egordorichev/LastTry

package org.egordorichev.lasttry.injection;

import com.google.common.collect.Maps;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class ContextImpl implements Context{
    private static final Logger logger = LoggerFactory.getLogger(ContextImpl.class);

    private final Map<Class<?> , Provider> providers = Maps.newHashMap();

    private Context parent;

    public ContextImpl(Context context){
        this.parent = context;
    }

    public ContextImpl(){

    }

    public void setParent(Context context){
        this.parent = context;
    }

    public <T> void bindProvider(Class<? extends T> classz,Provider<T> provider) {
        providers.put(classz,provider);
    }

    public <T> T bindInstance(Class<? extends T> classz, T object){
        bindProvider(classz,() -> object);
        return object;
    }

    @Override
    public <T> T get(Class<? extends T> requestedType) {
        Provider<T> provider = providers.get(requestedType);
        if(provider == null) {
            if(parent == null) {
                logger.error("can't find type mapping for {}", requestedType);
                return null;
            }
            return parent.get(requestedType);
        }
        return provider.get();
    }
}