TimeoutData.java

package ru.alexfitness.data.core.dto;

import android.support.annotation.Nullable;

import org.jetbrains.annotations.Contract;

public class TimeoutData<T> {
    @Nullable
    private final T data;
    private final long timeoutMilliseconds;
    private final long startTime;

    public TimeoutData(@Nullable T data, long timeoutMilliseconds) {
        this.data = data;
        this.timeoutMilliseconds = timeoutMilliseconds;
        startTime = getCurrentMilliseconds();
    }

    @Contract("null -> false")
    public static boolean isActual(@Nullable TimeoutData timeoutData) {
        return timeoutData != null && !timeoutData.isTimedOut() && timeoutData.data != null;
    }

    public static <T> TimeoutData<T> createNotActual() {
        return new TimeoutData<>(null, 0);
    }

    public T getData() throws NullPointerException {
        if (data == null) {
            throw new NullPointerException("data is null");
        }
        return data;
    }

    private boolean isTimedOut() {
        return getCurrentMilliseconds() > startTime + timeoutMilliseconds;
    }

    private long getCurrentMilliseconds() {
        return System.currentTimeMillis();
    }
}