Util: Add sort methods that catch IAE

apps/i2psnark/java/src/org/klomp/snark/web/I2PSnarkServlet.java

@@ -1490,11 +1490,8 @@ public class I2PSnarkServlet extends BasicServlet {
                 Sorters.setPattern(Translate.getLanguage(_manager.util().getContext()));
             else
                 Sorters.setPattern(null);
-            try {
-                Collections.sort(rv, Sorters.getComparator(sort, this));
-            } catch (IllegalArgumentException iae) {
             // Java 7 TimSort - may be unstable
-            }
+            DataHelper.sort(rv, Sorters.getComparator(sort, this));
         }
         return rv;
     }

apps/susimail/src/src/i2p/susi/util/Folder.java

@@ -34,6 +34,8 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
+import net.i2p.data.DataHelper;
+
 /**
  * Folder object manages a array Object[] to support
  * paging and sorting.
@@ -160,7 +162,7 @@ public class Folder<O extends Object> {
 	public synchronized void sort()
 	{
 		if (currentSorter != null && elements != null && elements.length > 1)
-			Arrays.sort( elements, currentSorter );
+			DataHelper.sort(elements, currentSorter);
 	}
 	
 	/**

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

@@ -29,9 +29,12 @@ import java.security.MessageDigest;
 import java.text.DecimalFormat;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Properties;
@@ -1997,4 +2000,54 @@ public class DataHelper {
             cache.release(ba);
         }
     }
+
+    /**
+      * Same as Collections.sort(), but guaranteed not to throw an IllegalArgumentException if the
+      * sort is unstable. As of Java 7, TimSort will throw an IAE if the underlying sort order
+      * changes during the sort.
+      *
+      * This catches the IAE, retries once, and then returns.
+      * If an IAE is thrown twice, this method will return, with the list possibly unsorted.
+      *
+      * @param list the list to be sorted.
+      * @param c the comparator to determine the order of the list. A null value indicates that the elements' natural ordering should be used.
+      * @since 0.9.34
+      */
+    public static <T> void sort(List<T> list, Comparator<? super T> c) {
+        try {
+            Collections.sort(list, c);
+        } catch (IllegalArgumentException iae1) {
+            try {
+                Thread.sleep(5);
+            } catch (InterruptedException ie) {}
+            try {
+                Collections.sort(list, c);
+            } catch (IllegalArgumentException iae2) {}
+        }
+    }
+
+    /**
+      * Same as Arrays.sort(), but guaranteed not to throw an IllegalArgumentException if the
+      * sort is unstable. As of Java 7, TimSort will throw an IAE if the underlying sort order
+      * changes during the sort.
+      *
+      * This catches the IAE, retries once, and then returns.
+      * If an IAE is thrown twice, this method will return, with the array possibly unsorted.
+      *
+      * @param a the array to be sorted.
+      * @param c the comparator to determine the order of the array. A null value indicates that the elements' natural ordering should be used.
+      * @since 0.9.34
+      */
+    public static <T> void sort(T[] a, Comparator<? super T> c) {
+        try {
+            Arrays.sort(a, c);
+        } catch (IllegalArgumentException iae1) {
+            try {
+                Thread.sleep(5);
+            } catch (InterruptedException ie) {}
+            try {
+                Arrays.sort(a, c);
+            } catch (IllegalArgumentException iae2) {}
+        }
+    }
 }

router/java/src/net/i2p/router/tunnel/pool/BuildExecutor.java

@@ -8,6 +8,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 
+import net.i2p.data.DataHelper;
 import net.i2p.data.Hash;
 import net.i2p.data.i2np.I2NPMessage;
 import net.i2p.data.router.RouterInfo;
@@ -382,12 +383,8 @@ class BuildExecutor implements Runnable {
                             // to the front of the line sometimes, to prevent being "locked up"
                             // for several minutes.
                             boolean preferEmpty = _context.random().nextInt(4) != 0;
-                            try {
-                                Collections.sort(wanted, new TunnelPoolComparator(preferEmpty));
-                            } catch (IllegalArgumentException iae) {
                             // Java 7 TimSort - see info in TunnelPoolComparator
-                                continue;
-                            }
+                            DataHelper.sort(wanted, new TunnelPoolComparator(preferEmpty));
                         }
 
                         // force the loops to be short, since 3 consecutive tunnel build requests can take