sirius.tagliatelle.emitter

Class Emitter

java.lang.Object

sirius.tagliatelle.emitter.Emitter

Direct Known Subclasses:

BlockEmitter, CompositeEmitter, ConditionalEmitter, ConstantEmitter, DynamicInvokeTemplateEmitter, ExpressionEmitter, ExtraBlockEmitter, InlineTemplateEmitter, InvokeTemplateEmitter, LoopEmitter, PushLocalEmitter, RawEmitter

public abstract class Emitter
extends Object

Represents a part of a Template which generates text output when the template is rendered.

Field Summary

Fields

Modifier and Type	Field and Description
protected parsii.tokenizer.Position	startOfBlock Contains the position in the source file where this emitter was created.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Emitter(parsii.tokenizer.Position startOfBlock) Contains a new emitter with the given position.

Method Summary

Modifier and Type	Method and Description
abstract Emitter	copy() Creates a deep copy of this emitter.
void	emit(LocalRenderContext context) Procudes the text output into the given context.
protected abstract void	emitToContext(LocalRenderContext context) Actually produces the output while relying on the caller to properly handle any exception.
parsii.tokenizer.Position	getStartOfBlock() Returns the start position within the source file.
abstract Emitter	propagateVisitor(EmitterVisitor visitor) Invokes the visitor on all sub emitters and on this emitter itself.
abstract Emitter	reduce() Performs static optimizations at compile time.
abstract void	visitExpressions(Function<parsii.tokenizer.Position,ExpressionVisitor> visitor) Visits all expressions contained in this emitter or its children.

Methods inherited from class java.lang.Object

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

Field Detail

startOfBlock

protected parsii.tokenizer.Position startOfBlock

Contains the position in the source file where this emitter was created.

Constructor Detail

Emitter

protected Emitter(@Nonnull
                  parsii.tokenizer.Position startOfBlock)

Contains a new emitter with the given position.

Parameters:

startOfBlock - the start position where the emitter was created

Method Detail

emit

public void emit(@Nonnull
                 LocalRenderContext context)
          throws RenderException

Procudes the text output into the given context.

Parameters:

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

Throws:

RenderException - in case of any exception which occurs during rendering

emitToContext

protected abstract void emitToContext(@Nonnull
                                      LocalRenderContext context)
                               throws Exception

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

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

getStartOfBlock

@Nonnull
public parsii.tokenizer.Position getStartOfBlock()

Returns the start position within the source file.

Returns:

the start of the definition which created this emitter

copy

@Nonnull
public abstract Emitter copy()

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.

Returns:

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

reduce

@Nonnull
public abstract Emitter reduce()

Performs static optimizations at compile time.

Certain emitters can perform optimizations (evaluate constant expressions, combine constant outputs etc.) to create more efficient templates. This is especially important when a template is inlined, as this most probably provides a higher level of optimizations.

Returns:

a reduced version of this emitter of the emitter itself, if no further optimizations are possible

propagateVisitor

@Nonnull
public abstract Emitter propagateVisitor(@Nonnull
                                                  EmitterVisitor visitor)

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

Parameters:

visitor - the visitor to invoke

Returns:

the resulting emitter returned by the visitor

visitExpressions

public abstract void visitExpressions(@Nonnull
                                      Function<parsii.tokenizer.Position,ExpressionVisitor> visitor)

Visits all expressions contained in this emitter or its children.

Parameters:

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