[bugfix] wrapper kills eXist if it takes too long to start up or shut…

… down, resulting in fatal errors and potential data loss. Broker pool used to send signals to the wrapper to keep it waiting, but recently this failed due to broker pool being synchronized during startup. Solution: implement Observable on StatusReporter, which runs in a separate thread and is not subject to broker pool locks. Make it notify observers every 500ms.

src/org/exist/Database.java

@@ -55,9 +55,7 @@ public interface Database {
 
 	//TODO: javadocs
 
-	public String getId(); 
-
-	public void addObserver(Observer o);
+	public String getId();
 
 	/**
 	 * 

src/org/exist/storage/BrokerPool.java

@@ -92,7 +92,7 @@
  */
 //TODO : in the future, separate the design between the Map of DBInstances and their non static implementation
 @ConfigurationClass("pool")
-public class BrokerPool extends Observable implements Database {
+public class BrokerPool implements Database {
 
     private final static Logger LOG = Logger.getLogger(BrokerPool.class);
 
@@ -617,9 +617,6 @@ private BrokerPool(String instanceName, int minBrokers, int maxBrokers, Configur
 		Boolean aBoolean;
 		final NumberFormat nf = NumberFormat.getNumberInstance();
 
-        if (statusObserver != null)
-            {addObserver(statusObserver);}
-
         this.classLoader = Thread.currentThread().getContextClassLoader();
 
 		//TODO : ensure that the instance name is unique ?
@@ -813,7 +810,11 @@ protected void initialize() throws EXistException, DatabaseConfigurationExceptio
         synchronized (this) {
         	try {
         		statusReporter = new StatusReporter(SIGNAL_STARTUP);
-        		statusReporter.start();
+                if (statusObserver != null) {
+                    statusReporter.addObserver(statusObserver);
+                }
+                Thread statusThread = new Thread(statusReporter);
+        		statusThread.start();
 
         		// statusReporter may have to be terminated or the thread can/will hang.
         		try {
@@ -1886,7 +1887,11 @@ public void shutdown(boolean killed) {
             	// these may be used and set by other threads for the same or some other purpose
             	// (unlikely). Take no chances.
                 statusReporter = new StatusReporter(SIGNAL_SHUTDOWN);
-                statusReporter.start();
+                if (statusObserver != null) {
+                    statusReporter.addObserver(statusObserver);
+                }
+                Thread statusThread = new Thread(statusReporter);
+                statusThread.start();
 
                 // release transaction log to allow remaining brokers to complete
                 // their job
@@ -2084,7 +2089,7 @@ public void printSystemInfo() {
     	System.err.println(s);
     }
 
-    private class StatusReporter extends Thread {
+    private class StatusReporter extends Observable implements Runnable {
 
         private String status;
         private volatile boolean terminate = false;
@@ -2095,27 +2100,27 @@ public StatusReporter(String status) {
 
         public synchronized void setStatus(String status) {
             this.status = status;
-            BrokerPool.this.setChanged();
-            BrokerPool.this.notifyObservers(status);
+            this.setChanged();
+            this.notifyObservers(status);
         }
 
-        public void terminate() {
+        public synchronized void terminate() {
             this.terminate = true;
-            interrupt();
+            this.notifyAll();
         }
 
         public void run() {
             while (!terminate) {
                 synchronized (this) {
                     try {
-                        wait(300);
+                        wait(500);
                     } catch (final InterruptedException e) {
                         // nothing to do
                     }
                 }
+                this.setChanged();
+                this.notifyObservers(status);
             }
-            BrokerPool.this.setChanged();
-            BrokerPool.this.notifyObservers(status);
         }
     }