sourceafIoc::IocService.fan

**
** Wraps an afIoc `Registry` instance as Fantom service.
** 
** A Service for all Services!
** 
const class IocService : Service {
    private static const Log        log         := Utils.getLog(IocService#)
    private const ThreadStash       stash       := ThreadStash(IocService#.name)
    private const ConcurrentState   conState    := ConcurrentState(IocServiceState#)

    private Type[] moduleTypes {
        get { stash["moduleTypes"] }
        set { stash["moduleTypes"] = it }
    }

    private Bool dependencies {
        get { stash["dependencies"] }
        set { stash["dependencies"] = it }
    }

    private Pod dependencyPod {
        get { stash["dependencyPod"] }
        set { stash["dependencyPod"] = it }
    }

    private Bool indexProps {
        get { stash["indexProps"] }
        set { stash["indexProps"] = it }
    }

    private Err? startErr {
        get { stash["startErr"] }
        set { stash["startErr"] = it }
    }

    Registry? registry {
        // ensure the registry is shared amongst all threads 
        get { 
            // rethrow any errs that occurred on startup 
            // see http://fantom.org/sidewalk/topic/2133
            if (startErr != null)
                throw startErr
            return conState.getState |IocServiceState state->Obj?| { return state.registry } 
        }
        private set { reg := it; conState.withState |IocServiceState state| { state.registry = reg} }
    }


    // ---- Public Builder Methods ---------------------------------------------------------------- 

    new make(Type[] moduleTypes := [,]) {
        this.moduleTypes    = moduleTypes
        this.indexProps     = false
        this.dependencies   = false
    }
    
    ** Convenience for `RegistryBuilder.addModulesFromDependencies`
    This addModulesFromDependencies(Pod dependenciesOf) {
        checkServiceNotStarted
        dependencies = true
        dependencyPod = dependenciesOf
        return this
    }

    ** Convenience for `RegistryBuilder.addModulesFromIndexProperties`
    This addModulesFromIndexProperties() {
        checkServiceNotStarted
        indexProps = true
        return this
    }

    ** Convenience for `RegistryBuilder.addModules`
    This addModules(Type[] moduleTypes) {
        checkServiceNotStarted
        this.moduleTypes = this.moduleTypes.addAll(moduleTypes)
        return this
    }


    // ---- Service Lifecycle Methods ------------------------------------------------------------- 

    ** Builds and starts up the registry.
    ** See `RegistryBuilder.build`.
    ** See `Registry.startup`.
    override Void onStart() {
        checkServiceNotStarted
        log.info("Starting IOC...");
    
        try {
            regBuilder := RegistryBuilder()
            
            if (indexProps)
                regBuilder.addModulesFromIndexProperties
            
            if (dependencies)
                regBuilder.addModulesFromDependencies(dependencyPod, true)
            
            regBuilder.addModules(moduleTypes)
            
            registry := regBuilder.build
            
            // assign registry now, so it may be looked up (via this service) during startup
            conState.withState |IocServiceState state| {
                state.registry = registry
            }

            registry.startup
            
        } catch (Err e) {
            log.err("Err starting IOC", e)
            
            // keep the err so we can rethrow later (as 'Service.start()' swallows it)
            // see http://fantom.org/sidewalk/topic/2133
            startErr = e
            
            // re throw so Fantom doesn't start the service (since Fantom 1.0.65)
            // see http://fantom.org/sidewalk/topic/2133
            throw e
        }
    }

    ** Shuts down the registry.
    ** See `Registry.shutdown`.
    override Void onStop() {
        if (registry == null) {
            log.info("Registry already stopped.")
            return
        }
        log.info("Stopping IOC...");
        registry.shutdown
        registry = null
    }

    // ---- Registry Methods ----------------------------------------------------------------------
    
    ** Convenience for `Registry.serviceById`
    Obj serviceById(Str serviceId) {
        checkServiceStarted
        return registry.serviceById(serviceId)
    }
    
    ** Convenience for `Registry.dependencyByType`
    Obj dependencyByType(Type serviceType) {
        checkServiceStarted
        return registry.dependencyByType(serviceType)
    }

    ** Convenience for `Registry.autobuild`
    Obj autobuild(Type type) {
        checkServiceStarted
        return registry.autobuild(type)
    }
    
    ** Convenience for `Registry.injectIntoFields`
    Obj injectIntoFields(Obj service) {
        checkServiceStarted
        return registry.injectIntoFields(service)
    }   


    // ---- Private Methods -----------------------------------------------------------------------

    private Void checkServiceStarted() {
        if (registry == null)
            throw IocErr(IocMessages.serviceNotStarted)
    }

    private Void checkServiceNotStarted() {
        if (registry != null)
            throw IocErr(IocMessages.serviceStarted)
    }
    
}

internal class IocServiceState {
    Registry? registry
}