diskUsage: replaced blocking sleep with semaphore

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@4957 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/tools/diskUsage.java

@@ -54,6 +54,7 @@ import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.Semaphore;
 
 import de.anomic.plasma.plasmaSwitchboard;
 import de.anomic.server.logging.serverLog;
@@ -470,16 +471,27 @@ nextLine:
     {
         private final InputStream stream;
         private final List<String> output = new ArrayList<String>();
+        private final Semaphore dataIsRead = new Semaphore(1);
+        /**
+         * FIXME just for debugging 
+         */
         private final String name;
-        private boolean done = false;
 
         public consoleInterface (final InputStream stream, String name)
         {
             this.stream = stream;
             this.name = name;
+            // block reading {@see getOutput()}
+            try {
+                dataIsRead.acquire();
+            } catch (InterruptedException e) {
+                // this should never happen because this is a constructor
+                e.printStackTrace();
+            }
         }
 
         public void run() {
+            // a second run adds data! a output.clear() maybe needed
             try {
                 final InputStreamReader input = new InputStreamReader(stream);
                 final BufferedReader buffer = new BufferedReader(input);
@@ -488,6 +500,7 @@ nextLine:
                 while (tries < 1000) {
                     tries++;
                     try {
+                        // may block!
                         Thread.sleep(1);
                     } catch (InterruptedException e) {
                         // just stop sleeping
@@ -499,22 +512,29 @@ nextLine:
                 while((line = buffer.readLine()) != null) {
                         output.add(line);
                 }
-                done  = true;
-            } catch(final IOException ix) { log.logWarning("logpoint 4 " +  ix.getMessage());}
+                dataIsRead.release();
+            } catch(final IOException ix) { log.logWarning("logpoint 6 " +  ix.getMessage());}
         }
         
+        /**
+         * waits until the stream is read and returns all data
+         * 
+         * @return lines of text in stream
+         */
         public List<String> getOutput(){
-            while(!isDone()) {
-                try {
-                    Thread.sleep(1);
-                } catch (InterruptedException e) {}
+            // wait that data is ready
+            try {
+                log.logInfo("logpoint 4 waiting for data of '"+ name +"'");
+                final long start = System.currentTimeMillis();
+                dataIsRead.acquire();
+                log.logInfo("logpoint 5 data ready for '"+ name +"' after "+ (System.currentTimeMillis() - start) +" ms");
+            } catch (InterruptedException e) {
+                // after interrupt just return what is available (maybe nothing)
             }
+            // is just for checking availability, so release it immediatly
+            dataIsRead.release();
             return output;
         }
-        
-        private boolean isDone() {
-            return done;
-        }
     }
 }