protected void	emitToContext(LocalRenderContext context) Actually produces the output while relying on the caller to properly handle any exception.
Emitter	propagateVisitor(EmitterVisitor visitor) Invokes the visitor on all sub emitters and on this emitter itself.
Emitter	reduce() Reduces the condition as well as the true and false blocks.
void	setConditionExpression(Expression conditionExpression) Specifies the expression to evaluate to determine which block to emit.
void	setWhenFalse(Emitter whenFalse) Specifies the block to emit if the condition evaluates to false.
void	setWhenTrue(Emitter whenTrue) Specifies the block to emit if the condition evaluates to true.
String	toString()
void	visitExpressions(Function<parsii.tokenizer.Position,ExpressionVisitor> visitorSupplier) Visits all expressions contained in this emitter or its children.

Methods inherited from class sirius.tagliatelle.emitter.Emitter

emit, getStartOfBlock

Methods inherited from class java.lang.Object

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

Field Detail

conditionExpression

protected Expression conditionExpression

whenTrue

protected Emitter whenTrue

whenFalse

protected Emitter whenFalse

Constructor Detail

ConditionalEmitter

public ConditionalEmitter(parsii.tokenizer.Position startOfBlock)

Creates a new emitter for the given position.

Parameters:

startOfBlock - the position where the conditional block was defined.

Method Detail

emitToContext

protected void emitToContext(LocalRenderContext context)
                      throws Exception

Description copied from class: Emitter

Actually produces the output while relying on the caller to properly handle any exception.

Specified by:

emitToContext in class Emitter

Parameters:

context - the render context which provides access to the local and global environment and also the target for the generated text

Throws:

Exception - all thrown exceptions are caught and converted into a RenderException

setConditionExpression

public void setConditionExpression(Expression conditionExpression)

Specifies the expression to evaluate to determine which block to emit.

Parameters:

conditionExpression - the condition as expression

setWhenTrue

public void setWhenTrue(Emitter whenTrue)

Specifies the block to emit if the condition evaluates to true.

Parameters:

whenTrue - the block to emit when the condition is true

setWhenFalse

public void setWhenFalse(Emitter whenFalse)

Specifies the block to emit if the condition evaluates to false.

Parameters:

whenFalse - the block to emit when the condition is false

copy

public Emitter copy()

Description copied from class: Emitter

Creates a deep copy of this emitter.

When templates are inlined, the parameters are propagated and constant expressions and conditions are evaluated at compile time. This yields faster and more efficient templates. In order to perform these optimizations, we need a copy of the template and all its emitters which can safely be modified.

Specified by:

copy in class Emitter

Returns:

a deep copy of this emitter, which can safely be modified without changing this emitter

reduce

public Emitter reduce()

Reduces the condition as well as the true and false blocks.

If the condition becomes constant, the emitter is reduced the the repective true or false block.

Specified by:

reduce in class Emitter

Returns:

either the emitter itself or, if the condition is constant, the true or false block

propagateVisitor

public Emitter propagateVisitor(EmitterVisitor visitor)

Description copied from class: Emitter

Invokes the visitor on all sub emitters and on this emitter itself.

Specified by:

propagateVisitor in class Emitter

Parameters:

visitor - the visitor to invoke

Returns:

the resulting emitter returned by the visitor

visitExpressions

public void visitExpressions(Function<parsii.tokenizer.Position,ExpressionVisitor> visitorSupplier)

Description copied from class: Emitter

Visits all expressions contained in this emitter or its children.

Specified by:

visitExpressions in class Emitter

Parameters:

visitorSupplier - a function which generates an ExpressionVisitor while supplying the current position (for improved error messages).

toString

public String toString()

Overrides:

toString in class Object