Add limit to number of proxy forging relationships per generator account.

For testing, current limit is 4 as set in blockchain.json

src/main/java/org/qora/block/BlockChain.java

@@ -107,6 +107,8 @@ public class BlockChain {
 	}
 	List<ForgingTier> forgingTiers;
 
+	private int maxProxyRelationships;
+
 	// Constructors, etc.
 
 	private BlockChain() {
@@ -259,6 +261,10 @@ public class BlockChain {
 		return this.forgingTiers;
 	}
 
+	public int getMaxProxyRelationships() {
+		return this.maxProxyRelationships;
+	}
+
 	// Convenience methods for specific blockchain feature triggers
 
 	public long getMessageReleaseHeight() {

src/main/java/org/qora/repository/AccountRepository.java

@@ -91,6 +91,10 @@ public interface AccountRepository {
 
 	public boolean isProxyPublicKey(byte[] publicKey) throws DataException;
 
+	public int countProxyAccounts(byte[] forgerPublicKey) throws DataException;
+
+	public List<ProxyForgerData> getProxyAccounts() throws DataException;
+
 	public List<ProxyForgerData> findProxyAccounts(List<String> recipients, List<String> forgers, List<String> involvedAddresses, Integer limit, Integer offset, Boolean reverse) throws DataException;
 
 	public void save(ProxyForgerData proxyForgerData) throws DataException;

src/main/java/org/qora/repository/hsqldb/HSQLDBAccountRepository.java

@@ -361,6 +361,42 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 	}
 
+	@Override
+	public int countProxyAccounts(byte[] forgerPublicKey) throws DataException {
+		String sql = "SELECT COUNT(*) FROM ProxyForgers WHERE forger = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, forgerPublicKey)) {
+			return resultSet.getInt(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to count proxy forging relationships in repository", e);
+		}
+	}
+
+	@Override
+	public List<ProxyForgerData> getProxyAccounts() throws DataException {
+		String sql = "SELECT forger, recipient, share, proxy_public_key FROM ProxyForgers";
+
+		List<ProxyForgerData> proxyAccounts = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return proxyAccounts;
+
+			do {
+				byte[] forgerPublicKey = resultSet.getBytes(1);
+				String recipient = resultSet.getString(2);
+				BigDecimal share = resultSet.getBigDecimal(3);
+				byte[] proxyPublicKey = resultSet.getBytes(4);
+
+				proxyAccounts.add(new ProxyForgerData(forgerPublicKey, recipient, proxyPublicKey, share));
+			} while (resultSet.next());
+
+			return proxyAccounts;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch proxy forge accounts from repository", e);
+		}
+	}
+
 	@Override
 	public List<ProxyForgerData> findProxyAccounts(List<String> recipients, List<String> forgers, List<String> involvedAddresses,
 			Integer limit, Integer offset, Boolean reverse) throws DataException {

src/main/java/org/qora/transaction/ProxyForgingTransaction.java

@@ -9,6 +9,7 @@ import org.qora.account.Account;
 import org.qora.account.Forging;
 import org.qora.account.PublicKeyAccount;
 import org.qora.asset.Asset;
+import org.qora.block.BlockChain;
 import org.qora.crypto.Crypto;
 import org.qora.data.account.ProxyForgerData;
 import org.qora.data.transaction.ProxyForgingTransactionData;
@@ -98,9 +99,15 @@ public class ProxyForgingTransaction extends Transaction {
 
 		// If proxy public key aleady exists in repository, then it must be for the same forger-recipient combo
 		ProxyForgerData proxyForgerData = this.repository.getAccountRepository().getProxyForgeData(this.proxyForgingTransactionData.getProxyPublicKey());
-		if (proxyForgerData != null)
+		if (proxyForgerData != null) {
 			if (!proxyForgerData.getRecipient().equals(recipient.getAddress()) || !Arrays.equals(proxyForgerData.getForgerPublicKey(), creator.getPublicKey()))
 				return ValidationResult.INVALID_PUBLIC_KEY;
+		} else {
+			// This is a new relationship - check that the generator hasn't reach maximum number of relationships
+			int relationshipCount = this.repository.getAccountRepository().countProxyAccounts(creator.getPublicKey());
+			if (relationshipCount >= BlockChain.getInstance().getMaxProxyRelationships())
+				return ValidationResult.MAXIMUM_PROXY_RELATIONSHIPS;
+		}
 
 		// Check fee is positive
 		if (proxyForgingTransactionData.getFee().compareTo(BigDecimal.ZERO) <= 0)

src/main/java/org/qora/transaction/Transaction.java

@@ -232,6 +232,7 @@ public abstract class Transaction {
 		AT_ALREADY_EXISTS(81),
 		GROUP_APPROVAL_NOT_REQUIRED(82),
 		GROUP_APPROVAL_DECIDED(83),
+		MAXIMUM_PROXY_RELATIONSHIPS(84),
 		NOT_YET_RELEASED(1000);
 
 		public final int value;

src/main/resources/blockchain.json

@@ -10,6 +10,7 @@
 	"requireGroupForApproval": false,
 	"defaultGroupId": 0,
 	"oneNamePerAccount": false,
+	"maxProxyRelationships": 4,
 	"genesisInfo": {
 		"version": 1,
 		"timestamp": "1400247274336",