X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.db.common%2Fsrc%2Forg%2Fsimantics%2Fdb%2Fcommon%2FGraphSemaphore.java;fp=bundles%2Forg.simantics.db.common%2Fsrc%2Forg%2Fsimantics%2Fdb%2Fcommon%2FGraphSemaphore.java;h=2924f0275a394cb57e160a752c8323cb3c84f03d;hb=1a8971ec56f21b4532e22d787c3f5a15df0b5f2b;hp=0000000000000000000000000000000000000000;hpb=8744cc98e176b7f74f166fde5df76c84089a63b9;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.db.common/src/org/simantics/db/common/GraphSemaphore.java b/bundles/org.simantics.db.common/src/org/simantics/db/common/GraphSemaphore.java
new file mode 100644
index 000000000..2924f0275
--- /dev/null
+++ b/bundles/org.simantics.db.common/src/org/simantics/db/common/GraphSemaphore.java
@@ -0,0 +1,48 @@
+package org.simantics.db.common;
+
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+
+import org.simantics.db.AsyncReadGraph;
+import org.simantics.db.exception.DatabaseException;
+
+public class GraphSemaphore extends Semaphore {
+
+	private static final long serialVersionUID = 2114861433176831938L;
+	
+	private final AsyncReadGraph graph;
+	
+	public GraphSemaphore(AsyncReadGraph graph, int permits) {
+		super(permits);
+		this.graph = graph;
+	}
+
+	public void waitFor(int permits) throws DatabaseException, InterruptedException {
+		
+    	boolean success = false;
+    	success = tryAcquire(permits);
+    	if(success) return;
+    	
+    	while(!success) {
+    		
+    		if(graph.performPending()) {
+    			// Some task was done
+    			success = tryAcquire(permits);		
+    		} else {
+    			// Nothing to do - just wait
+            	try {
+        			success = tryAcquire(permits, 10, TimeUnit.SECONDS);
+        			if(!success) throw new DatabaseException("Timeout while waiting for async request to complete.");
+        		} catch (InterruptedException e) {
+        			throw new DatabaseException(e);
+        		}
+    		}
+    		    		
+    	}
+
+		
+	}
+	
+	
+
+}