class WalletManager {

    public List<String> getAddressList() {
        if (mWalletList == null || mWalletList.isEmpty()) {
            return new ArrayList<>();
        }
        return Flowable.fromIterable(mWalletList)
                .map(new Function<Wallet, String>() {
                    @Override
                    public String apply(Wallet walletEntity) throws Exception {
                        return walletEntity.getPrefixAddress();
                    }
                }).collect(new Callable<List<String>>() {
                    @Override
                    public List<String> call() throws Exception {
                        return new ArrayList<>();
                    }
                }, new BiConsumer<List<String>, String>() {
                    @Override
                    public void accept(List<String> strings, String s) throws Exception {
                        strings.add(s);
                    }
                }).blockingGet();
    }

    private  WalletManager();

}