Changeset 14261 in josm for trunk/src/org/openstreetmap/josm/data/cache/HostLimitQueue.java

Timestamp:

2018-09-19T21:57:27+02:00 (6 years ago)

Author:

wiktorn

Message:

Use corePoolSize = maxPoolSize and unbounded queue

Remove hack with calling setCorePoolSize to spawn new threads when already
corePoolSize is running. For bigger sizes of the ThreadPool setCorePoolSize took
a long time and blocked EDT thread. Now we will have always `maximum concurren
downloads` threads running for TMS layers, but this is not a big issue, as the
thread pool is shared between imagery layers.

As long as number of threads will not reach the maximum concurrent downloads
the maximum concurrent downloads per host limit will not be enforced (first n
downloads).

See: #16734

File:

• trunk/src/org/openstreetmap/josm/data/cache/HostLimitQueue.java (modified) (4 diffs)

trunk/src/org/openstreetmap/josm/data/cache/HostLimitQueue.java

@@ -9 +9 @@
 import java.util.concurrent.LinkedBlockingDeque;
 import java.util.concurrent.Semaphore;
-import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
@@ -34 +33 @@
     private final int hostLimit;
 
-    private ThreadPoolExecutor executor;
-
-    private int corePoolSize;
-
-    private int maximumPoolSize;
-
     /**
      * Creates an unbounded queue
@@ -46 +39 @@
     public HostLimitQueue(int hostLimit) {
         super(); // create unbounded queue
+        this.hostLimit = hostLimit;
+    }
+
+    /**
+     * Creates bounded queue
+     * @param hostLimit how many parallel calls to host to allow
+     * @param queueLimit how deep the queue should be
+     */
+    public HostLimitQueue(int hostLimit, int queueLimit) {
+        super(queueLimit); // create bounded queue
         this.hostLimit = hostLimit;
     }
@@ -117 +120 @@
     }
 
-    /**
-     * Set the executor for which this queue works. It's needed to spawn new threads.
-     * See: http://stackoverflow.com/questions/9622599/java-threadpoolexecutor-strategy-direct-handoff-with-queue#
-     *
-     * @param executor executor for which this queue works
-     */
-    public void setExecutor(ThreadPoolExecutor executor) {
-        this.executor = executor;
-        this.maximumPoolSize = executor.getMaximumPoolSize();
-        this.corePoolSize = executor.getCorePoolSize();
-    }
-
-    @Override
-    public boolean offer(Runnable e) {
-        if (!super.offer(e)) {
-            return false;
-        }
-
-        if (executor != null) {
-            // See: http://stackoverflow.com/questions/9622599/java-threadpoolexecutor-strategy-direct-handoff-with-queue#
-            // force spawn of a thread if not reached maximum
-            int currentPoolSize = executor.getPoolSize();
-            if (currentPoolSize < maximumPoolSize
-                    && currentPoolSize >= corePoolSize) {
-                executor.setCorePoolSize(currentPoolSize + 1);
-                executor.setCorePoolSize(corePoolSize);
-            }
-        }
-        return true;
-    }
-
     private Semaphore getSemaphore(JCSCachedTileLoaderJob<?, ?> job) {
         String host;