Add an example for lots of entries.

src/test/java/net/openhft/chronicle/map/ChronicleMapTest.java

@@ -523,7 +523,6 @@ public class ChronicleMapTest {
         map.close();
     }
 
-    @Ignore("JIRA raised HCOLL-221")
     @Test
     public void testAcquireFromMultipleThreads() throws Exception {
         int entries = 1000 * 1000;
@@ -538,7 +537,7 @@ public class ChronicleMapTest {
         CharSequence key = getUserCharSequence(0);
         map.acquireUsing(key, new LongValue$$Native());
 
-        int iterations = 1000;
+        int iterations = 10000;
         int noOfThreads = 10;
         CyclicBarrier barrier = new CyclicBarrier(noOfThreads);
 

src/test/java/net/openhft/chronicle/map/example/LotsOfEntriesMain.java

@@ -0,0 +1,61 @@
+package net.openhft.chronicle.map.example;
+
+import net.openhft.chronicle.map.ChronicleMap;
+import net.openhft.chronicle.map.ChronicleMapBuilder;
+import net.openhft.lang.model.constraints.MaxSize;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Random;
+
+/**
+ * Created by peter on 19/12/14.
+ */
+public class LotsOfEntriesMain {
+    public static void main(String[] args) throws IOException {
+        workEntries(true);
+        workEntries(false);
+    }
+
+    private static void workEntries(boolean add) throws IOException {
+        long entries = 100_000_000;
+        File file = new File("/tmp/lotsOfEntries.dat");
+        ChronicleMap<CharSequence, MyFloats> map = ChronicleMapBuilder
+                .of(CharSequence.class, MyFloats.class)
+                .entries(entries)
+                .entrySize(80)
+                .createPersistedTo(file);
+        Random rand = new Random();
+        StringBuilder sb = new StringBuilder();
+        MyFloats mf = map.newValueInstance();
+        if (add)
+            for (int i = 0; i < 6; i++)
+                mf.setValueAt(i, i);
+        long start = System.nanoTime();
+        for (long i = 0; i < entries; i++) {
+            sb.setLength(0);
+            int length = (int) (24 / (rand.nextFloat() + 24.0 / 1000));
+            if (length > 2000)
+                throw new AssertionError();
+            sb.append(i);
+            while (sb.length() < length)
+                sb.append("-key");
+            if (add)
+                map.put(sb, mf);
+            else
+                map.getUsing(sb, mf);
+            if (i << -7 == 0 && i % 2000000 == 0)
+                System.out.println(i);
+        }
+        long time = System.nanoTime() - start;
+        System.out.printf("Map.size: %,d took an average of %,d ns to %s.%n",
+                map.size(), time / entries, add ? "add" : "get");
+        map.close();
+    }
+}
+
+interface MyFloats {
+    public void setValueAt(@MaxSize(6) int index, float f);
+
+    public float getValueAt(int index);
+}