Github user dlmarion commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/260#discussion_r119457446
--- Diff:
core/src/main/java/org/apache/accumulo/core/iterators/SortedKeyValueIterator.java
---
@@ -147,4 +147,35 @@
* if not supported.
*/
SortedKeyValueIterator<K,V> deepCopy(IteratorEnvironment env);
+
+ /**
+ * Called when the client (i.e. calling iterator or the tserver) will
support this iterators ability to yield. If called (and true is returned), then
when
+ * next or seek is called this iterator may yield before finding the
next top value and key. When this happens, the yield position (returned by
+ * getYieldPosition) will be used when this iterator is rebuilt to seek
to the position at which it yielded. This iterator can only yield if the user
of this
+ * iterator has called this method. Note that setYieldSupported will
never be called in row isolation mode.
+ *
+ * @return <tt>boolean</tt> True if this iterator supported yielding,
false otherwise.
+ */
+ default boolean setYieldSupported() {
+ return false;
+ }
+
+ /**
+ * If setYieldSupported has been called and true was returned, then this
method will be called after every seek and next call.
+ *
+ * @return <tt>boolean</tt> true if the previous next or seek call has
yielded without finding the next top key.
+ */
+ default boolean hasYielded() {
+ return false;
+ }
+
+ /**
+ * If hasYielded returned true, then this will return the key which will
be used as the start key (non-inclusive) of the range in the next seek call. No
other
+ * method will be called except for seek after calling this method.
+ *
+ * @return <tt>K</tt>
+ */
+ default K getYieldPosition() {
--- End diff --
Should this throw an IllegalStateException if hasYielded() returns false?
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