Support for configuration based fixed network

src/main/java/org/qortal/network/Network.java

@@ -150,11 +150,25 @@ public class Network {
         }
 
         // Load all known peers from repository
+        synchronized (this.allKnownPeers) { List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+            if (fixedNetwork != null && !fixedNetwork.isEmpty()) {
+                Long addedWhen = NTP.getTime();
+                String addedBy = "fixedNetwork";
+                List<PeerAddress> peerAddresses = new ArrayList<>();
+                for (String address : fixedNetwork) {
+                    PeerAddress peerAddress = PeerAddress.fromString(address);
+                    peerAddresses.add(peerAddress);
+                }
+                List<PeerData> peers = peerAddresses.stream()
+                        .map(peerAddress -> new PeerData(peerAddress, addedWhen, addedBy))
+                        .collect(Collectors.toList());
+                this.allKnownPeers.addAll(peers);
+            } else {
                 try (Repository repository = RepositoryManager.getRepository()) {
-            synchronized (this.allKnownPeers) {
                     this.allKnownPeers.addAll(repository.getNetworkRepository().getAllPeers());
                 }
             }
+        }
 
         // Start up first networking thread
         networkEPC.start();
@@ -1115,6 +1129,10 @@ public class Network {
 
     private boolean mergePeers(Repository repository, String addedBy, long addedWhen, List<PeerAddress> peerAddresses)
             throws DataException {
+        List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+        if (fixedNetwork != null && !fixedNetwork.isEmpty()) {
+            return false;
+        }
         List<PeerData> newPeers;
         synchronized (this.allKnownPeers) {
             for (PeerData knownPeerData : this.allKnownPeers) {

src/main/java/org/qortal/settings/Settings.java

@@ -5,6 +5,7 @@ import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.Reader;
+import java.util.List;
 import java.util.Locale;
 
 import javax.xml.bind.JAXBContext;
@@ -147,6 +148,7 @@ public class Settings {
 	private String repositoryPath = "db";
 	/** Repository connection pool size. Needs to be a bit bigger than maxNetworkThreadPoolSize */
 	private int repositoryConnectionPoolSize = 100;
+	private List<String> fixedNetwork;
 
 	// Auto-update sources
 	private String[] autoUpdateRepos = new String[] {
@@ -507,4 +509,7 @@ public class Settings {
 		return this.onlineSignaturesTrimBatchSize;
 	}
 
+	public List<String> getFixedNetwork() {
+		return fixedNetwork;
+	}
 }