HCOLL-343 add an option not to erase old removed entries from ReplicatedChronicleMap

src/main/java/net/openhft/chronicle/hash/ChronicleHashBuilder.java

@@ -326,6 +326,18 @@ public interface ChronicleHashBuilder<K, H extends ChronicleHash<K, ?, ?, ?>,
      */
     B removedEntryCleanupTimeout(long removedEntryCleanupTimeout, TimeUnit unit);
 
+    /**
+     * Configures if replicated Chronicle Hashes, constructed by this builder, should
+     * completely erase entries, removed some time ago. See {@link #removedEntryCleanupTimeout(
+     * long, TimeUnit)} for more details on this mechanism.
+     *
+     * <p>Default value is {@code true} -- old removed entries are erased with 1 second timeout.
+     *
+     * @param cleanupRemovedEntries if stale removed entries should be purged from Chronicle Hash
+     * @return this builder back
+     */
+    B cleanupRemovedEntries(boolean cleanupRemovedEntries);
+
     /**
      * Configures a {@link BytesMarshallerFactory} to be used with {@link
      * BytesMarshallableSerializer}, which is a default {@link #objectSerializer ObjectSerializer},

src/main/java/net/openhft/chronicle/map/ChronicleMapBuilder.java

@@ -164,6 +164,7 @@ public final class ChronicleMapBuilder<K, V> implements
     // replication
     private TimeProvider timeProvider = TimeProvider.SYSTEM;
     long cleanupTimeout = 1;
+    private boolean cleanupRemovedEntries = true;
     TimeUnit cleanupTimeoutUnit = TimeUnit.SECONDS;
 
     private BytesMarshallerFactory bytesMarshallerFactory;
@@ -1075,6 +1076,12 @@ public final class ChronicleMapBuilder<K, V> implements
         return this;
     }
 
+    @Override
+    public ChronicleMapBuilder<K, V> cleanupRemovedEntries(boolean cleanupRemovedEntries) {
+        this.cleanupRemovedEntries = cleanupRemovedEntries;
+        return this;
+    }
+
     TimeProvider timeProvider() {
         return timeProvider;
     }
@@ -1571,7 +1578,8 @@ public final class ChronicleMapBuilder<K, V> implements
                 throw new AssertionError("Only one non-null replication should be passed");
 
             ReplicatedChronicleMap result = (ReplicatedChronicleMap) map;
-            establishCleanupThread(result);
+            if (cleanupRemovedEntries)
+                establishCleanupThread(result);
 
             List<Replicator> replicators = new ArrayList<>(2);
             if (singleHashReplication != null) {

src/main/java/net/openhft/chronicle/set/ChronicleSetBuilder.java

@@ -197,6 +197,12 @@ public final class ChronicleSetBuilder<K>
         return this;
     }
 
+    @Override
+    public ChronicleSetBuilder<K> cleanupRemovedEntries(boolean cleanupRemovedEntries) {
+        chronicleMapBuilder.cleanupRemovedEntries(cleanupRemovedEntries);
+        return this;
+    }
+
     @Override
     public ChronicleSetBuilder<K> bytesMarshallerFactory(
             BytesMarshallerFactory bytesMarshallerFactory) {