package net.sf.dobo.guice;

import com.google.inject.Provider;

import net.sf.dobo.Context;
import net.sf.dobo.Dobo;

import java.lang.annotation.Annotation;


/**
 * Google guice provider
 *
 * @author arif
 * @version 1.0
 *
 * @param <T> Type of Provider
 */
public class DoboProvider<T> implements Provider<T> {
    /**
     * Context Implementation Object
     */
    private Object contextImplementationObject;

    /**
     * The context
     */
    private Class<?extends Annotation> context;

    /**
     * Flag indicating bean is singleton
     */
    private boolean singleton = false;

    /**
     * The instance of proxy
     */
    private T instance = null;

    /**
     * The Factory Constructor
     * @param contextImplementationObject
     * @param context
     */
    public DoboProvider(final Object contextImplementationObject,
        final Class<?extends Annotation> context) {
        this.contextImplementationObject = contextImplementationObject;
        this.context = context;
        Dobo.check(contextImplementationObject.getClass());
    }

    /**
     * @see org.springframework.beans.factory.FactoryBean#getObject()
     */
    @SuppressWarnings("unchecked")
    public T get() {
        synchronized (this) {
            if (singleton && (instance == null)) {
                instance = (T) Dobo.instantiate(contextImplementationObject, context);

                return instance;
            } else {
                return (T) Dobo.instantiate(contextImplementationObject, context);
            }
        }
    }

    /**
     * @see org.springframework.beans.factory.FactoryBean#getObjectType()
     */
    public Class<?> getObjectType() {
        return context.getAnnotation(Context.class).value();
    }

    /**
     * @see org.springframework.beans.factory.FactoryBean#isSingleton()
     */
    public boolean isSingleton() {
        return singleton;
    }

    /**
     * Set to indicate object is singleton
     *
     * @param singleton
     */
    public DoboProvider<T> setSingleton(final boolean singleton) {
        this.singleton = singleton;

        return this;
    }
}