added documentation for ILSMOperationTracker
git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_lsm_tree@1747 123451ca-8445-de46-9d55-352943316053
diff --git a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
index b845bd0..5df083d 100644
--- a/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
+++ b/hyracks-storage-am-lsm-common/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/common/api/ILSMOperationTracker.java
@@ -1,8 +1,30 @@
package edu.uci.ics.hyracks.storage.am.lsm.common.api;
+import edu.uci.ics.hyracks.storage.am.common.api.IIndexAccessor;
+/**
+ * This interface exposes methods for tracking when operations (e.g. insert, search)
+ * enter and exit an {@link ILSMIndex}.
+ *
+ * Note that 'operation' below refers to {@link IIndexAccessor} methods.
+ *
+ * @author zheilbron
+ */
public interface ILSMOperationTracker {
+
+ /**
+ * This method is guaranteed to be called whenever an operation first begins on the index,
+ * before any traversals of the index structures (more specifically, before any
+ * pages are pinned/latched).
+ *
+ * @param index the index for which the operation entered
+ */
public void threadEnter(ILSMIndex index);
+ /**
+ * This method is guaranteed to be called just before an operation is finished on the index.
+ *
+ * @param index the index for which the operation exited
+ */
public void threadExit(ILSMIndex index);
}