org.yarnandtail.andhow.compile

Class AndHowCompileProcessor

java.lang.Object

javax.annotation.processing.AbstractProcessor

org.yarnandtail.andhow.compile.AndHowCompileProcessor

All Implemented Interfaces:

Processor

@SupportedAnnotationTypes(value="*")
public class AndHowCompileProcessor
extends AbstractProcessor

This is the central AndHow compilation class, an Annotation Processor. An annotation processor nominally reads annotations as classes are compiled. This class is annotated SupportedAnnotationTypes("*"), allowing it to 'see' all classes as they are compiled. This class then delegates to a 'scanner' class that does deep inspection on compiled code, looking for AndHow Properties.
When an AndHow Property is found in a class, a new PropertyRegistrar class is created, which contains the list of Properties in that class. There is a one-to-one correspondence between user classes that contain AndHow Properties and auto-created PropertyRegistrar classes.
At runtime, AndHow will use the ServiceLoader to discover all instances of PropertyRegistrar on the classpath, thus finding all AndHow Property containing classes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	AndHowCompileProcessor.CauseEffect Match up a causal Element (Basically the compiler representation of a class to be compiled) w/ the Class name that will be registered in a service registry.

Field Summary

Fields inherited from class javax.annotation.processing.AbstractProcessor

processingEnv

Constructor Summary

Constructors

Constructor and Description
AndHowCompileProcessor() A no-arg constructor is required.

Method Summary

Modifier and Type	Method and Description
SourceVersion	getSupportedSourceVersion()
void	init(ProcessingEnvironment processingEnv)
boolean	process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv)
void	writeClassFile(Filer filer, PropertyRegistrarClassGenerator generator, Element causingElement) Writes a new class implementing the PropertyRegistrar interface.
protected void	writeServiceFile(Filer filer, String fullyQualifiedServiceInterfaceName, List<AndHowCompileProcessor.CauseEffect> implementingClasses)

Methods inherited from class javax.annotation.processing.AbstractProcessor

getCompletions, getSupportedAnnotationTypes, getSupportedOptions, isInitialized

Methods inherited from class java.lang.Object

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

Constructor Detail

AndHowCompileProcessor

public AndHowCompileProcessor()

A no-arg constructor is required.

Method Detail

init

public void init(ProcessingEnvironment processingEnv)

Specified by:

init in interface Processor

Overrides:

init in class AbstractProcessor

getSupportedSourceVersion

public SourceVersion getSupportedSourceVersion()

Specified by:

getSupportedSourceVersion in interface Processor

Overrides:

getSupportedSourceVersion in class AbstractProcessor

process

public boolean process(Set<? extends TypeElement> annotations,
                       RoundEnvironment roundEnv)

Specified by:

process in interface Processor

Specified by:

process in class AbstractProcessor

writeClassFile

public void writeClassFile(Filer filer,
                           PropertyRegistrarClassGenerator generator,
                           Element causingElement)
                    throws Exception

Writes a new class implementing the PropertyRegistrar interface. The new class directly corresponds to a user classes containing AndHow Properties and will contain meta data about the properties.

Parameters:

filer - The javac file system representation for writing files.

generator - AndHow class capable of generating source code for this PropertyRegistrar class.

causingElement - A javac Element, which generically refers to any piece of source code such as a keyword, class name, etc.. When a file is written to the filer, a causingElement is recorded as metadata so there is an association between the file and the reason it was written. Likely this is normally used to associate source code line numbers with generated code.

Throws:

Exception - If unable to write (out of disc space?)

writeServiceFile

protected void writeServiceFile(Filer filer,
                                String fullyQualifiedServiceInterfaceName,
                                List<AndHowCompileProcessor.CauseEffect> implementingClasses)
                         throws IOException

Throws:

IOException