Simplify and synchronized the way config is updated or checked

Author: Myron Scott

tc-server/src/main/java/com/tc/config/ServerConfigurationManager.java

@@ -17,7 +17,6 @@
  */
 package com.tc.config;
 
-
 import com.tc.classloader.ServiceLocator;
 import com.tc.productinfo.ProductInfo;
 import com.tc.properties.TCPropertiesImpl;
@@ -28,34 +27,39 @@
 import java.io.ByteArrayInputStream;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Properties;
 import org.terracotta.configuration.ConfigurationException;
 import com.tc.text.PrettyPrintable;
+import java.io.File;
+import java.net.InetSocketAddress;
 import java.util.List;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.stream.Collectors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class ServerConfigurationManager implements PrettyPrintable {
 
-  private final ConfigurationProvider configurationProvider;
+  private final Logger LOGGER = LoggerFactory.getLogger(ServerConfigurationManager.class);
+  private final CachingConfigurationProvider configurationProvider;
+  private ServerConfiguration thisServer;
   private final ServiceLocator serviceLocator;
   private final List<String> startUpArgs;
   private final ProductInfo productInfo;
 
-  private Configuration configuration;
-  private ServerConfiguration serverConfiguration;
-
   public ServerConfigurationManager(ConfigurationProvider configurationProvider,
-                                    ServiceLocator classLoader,
-                                    List<String> startUpArgs) {
+          ServiceLocator classLoader,
+          List<String> startUpArgs) {
     Objects.requireNonNull(configurationProvider);
     Objects.requireNonNull(classLoader);
     Objects.requireNonNull(startUpArgs);
 
-    this.configurationProvider = configurationProvider;
+    this.configurationProvider = new CachingConfigurationProvider(configurationProvider);
     this.serviceLocator = classLoader;
     this.startUpArgs = startUpArgs;
     this.productInfo = generateProductInfo(serviceLocator);
@@ -70,18 +74,24 @@ public ProductInfo getProductInfo() {
   }
 
   public void initialize() throws ConfigurationException {
-    this.configurationProvider.initialize(this.startUpArgs);
-    
-    this.configuration = configurationProvider.getConfiguration();
-    if (this.configuration == null) {
-      throw new ConfigurationException("unable to determine server configuration");
-    }
+    Lock lock = this.configurationProvider.lockAndInitialize(this.startUpArgs);
 
-    this.serverConfiguration = this.configuration.getServerConfiguration();
-    if (this.serverConfiguration == null) {
-      throw new ConfigurationException("unable to determine server configuration");
+    try {
+      Configuration configuration = configurationProvider.getConfiguration();
+      if (configuration == null) {
+        throw new ConfigurationException("unable to determine server configuration");
+      }
+
+      ServerConfiguration base = configuration.getServerConfiguration();
+      if (base == null) {
+        throw new ConfigurationException("unable to determine server configuration");
+      }
+      thisServer = new StableServerConfiguration(base);
+
+      processTcProperties(configuration.getTcProperties());
+    } finally {
+      lock.unlock();
     }
-    processTcProperties(configuration.getTcProperties());
   }
 
   public void close() {
@@ -93,69 +103,165 @@ public String[] getProcessArguments() {
   }
 
   public ServerConfiguration getServerConfiguration() {
-    return this.serverConfiguration;
+    return thisServer;
   }
 
   public GroupConfiguration getGroupConfiguration() {
-    List<ServerConfiguration> serverConfigurationMap = configuration.getServerConfigurations();
-    return new GroupConfiguration(serverConfigurationMap, this.serverConfiguration.getName());
+      List<ServerConfiguration> serverConfigurationMap = getConfiguration().getServerConfigurations().stream().map(StableServerConfiguration::new).collect(Collectors.toList());
+      return new GroupConfiguration(serverConfigurationMap, getServerConfiguration().getName());
   }
-  
+
   public InputStream rawConfigFile() {
-    String text = configuration.getRawConfiguration();
+    String text = getConfiguration().getRawConfiguration();
     return new ByteArrayInputStream(text.getBytes(StandardCharsets.UTF_8));
   }
 
   public String rawConfigString() {
-    return configuration.getRawConfiguration();
+    return getConfiguration().getRawConfiguration();
   }
 
   public String[] allCurrentlyKnownServers() {
     return getGroupConfiguration().getMembers();
   }
 
   public boolean isPartialConfiguration() {
-    return this.configuration.isPartialConfiguration();
+    return getConfiguration().isPartialConfiguration();
   }
 
   public ServiceLocator getServiceLocator() {
     return this.serviceLocator;
   }
 
   public Configuration getConfiguration() {
-    return configuration;
+    return configurationProvider.getConfiguration();
   }
 
   public ConfigurationProvider getConfigurationProvider() {
-    return configurationProvider;
-  }
-
-  private Map<String, ServerConfiguration> getServerConfigurationMap(Collection<ServerConfiguration> servers) {
-    Map<String, ServerConfiguration> serverConfigurationMap = new HashMap<>();
-    for (ServerConfiguration server : servers) {
-      if (server.getName() != null) {
-        serverConfigurationMap.put(server.getName(), server);
-      }
-    }
-    return serverConfigurationMap;
+    return configurationProvider.delegateProvider;
   }
 
   private static void processTcProperties(Properties tcProperties) {
     Map<String, String> propMap = new HashMap<>();
 
     if (tcProperties != null) {
-      tcProperties.forEach((k, v)->propMap.put(k.toString().trim(), v.toString().trim()));
+      tcProperties.forEach((k, v) -> propMap.put(k.toString().trim(), v.toString().trim()));
     }
 
     TCPropertiesImpl.getProperties().overwriteTcPropertiesFromConfig(propMap);
   }
 
   @Override
   public Map<String, ?> getStateMap() {
-    if (configuration instanceof PrettyPrintable) {
-      return ((PrettyPrintable)configuration).getStateMap();
+    Configuration config = getConfiguration();
+    if (config instanceof PrettyPrintable) {
+      return ((PrettyPrintable) config).getStateMap();
     } else {
       return Collections.emptyMap();
     }
   }
+
+  private static final class CachingConfigurationProvider implements ConfigurationProvider {
+
+    private final ConfigurationProvider delegateProvider;
+    private final Lock lock = new ReentrantLock();
+
+    public CachingConfigurationProvider(ConfigurationProvider delegateProvider) {
+      this.delegateProvider = delegateProvider;
+    }
+    
+    Lock lockAndInitialize(List<String> configurationParams) throws ConfigurationException {
+      lock.lock();
+      initialize(configurationParams);
+      return lock;
+    }
+
+    @Override
+    public void initialize(List<String> configurationParams) throws ConfigurationException {
+      delegateProvider.initialize(configurationParams);
+    }
+
+    @Override
+    public Configuration getConfiguration() {
+      lock.lock();
+      try {
+        return delegateProvider.getConfiguration();
+      } finally {
+        lock.unlock();
+      }
+    }
+
+    @Override
+    public String getConfigurationParamsDescription() {
+      return delegateProvider.getConfigurationParamsDescription();
+    }
+
+    @Override
+    public void close() {
+      delegateProvider.close();
+    }
+
+    @Override
+    public byte[] getSyncData() {
+      return delegateProvider.getSyncData();
+    }
+
+    @Override
+    public void sync(byte[] syncData) {
+      lock.lock();
+      try {
+        delegateProvider.sync(syncData);
+      } finally {
+        lock.unlock();
+      }
+    }
+  }
+  
+  private static class StableServerConfiguration implements ServerConfiguration {
+    
+    private final InetSocketAddress tsaPort;
+    private final InetSocketAddress groupPort;
+    private final String host;
+    private final String name;
+    private final int reconnectWindow;
+    private final File logDir;
+    
+    public StableServerConfiguration(ServerConfiguration base) {
+      tsaPort = base.getTsaPort();
+      groupPort = base.getGroupPort();
+      host = base.getHost();
+      name = base.getName();
+      reconnectWindow = base.getClientReconnectWindow();
+      logDir = base.getLogsLocation();
+    }
+
+    @Override
+    public InetSocketAddress getTsaPort() {
+      return tsaPort;
+    }
+
+    @Override
+    public InetSocketAddress getGroupPort() {
+      return groupPort;
+    }
+
+    @Override
+    public String getHost() {
+      return host;
+    }
+
+    @Override
+    public String getName() {
+      return name;
+    }
+
+    @Override
+    public int getClientReconnectWindow() {
+      return reconnectWindow;
+    }
+
+    @Override
+    public File getLogsLocation() {
+      return logDir;
+    }
+  }
 }