PLANNER-491 Give Partitioned Solver child Threads a good name

optaplanner-core/src/main/java/org/optaplanner/core/config/partitionedsearch/PartitionedSearchPhaseConfig.java

@@ -39,6 +39,7 @@
 import org.optaplanner.core.impl.partitionedsearch.partitioner.SolutionPartitioner;
 import org.optaplanner.core.impl.solver.recaller.BestSolutionRecaller;
 import org.optaplanner.core.impl.solver.termination.Termination;
+import org.optaplanner.core.impl.solver.thread.DefaultSolverThreadFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -141,7 +142,7 @@ private ThreadPoolExecutor buildThreadPoolExecutor() {
         if (threadFactoryClass != null) {
             threadFactory = ConfigUtils.newInstance(this, "threadFactoryClass", threadFactoryClass);
         } else {
-            threadFactory = Executors.defaultThreadFactory();
+            threadFactory = new DefaultSolverThreadFactory("PS-child-solver");
         }
         // Based on Executors.newCachedThreadPool(...)
         return new ThreadPoolExecutor(0, Integer.MAX_VALUE,

optaplanner-core/src/main/java/org/optaplanner/core/impl/solver/thread/DefaultSolverThreadFactory.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2016 Red Hat, Inc. and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.optaplanner.core.impl.solver.thread;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Similar to {@link Executors}'s DefaultThreadFactory, but allows settings a namePrefix.
+ */
+public class DefaultSolverThreadFactory implements ThreadFactory {
+
+    private static final AtomicInteger poolNumber = new AtomicInteger(1);
+
+    private final ThreadGroup group;
+    private final AtomicInteger threadNumber = new AtomicInteger(1);
+    private final String namePrefix;
+
+    public DefaultSolverThreadFactory() {
+        this("solver");
+    }
+
+    public DefaultSolverThreadFactory(String threadPrefix) {
+        this("planner-pool", threadPrefix);
+    }
+
+    public DefaultSolverThreadFactory(String poolPrefix, String threadPrefix) {
+        SecurityManager s = System.getSecurityManager();
+        group = (s != null) ? s.getThreadGroup() :
+                Thread.currentThread().getThreadGroup();
+        namePrefix = poolPrefix + "-" + poolNumber.getAndIncrement() + "-" + threadPrefix + "-";
+    }
+
+    @Override
+    public Thread newThread(Runnable r) {
+        Thread t = new Thread(group, r,
+                namePrefix + threadNumber.getAndIncrement(),
+                0);
+        if (t.isDaemon())
+            t.setDaemon(false);
+        if (t.getPriority() != Thread.NORM_PRIORITY)
+            t.setPriority(Thread.NORM_PRIORITY);
+        return t;
+    }
+
+}