Rollout conditional signature serialization to remaining transaction types.

Also added/corrected some JavaDoc.

src/qora/block/Block.java

@@ -5,7 +5,6 @@ import static java.util.stream.Collectors.toMap;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
-import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -463,10 +462,10 @@ public class Block {
 	 * <p>
 	 * Performs various tests like checking for parent block, correct block timestamp, version, generating balance, etc.
 	 * <p>
-	 * Checks block's transactions using an HSQLDB "SAVEPOINT" and hence needs to be called within an ongoing SQL Transaction.
+	 * Checks block's transactions by testing their validity then processing them.<br>
+	 * Hence <b>calls repository.discardChanges()</b> before returning.
 	 * 
-	 * @return true if block is valid, false otherwise.
-	 * @throws SQLException
+	 * @return ValidationResult.OK if block is valid, or some other ValidationResult otherwise.
 	 * @throws DataException
 	 */
 	public ValidationResult isValid() throws DataException {
@@ -561,13 +560,13 @@ public class Block {
 		} catch (DataException e) {
 			return ValidationResult.TRANSACTION_TIMESTAMP_INVALID;
 		} finally {
-			// Revert back to savepoint
+			// Discard changes to repository made by test-processing transactions above
 			try {
 				this.repository.discardChanges();
 			} catch (DataException e) {
 				/*
-				 * Rollback failure most likely due to prior DataException, so catch rollback's DataException and discard. A "return false" in try-block will
-				 * still return false, prior DataException propagates to caller and successful completion of try-block continues on after rollback.
+				 * Discard failure most likely due to prior DataException, so catch discardChanges' DataException and discard.
+				 * Prior DataException propagates to caller. Successful completion of try-block continues on after discard.
 				 */
 			}
 		}

src/qora/block/BlockChain.java

@@ -17,29 +17,17 @@ import repository.RepositoryManager;
  */
 public class BlockChain {
 
-	/**
-	 * Minimum Qora balance.
-	 */
+	/** Minimum Qora balance for use in calculations. */
 	public static final BigDecimal MIN_BALANCE = BigDecimal.valueOf(1L).setScale(8);
-	/**
-	 * Maximum Qora balance.
-	 */
+	/** Maximum Qora balance. */
 	public static final BigDecimal MAX_BALANCE = BigDecimal.valueOf(10_000_000_000L).setScale(8);
-	/**
-	 * Number of blocks between recalculating block's generating balance.
-	 */
+	/** Number of blocks between recalculating block's generating balance. */
 	public static final int BLOCK_RETARGET_INTERVAL = 10;
-	/**
-	 * Minimum target time between blocks, in seconds.
-	 */
+	/** Minimum target time between blocks, in seconds. */
 	public static final long MIN_BLOCK_TIME = 60;
-	/**
-	 * Maximum target time between blocks, in seconds.
-	 */
+	/** Maximum target time between blocks, in seconds. */
 	public static final long MAX_BLOCK_TIME = 300;
-	/**
-	 * Maximum acceptable timestamp disagreement offset in milliseconds.
-	 */
+	/** Maximum acceptable timestamp disagreement offset in milliseconds. */
 	public static final long BLOCK_TIMESTAMP_MARGIN = 500L;
 
 	// Various release timestamps / block heights

src/qora/transaction/Transaction.java

@@ -62,7 +62,7 @@ public abstract class Transaction {
 		}
 	}
 
-	// Minimum fee
+	/** Minimum fee for a transaction */
 	public static final BigDecimal MINIMUM_FEE = BigDecimal.ONE;
 
 	// Cached info to make transaction processing faster
@@ -75,11 +75,26 @@ public abstract class Transaction {
 
 	// Constructors
 
+	/**
+	 * Basic constructor for use by subclasses.
+	 * 
+	 * @param repository
+	 * @param transactionData
+	 */
 	protected Transaction(Repository repository, TransactionData transactionData) {
 		this.repository = repository;
 		this.transactionData = transactionData;
 	}
 
+	/**
+	 * Returns subclass of Transaction constructed using passed transaction data.
+	 * <p>
+	 * Uses transaction-type in transaction data to call relevant subclass constructor.
+	 * 
+	 * @param repository
+	 * @param transactionData
+	 * @return a Transaction subclass, or null if a transaction couldn't be determined/built from passed data
+	 */
 	public static Transaction fromData(Repository repository, TransactionData transactionData) {
 		switch (transactionData.getType()) {
 			case GENESIS:

src/qora/voting/Poll.java

@@ -13,13 +13,19 @@ public class Poll {
 
 	// Constructors
 
+	/**
+	 * Construct Poll business object using poll data.
+	 * 
+	 * @param repository
+	 * @param pollData
+	 */
 	public Poll(Repository repository, PollData pollData) {
 		this.repository = repository;
 		this.pollData = pollData;
 	}
 
 	/**
-	 * Create Poll business object using info from create poll transaction.
+	 * Construct Poll business object using info from create poll transaction.
 	 * 
 	 * @param repository
 	 * @param createPollTransactionData
@@ -27,9 +33,17 @@ public class Poll {
 	public Poll(Repository repository, CreatePollTransactionData createPollTransactionData) {
 		this.repository = repository;
 		this.pollData = new PollData(createPollTransactionData.getCreatorPublicKey(), createPollTransactionData.getOwner(),
-				createPollTransactionData.getPollName(), createPollTransactionData.getDescription(), createPollTransactionData.getPollOptions(), createPollTransactionData.getTimestamp());
+				createPollTransactionData.getPollName(), createPollTransactionData.getDescription(), createPollTransactionData.getPollOptions(),
+				createPollTransactionData.getTimestamp());
 	}
 
+	/**
+	 * Construct Poll business object using existing poll from repository, identified by pollName.
+	 * 
+	 * @param repository
+	 * @param pollName
+	 * @throws DataException
+	 */
 	public Poll(Repository repository, String pollName) throws DataException {
 		this.repository = repository;
 		this.pollData = this.repository.getVotingRepository().fromPollName(pollName);
@@ -46,6 +60,13 @@ public class Poll {
 		this.repository.getVotingRepository().save(this.pollData);
 	}
 
+	/**
+	 * "Unpublish" poll, removing it from blockchain.
+	 * <p>
+	 * Typically used when orphaning create poll transaction.
+	 * 
+	 * @throws DataException
+	 */
 	public void unpublish() throws DataException {
 		this.repository.getVotingRepository().delete(this.pollData.getPollName());
 	}

src/transform/transaction/CancelOrderTransactionTransformer.java

@@ -66,7 +66,9 @@ public class CancelOrderTransactionTransformer extends TransactionTransformer {
 			bytes.write(cancelOrderTransactionData.getOrderId());
 
 			Serialization.serializeBigDecimal(bytes, cancelOrderTransactionData.getFee());
-			bytes.write(cancelOrderTransactionData.getSignature());
+
+			if (cancelOrderTransactionData.getSignature() != null)
+				bytes.write(cancelOrderTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {

src/transform/transaction/CreateOrderTransactionTransformer.java

@@ -71,7 +71,9 @@ public class CreateOrderTransactionTransformer extends TransactionTransformer {
 			Serialization.serializeBigDecimal(bytes, createOrderTransactionData.getPrice(), AMOUNT_LENGTH);
 
 			Serialization.serializeBigDecimal(bytes, createOrderTransactionData.getFee());
-			bytes.write(createOrderTransactionData.getSignature());
+
+			if (createOrderTransactionData.getSignature() != null)
+				bytes.write(createOrderTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {

src/transform/transaction/IssueAssetTransactionTransformer.java

@@ -86,7 +86,9 @@ public class IssueAssetTransactionTransformer extends TransactionTransformer {
 			bytes.write((byte) (issueAssetTransactionData.getIsDivisible() ? 1 : 0));
 
 			Serialization.serializeBigDecimal(bytes, issueAssetTransactionData.getFee());
-			bytes.write(issueAssetTransactionData.getSignature());
+
+			if (issueAssetTransactionData.getSignature() != null)
+				bytes.write(issueAssetTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {

src/transform/transaction/MessageTransactionTransformer.java

@@ -120,7 +120,9 @@ public class MessageTransactionTransformer extends TransactionTransformer {
 			bytes.write((byte) (messageTransactionData.getIsText() ? 1 : 0));
 
 			Serialization.serializeBigDecimal(bytes, messageTransactionData.getFee());
-			bytes.write(messageTransactionData.getSignature());
+
+			if (messageTransactionData.getSignature() != null)
+				bytes.write(messageTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {

src/transform/transaction/MultiPaymentTransactionTransformer.java

@@ -84,7 +84,9 @@ public class MultiPaymentTransactionTransformer extends TransactionTransformer {
 				PaymentTransformer.toBytes(paymentData);
 
 			Serialization.serializeBigDecimal(bytes, multiPaymentTransactionData.getFee());
-			bytes.write(multiPaymentTransactionData.getSignature());
+
+			if (multiPaymentTransactionData.getSignature() != null)
+				bytes.write(multiPaymentTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {

src/transform/transaction/TransferAssetTransactionTransformer.java

@@ -70,7 +70,9 @@ public class TransferAssetTransactionTransformer extends TransactionTransformer
 			Serialization.serializeBigDecimal(bytes, transferAssetTransactionData.getAmount(), AMOUNT_LENGTH);
 
 			Serialization.serializeBigDecimal(bytes, transferAssetTransactionData.getFee());
-			bytes.write(transferAssetTransactionData.getSignature());
+
+			if (transferAssetTransactionData.getSignature() != null)
+				bytes.write(transferAssetTransactionData.getSignature());
 
 			return bytes.toByteArray();
 		} catch (IOException | ClassCastException e) {