a class that represents a long value that is restored from @{SharedPreferences}. It is thread safe.

PersistentLong,java

package com.sensorberg.sdk.internal;

import android.content.SharedPreferences;

import com.sensorberg.sdk.Constants;

/**
 * a class that represents a long value that is restored from @{SharedPreferences}. It is thread safe.
 */
public class PersistentLong {
    private final SharedPreferences settingsSharedPrefs;
    private long postToServiceCounter;
    private final Object postToServiceCounterMonitor = new Object();

    public PersistentLong(SharedPreferences settingsSharedPrefs) {
        this.settingsSharedPrefs = settingsSharedPrefs;
        postToServiceCounter = settingsSharedPrefs.getLong(Constants.SharedPreferencesKeys.Platform.POST_TO_SERVICE_COUNTER, 0);
    }

    /**
     * get the next value, +1 bigger than the last.
     * @return the next value, unique, thread safe unique
     */
    public long next(){
        synchronized (postToServiceCounterMonitor) {
            postToServiceCounter++;
            settingsSharedPrefs.edit()
                    .putLong(Constants.SharedPreferencesKeys.Platform.POST_TO_SERVICE_COUNTER, postToServiceCounter)
                    .apply();
            return postToServiceCounter;
        }
    }
}