From 9b85d8170f9b4b260270d9cb98d941a72e10926d Mon Sep 17 00:00:00 2001
From: Timm Fitschen <t.fitschen@indiscale.com>
Date: Fri, 5 Mar 2021 10:45:26 +0100
Subject: [PATCH] Activate fixed DatabaseAccessManager
---
.../caosdb/server/database/DatabaseAccessManager.java | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/src/main/java/org/caosdb/server/database/DatabaseAccessManager.java b/src/main/java/org/caosdb/server/database/DatabaseAccessManager.java
index 196a9fb2..f12c78e3 100644
--- a/src/main/java/org/caosdb/server/database/DatabaseAccessManager.java
+++ b/src/main/java/org/caosdb/server/database/DatabaseAccessManager.java
@@ -26,6 +26,7 @@
package org.caosdb.server.database;
import java.util.concurrent.Semaphore;
+import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantLock;
import org.caosdb.server.database.access.Access;
import org.caosdb.server.database.access.AccessControlAccess;
@@ -56,7 +57,7 @@ import org.caosdb.server.utils.Releasable;
class ReadAccessSemaphore extends Semaphore implements Releasable {
private static final long serialVersionUID = 4384921156838881337L;
- private int acquired = 0; // how many threads have read access
+ private AtomicInteger acquired = new AtomicInteger(0); // how many threads have read access
Semaphore writersBlock =
new Semaphore(1, true); // This semaphore is blocked as long as there are any
// unreleased read permits.
@@ -73,10 +74,9 @@ class ReadAccessSemaphore extends Semaphore implements Releasable {
@Override
public void acquire() throws InterruptedException {
super.acquire(); // Protect the next few lines
- if (this.acquired == 0) {
+ if (this.acquired.getAndIncrement() == 0) {
this.writersBlock.acquire();
}
- this.acquired++;
super.release();
}
@@ -87,9 +87,7 @@ class ReadAccessSemaphore extends Semaphore implements Releasable {
*/
@Override
public void release() {
- this.acquired--;
- if (this.acquired <= 0) { // Last permit: release
- this.acquired = 0;
+ if (this.acquired.decrementAndGet() == 0) { // Last permit: release
if (this.writersBlock.availablePermits() <= 0) {
this.writersBlock.release();
}
--
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