Register shutdown hooks for caches, in the first step of cleaning up

resources on shutdown, which is important in Android as the JVM
isn't going away. More to do.

core/java/src/net/i2p/data/SDSCache.java

@@ -83,6 +83,18 @@ public class SDSCache<V extends SimpleDataStructure> {
             _log.debug("New SDSCache for " + rvClass + " data size: " + len +
                        " max: " + size + " max mem: " + (len * size));
         I2PAppContext.getGlobalContext().statManager().createRateStat(_statName, "Hit rate", "Router", new long[] { 10*60*1000 });
+        I2PAppContext.getGlobalContext().addShutdownTask(new Shutdown());
+    }
+
+    /**
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+            synchronized(_cache) {
+                _cache.clear();
+            }
+        }
     }
 
     /**

core/java/src/net/i2p/util/DecayingBloomFilter.java

@@ -107,8 +107,18 @@ public class DecayingBloomFilter {
         context.statManager().createRateStat("router.decayingBloomFilter." + name + ".log10(falsePos)",
              "log10 of the false positive rate (must have net.i2p.util.DecayingBloomFilter=DEBUG)",
              "Router", new long[] { Math.max(60*1000, durationMs) });
+        context.addShutdownTask(new Shutdown());
     }
     
+    /**
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+           clear();
+        }
+    }
+
     public long getCurrentDuplicateCount() { return _currentDuplicates; }
 
     public int getInsertedCount() { 

core/java/src/net/i2p/util/DecayingHashSet.java

@@ -93,8 +93,18 @@ public class DecayingHashSet extends DecayingBloomFilter {
              "Size", "Router", new long[] { Math.max(60*1000, durationMs) });
         context.statManager().createRateStat("router.decayingHashSet." + name + ".dups",
              "1000000 * Duplicates/Size", "Router", new long[] { Math.max(60*1000, durationMs) });
+        context.addShutdownTask(new Shutdown());
     }
     
+    /**
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+            clear();
+        }
+    }
+
     /** unsynchronized but only used for logging elsewhere */
     @Override
     public int getInsertedCount() { 

core/java/src/net/i2p/util/SimpleScheduler.java

@@ -2,6 +2,7 @@ package net.i2p.util;
 
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadFactory;
 
@@ -48,12 +49,25 @@ public class SimpleScheduler {
         _threads = (int) Math.max(MIN_THREADS, Math.min(MAX_THREADS, 1 + (maxMemory / (32*1024*1024))));
         _executor = new ScheduledThreadPoolExecutor(_threads, new CustomThreadFactory());
         _executor.prestartAllCoreThreads();
+        // don't bother saving ref to remove hook if somebody else calls stop
+        _context.addShutdownTask(new Shutdown());
     }
     
     /**
-     * Removes the SimpleScheduler.
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+            stop();
+        }
+    }
+
+    /**
+     * Stops the SimpleScheduler.
+     * Subsequent executions should not throw a RejectedExecutionException.
      */
     public void stop() {
+        _executor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
         _executor.shutdownNow();
     }
 

core/java/src/net/i2p/util/SimpleTimer.java

@@ -53,16 +53,32 @@ public class SimpleTimer {
             executor.setDaemon(true);
             executor.start();
         }
+        _context.addShutdownTask(new Shutdown());
     }
     
+    /**
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+            removeSimpleTimer();
+        }
+    }
+
     /**
      * Removes the SimpleTimer.
      */
     public void removeSimpleTimer() {
         synchronized(_events) {
             runn.setAnswer(false);
+            _events.clear();
+            _eventTimes.clear();
             _events.notifyAll();
         }
+        synchronized (_readyEvents) {
+            _readyEvents.clear();
+            _readyEvents.notifyAll();
+        }
     }
 
     /**

core/java/src/net/i2p/util/SimpleTimer2.java

@@ -3,6 +3,7 @@ package net.i2p.util;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ThreadFactory;
 
@@ -48,12 +49,25 @@ public class SimpleTimer2 {
         _threads = (int) Math.max(MIN_THREADS, Math.min(MAX_THREADS, 1 + (maxMemory / (32*1024*1024))));
         _executor = new CustomScheduledThreadPoolExecutor(_threads, new CustomThreadFactory());
         _executor.prestartAllCoreThreads();
+        // don't bother saving ref to remove hook if somebody else calls stop
+        _context.addShutdownTask(new Shutdown());
     }
     
     /**
-     * Removes the SimpleTimer.
+     * @since 0.8.8
+     */
+    private class Shutdown implements Runnable {
+        public void run() {
+            stop();
+        }
+    }
+
+    /**
+     * Stops the SimpleTimer.
+     * Subsequent executions should not throw a RejectedExecutionException.
      */
     public void stop() {
+        _executor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
         _executor.shutdownNow();
     }