Github user ctubbsii commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/292#discussion_r132823444
--- Diff:
core/src/main/java/org/apache/accumulo/core/client/impl/Table.java ---
@@ -16,24 +16,59 @@
*/
package org.apache.accumulo.core.client.impl;
+import java.lang.ref.WeakReference;
+import java.util.WeakHashMap;
+
import org.apache.accumulo.core.client.Instance;
public class Table {
/**
* Object representing an internal table ID. This class was created to
help with type safety. For help obtaining the value of a table ID from
Zookeeper, see
* {@link Tables#getTableId(Instance, String)}
+ *
+ * Uses an internal WeakHashMap and private constructor for storing a
WeakReference of every Table.ID. Therefore, a Table.ID can't be instantiated
outside
+ * this class and is accessed by calling Table.ID.{@link #of(String)}.
*/
public static class ID extends AbstractId {
private static final long serialVersionUID = 7399913185860577809L;
+ static final WeakHashMap<String,WeakReference<Table.ID>> tableIds =
new WeakHashMap<>();
--- End diff --
It occurs to me that because of Java string interning, using a String as a
key may mean that entries are kept around longer than necessary. The
`WeakReference<Table.ID>` will still remove unused `Table.ID` objects and it
will dedupe when it does exist, but the map entry might stick around
unnecessarily because the String still has a strong reference because it's used
in more places than just the Table.ID. This could be avoided by always
constructing a new String and using that as the canonical parameter and the map
key... but not sure it's worth it.
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