android-utils/luticateutils/src/main/java/com/luticate/utils/business/LuPromise.java

package com.luticate.utils.business;

import com.luticate.utils.dbo.LuPromiseError;

import java.util.List;
import java.util.Vector;

/**
 *
 * Created by robin on 11/27/15.
 */
public class LuPromise<T> {

    public enum LuPromiseStatus {
        Running,
        Resolved,
        Failed
    }

    private List<LuConsumer<T>> _onSuccess = new Vector<>();

    private List<LuConsumer<LuPromiseError>> _onFailed = new Vector<>();

    protected LuPromiseStatus _status = LuPromiseStatus.Running;

    protected T _data = null;

    protected LuPromiseError _error = null;

    public LuPromiseStatus getStatus()
    {
        return _status;
    }

    public T getData()
    {
        return _data;
    }

    public LuPromiseError getError()
    {
        return _error;
    }

    public LuPromise<T> then(LuConsumer<T> onSuccess, LuConsumer<LuPromiseError> onFailed)
    {
        _onFailed.add(onFailed);
        if (_status == LuPromiseStatus.Failed) {
            if (onFailed != null) {
                onFailed.execute(_error);
            }
        }
        return then(onSuccess);
    }

    public LuPromise<T> then(LuConsumer<T> onSuccess)
    {
        _onSuccess.add(onSuccess);
        if (_status == LuPromiseStatus.Resolved) {
            if (onSuccess != null) {
                onSuccess.execute(_data);
            }
        }
        return this;
    }

    public LuPromise<T> resolve(T data)
    {
        if (_status == LuPromiseStatus.Running) {
            _data = data;
            _error = null;
            _status = LuPromiseStatus.Resolved;
            onSuccess();
        }
        return this;
    }

    public LuPromise<T> reject(LuPromiseError error)
    {
        if (_status == LuPromiseStatus.Running) {
            _data = null;
            _error = error;
            _status = LuPromiseStatus.Failed;
            onFailed();
        }
        return this;
    }

    public <T2> LuPromise<T2> map(final LuConverter<T, T2> converter)
    {
        final LuPromise<T2> promise = new LuPromise<>();
        then(new LuConsumer<T>() {
            @Override
            public void execute(T data) {
                promise.resolve(converter.convert(data));
            }
        }, getRejectConsumer());
        return promise;
    }

    public LuConsumer<LuPromiseError> getRejectConsumer()
    {
        return new LuConsumer<LuPromiseError>() {
            @Override
            public void execute(LuPromiseError error) {
                reject(error);
            }
        };
    }

    protected void onSuccess()
    {
        for (LuConsumer<T> c : _onSuccess) {
            if (c != null) {
                c.execute(_data);
            }
        }
    }

    protected void onFailed()
    {
        for (LuConsumer<LuPromiseError> c : _onFailed) {
            if (c != null) {
                c.execute(_error);
            }
        }
    }
}