Merge "Create @StringDef for the PREFIX_* values"

import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;

import android.annotation.NonNull;

import android.annotation.StringDef;

import android.annotation.SystemApi;

import android.net.NetworkIdentity;

import android.net.NetworkStatsCollection;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.net.ProtocolException;

import java.util.ArrayList;

import java.util.HashMap;

     */

    public static final String PREFIX_UID_TAG = "uid_tag";

    /** @hide */

    @StringDef(prefix = {"PREFIX_"}, value = {

        PREFIX_XT,

        PREFIX_UID,

        PREFIX_UID_TAG,

    })

    @Retention(RetentionPolicy.SOURCE)

    public @interface Prefix {}

    private static final HashMap<String, String> sPrefixLegacyFileNameMap =

            new HashMap<String, String>() {{

                put(PREFIX_XT, "netstats_xt.bin");

    // Get /data/system/netstats_*.bin legacy files. Does not check for existence.

    @NonNull

    private static File getLegacyBinFileForPrefix(@NonNull String prefix) {

    private static File getLegacyBinFileForPrefix(@NonNull @Prefix String prefix) {

        return new File(getPlatformSystemDir(), sPrefixLegacyFileNameMap.get(prefix));

    }

    // List /data/system/netstats/[xt|uid|uid_tag].<start>-<end> legacy files.

    @NonNull

    private static ArrayList<File> getPlatformFileListForPrefix(@NonNull String prefix) {

    private static ArrayList<File> getPlatformFileListForPrefix(@NonNull @Prefix String prefix) {

        final ArrayList<File> list = new ArrayList<>();

        final File platformFiles = new File(getPlatformBaseDir(), "netstats");

        if (platformFiles.exists()) {

     */

    @NonNull

    public static NetworkStatsCollection readPlatformCollection(

            @NonNull String prefix, long bucketDuration) throws IOException {

            @NonNull @Prefix String prefix, long bucketDuration) throws IOException {

        final NetworkStatsCollection.Builder builder =

                new NetworkStatsCollection.Builder(bucketDuration);