enhance configuration api (#5774)

dubbo-common/src/main/java/org/apache/dubbo/common/config/ConfigurationUtils.java

@@ -37,11 +37,40 @@ import static org.apache.dubbo.common.constants.CommonConstants.SHUTDOWN_WAIT_SE
 public class ConfigurationUtils {
     private static final Logger logger = LoggerFactory.getLogger(ConfigurationUtils.class);
 
+    /**
+     * Used to get properties from the jvm
+     *
+     * @return
+     */
+    public static Configuration getSystemConfiguration() {
+        return ApplicationModel.getEnvironment().getSystemConfiguration();
+    }
+
+    /**
+     * Used to get properties from the os environment
+     *
+     * @return
+     */
+    public static Configuration getEnvConfiguration() {
+        return ApplicationModel.getEnvironment().getEnvironmentConfiguration();
+    }
+
+    /**
+     * Used to get an composite property value.
+     * <p>
+     * Also see {@link Environment#getConfiguration()}
+     *
+     * @return
+     */
+    public static Configuration getGlobalConfiguration() {
+        return ApplicationModel.getEnvironment().getConfiguration();
+    }
+
     // FIXME
     @SuppressWarnings("deprecation")
     public static int getServerShutdownTimeout() {
         int timeout = DEFAULT_SERVER_SHUTDOWN_TIMEOUT;
-        Configuration configuration = ApplicationModel.getEnvironment().getConfiguration();
+        Configuration configuration = getGlobalConfiguration();
         String value = StringUtils.trim(configuration.getString(SHUTDOWN_WAIT_KEY));
 
         if (value != null && value.length() > 0) {

dubbo-common/src/main/java/org/apache/dubbo/common/config/Environment.java

@@ -191,6 +191,26 @@ public class Environment extends LifecycleAdapter implements FrameworkExt {
         clearAppExternalConfigs();
     }
 
+    public PropertiesConfiguration getPropertiesConfiguration() {
+        return propertiesConfiguration;
+    }
+
+    public SystemConfiguration getSystemConfiguration() {
+        return systemConfiguration;
+    }
+
+    public EnvironmentConfiguration getEnvironmentConfiguration() {
+        return environmentConfiguration;
+    }
+
+    public InmemoryConfiguration getExternalConfiguration() {
+        return externalConfiguration;
+    }
+
+    public InmemoryConfiguration getAppExternalConfiguration() {
+        return appExternalConfiguration;
+    }
+
     // For test
     public void clearExternalConfigs() {
         this.externalConfiguration.clear();