private static void writeConfidence(
      Protos.Transaction.Builder txBuilder,
      TransactionConfidence confidence,
      Protos.TransactionConfidence.Builder confidenceBuilder) {
    synchronized (confidence) {
      confidenceBuilder.setType(
          Protos.TransactionConfidence.Type.valueOf(confidence.getConfidenceType().getValue()));
      if (confidence.getConfidenceType() == ConfidenceType.BUILDING) {
        confidenceBuilder.setAppearedAtHeight(confidence.getAppearedAtChainHeight());
        confidenceBuilder.setDepth(confidence.getDepthInBlocks());
      }
      if (confidence.getConfidenceType() == ConfidenceType.DEAD) {
        // Copy in the overriding transaction, if available.
        // (A dead coinbase transaction has no overriding transaction).
        if (confidence.getOverridingTransaction() != null) {
          Sha256Hash overridingHash = confidence.getOverridingTransaction().getHash();
          confidenceBuilder.setOverridingTransaction(hashToByteString(overridingHash));
        }
      }
      TransactionConfidence.Source source = confidence.getSource();
      switch (source) {
        case SELF:
          confidenceBuilder.setSource(Protos.TransactionConfidence.Source.SOURCE_SELF);
          break;
        case NETWORK:
          confidenceBuilder.setSource(Protos.TransactionConfidence.Source.SOURCE_NETWORK);
          break;
        case UNKNOWN:
          // Fall through.
        default:
          confidenceBuilder.setSource(Protos.TransactionConfidence.Source.SOURCE_UNKNOWN);
          break;
      }
    }

    for (ListIterator<PeerAddress> it = confidence.getBroadcastBy(); it.hasNext(); ) {
      PeerAddress address = it.next();
      Protos.PeerAddress proto =
          Protos.PeerAddress.newBuilder()
              .setIpAddress(ByteString.copyFrom(address.getAddr().getAddress()))
              .setPort(address.getPort())
              .setServices(address.getServices().longValue())
              .build();
      confidenceBuilder.addBroadcastBy(proto);
    }
    txBuilder.setConfidence(confidenceBuilder);
  }
  @Test
  public void testAppearedAtChainHeightDepthAndWorkDone() throws Exception {
    // Test the TransactionConfidence appearedAtChainHeight, depth and workDone field are stored.

    BlockChain chain = new BlockChain(params, myWallet, new MemoryBlockStore(params));

    final ArrayList<Transaction> txns = new ArrayList<Transaction>(2);
    myWallet.addEventListener(
        new AbstractWalletEventListener() {
          @Override
          public void onCoinsReceived(
              Wallet wallet, Transaction tx, Coin prevBalance, Coin newBalance) {
            txns.add(tx);
          }
        });

    // Start by building two blocks on top of the genesis block.
    Block b1 = params.getGenesisBlock().createNextBlock(myAddress);
    BigInteger work1 = b1.getWork();
    assertTrue(work1.signum() > 0);

    Block b2 = b1.createNextBlock(myAddress);
    BigInteger work2 = b2.getWork();
    assertTrue(work2.signum() > 0);

    assertTrue(chain.add(b1));
    assertTrue(chain.add(b2));

    // We now have the following chain:
    //     genesis -> b1 -> b2

    // Check the transaction confidence levels are correct before wallet roundtrip.
    Threading.waitForUserCode();
    assertEquals(2, txns.size());

    TransactionConfidence confidence0 = txns.get(0).getConfidence();
    TransactionConfidence confidence1 = txns.get(1).getConfidence();

    assertEquals(1, confidence0.getAppearedAtChainHeight());
    assertEquals(2, confidence1.getAppearedAtChainHeight());

    assertEquals(2, confidence0.getDepthInBlocks());
    assertEquals(1, confidence1.getDepthInBlocks());

    // Roundtrip the wallet and check it has stored the depth and workDone.
    Wallet rebornWallet = roundTrip(myWallet);

    Set<Transaction> rebornTxns = rebornWallet.getTransactions(false);
    assertEquals(2, rebornTxns.size());

    // The transactions are not guaranteed to be in the same order so sort them to be in chain
    // height order if required.
    Iterator<Transaction> it = rebornTxns.iterator();
    Transaction txA = it.next();
    Transaction txB = it.next();

    Transaction rebornTx0, rebornTx1;
    if (txA.getConfidence().getAppearedAtChainHeight() == 1) {
      rebornTx0 = txA;
      rebornTx1 = txB;
    } else {
      rebornTx0 = txB;
      rebornTx1 = txA;
    }

    TransactionConfidence rebornConfidence0 = rebornTx0.getConfidence();
    TransactionConfidence rebornConfidence1 = rebornTx1.getConfidence();

    assertEquals(1, rebornConfidence0.getAppearedAtChainHeight());
    assertEquals(2, rebornConfidence1.getAppearedAtChainHeight());

    assertEquals(2, rebornConfidence0.getDepthInBlocks());
    assertEquals(1, rebornConfidence1.getDepthInBlocks());
  }