class TransactionPoolImpl implements TransactionPool {

    @Override
    public synchronized List<Transaction> getPendingTransactions() {
        removeObsoleteTransactions(this.outdatedThreshold, this.outdatedTimeout);
        return Collections.unmodifiableList(pendingTransactions.getTransactions());
    }

    public  TransactionPoolImpl(
            RskSystemProperties config,
            RepositoryLocator repositoryLocator,
            BlockStore blockStore,
            BlockFactory blockFactory,
            EthereumListener listener,
            TransactionExecutorFactory transactionExecutorFactory,
            SignatureCache signatureCache,
            int outdatedThreshold,
            int outdatedTimeout);

}