custom base adapter

import android.os.Handler;
import android.support.annotation.IntDef;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.concurrent.atomic.AtomicBoolean;

import controllers.constants.CallBackConstants;
import controllers.listeners.ProcessedResult;

//Custom adapter with states and endless scroll on bottom rick
public class StatesRecyclerViewAdapter extends RecyclerViewAdapterWrapper {
    private final View vLoadingView;
    private final View vEmptyView;
    private final View vErrorView;

    @IntDef({STATE_NORMAL, STATE_EMPTY, STATE_ERROR,STATE_ENDLESS})
    @Retention(RetentionPolicy.SOURCE)
    public @interface State {
    }

    public static final int STATE_NORMAL = 0;
    // public static final int STATE_LOADING = 1;
    public static final int STATE_EMPTY = 2;
    public static final int STATE_ERROR = 3;
    public static final int STATE_ENDLESS = 4;

    //public static final int TYPE_LOADING = 1000;
    private static final int TYPE_EMPTY = 1001;
    private static final int TYPE_ERROR = 1002;
    private static final int TYPE_ENDLESS= 1003;

    private AtomicBoolean keepOnAppending;
    private AtomicBoolean dataPending;
    private ProcessedResult requestToLoadMoreListener;

    @State
    private int state = STATE_NORMAL;

    private StatesRecyclerViewAdapter(@NonNull RecyclerView.Adapter wrapped, @Nullable View vLoadingView, @Nullable View emptyView, @Nullable View errorView,
                                      ProcessedResult requestToLoadMoreListener, boolean keepOnAppending) {
        super(wrapped);

        this.vEmptyView = emptyView;
        this.vErrorView = errorView;
        this.vLoadingView=vLoadingView;
        this.requestToLoadMoreListener = requestToLoadMoreListener;

        this.keepOnAppending = new AtomicBoolean(keepOnAppending);
        dataPending = new AtomicBoolean(false);
    }

    public StatesRecyclerViewAdapter(@NonNull RecyclerView.Adapter wrapped, @Nullable View vLoadingView, @Nullable View emptyView, @Nullable View errorView
            , ProcessedResult requestToLoadMoreListener) {
        this(wrapped,vLoadingView,emptyView,errorView, requestToLoadMoreListener, true);
    }

    private void stopAppending() {
        setKeepOnAppending(false);
    }

    /**
     * Let the adapter know that data is load and ready to view.
     *
     * @param keepOnAppending whether the adapter should request to load more when scrolling to the bottom.
     */
    public void onDataReady(boolean keepOnAppending) {
        dataPending.set(false);
        setKeepOnAppending(keepOnAppending);
    }

    private void setKeepOnAppending(boolean newValue) {
        keepOnAppending.set(newValue);
        if(STATE_ENDLESS==getState())
            setState(STATE_NORMAL);
        else
            notifyWrapperAdapter();
    }

    private void notifyWrapperAdapter()
    {
        new Handler().post(new Runnable() {
            @Override
            public void run(){
                //change adapter contents
                getWrappedAdapter().notifyDataSetChanged();
            }
        });
    }

    /**
     *Restart
     */
    public void restartAppending() {
        dataPending.set(false);
        setKeepOnAppending(true);
    }

    @State
    public int getState() {
        return state;
    }

    public void setState(@State int state) {
        if(state==getState())
            return;
        this.state = state;
        notifyWrapperAdapter();
        new Handler().post(new Runnable() {
            @Override
            public void run(){
                notifyDataSetChanged();
            }
        });
    }

    @Override
    public int getItemCount() {
        switch (state) {
            case STATE_EMPTY:
            case STATE_ERROR: {
                dataPending.set(false);
                return 1;
            }
            case STATE_ENDLESS:
            default:
                return super.getItemCount() + (keepOnAppending.get() ? 1 : 0);
        }
    }

    @Override
    public int getItemViewType(int position) {
        switch (state) {
            case STATE_EMPTY:
                return TYPE_EMPTY;
            case STATE_ERROR:
                return TYPE_ERROR;
            case STATE_ENDLESS:
                return TYPE_ENDLESS;
            default: {
                if (position == getWrappedAdapter().getItemCount())
                    return TYPE_ENDLESS;
                return super.getItemViewType(position);
            }
        }
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        switch (viewType) {
            case TYPE_EMPTY:
                return new SimpleViewHolder(vEmptyView);
            case TYPE_ERROR:
                return new SimpleViewHolder(vErrorView);
            case TYPE_ENDLESS:
                return new SimpleViewHolder(vLoadingView);
            default:
                return super.onCreateViewHolder(parent, viewType);
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        switch (state) {
            case STATE_EMPTY:
            case STATE_ERROR:
                onBindCViewHolder(holder, position);
                return;
            case STATE_ENDLESS:
                endlessRecycler();
                return;
            default:
                if (getItemViewType(position) == TYPE_ENDLESS)
                    endlessRecycler();
                else
                    super.onBindViewHolder(holder, position);
        }
    }

    private void endlessRecycler()
    {
        if (!dataPending.get()) {

            dataPending.set(true);
            requestToLoadMoreListener.processedResult(null, CallBackConstants.LOAD_MORE_METHOD);
        }
    }

    private void onBindCViewHolder(RecyclerView.ViewHolder holder, int position) {
    }

    private static class SimpleViewHolder extends RecyclerView.ViewHolder {
        SimpleViewHolder(View itemView) {
            super(itemView);
        }
    }


public interface ProcessedResult {
    <IResponse,IMethod>void processedResult(IResponse iResponse, IMethod iMethod);
}
}