add DBIterator::SeekForPrev().

1. https://github.com/facebook/rocksdb/wiki/SeekForPrev
halibobor · Aug 22, 2022 · 7df88cf · 7df88cf
1 parent 84a391a
commit 7df88cf
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diff --git a/leveldb-api/src/main/java/org/iq80/leveldb/DBIterator.java b/leveldb-api/src/main/java/org/iq80/leveldb/DBIterator.java
@@ -33,6 +33,12 @@ public interface DBIterator
      */
     void seek(byte[] key);
 
+    /**
+     * seek to the last key that is less than or equal to the target key.
+     * @url https://github.com/facebook/rocksdb/wiki/SeekForPrev
+     */
+    void seekForPrev(byte[] key);
+
     /**
      * Repositions the iterator so is is at the beginning of the Database.
      */

diff --git a/leveldb/src/main/java/org/iq80/leveldb/impl/SeekingIteratorAdapter.java b/leveldb/src/main/java/org/iq80/leveldb/impl/SeekingIteratorAdapter.java
@@ -49,6 +49,12 @@ public void seek(byte[] targetKey)
         seekingIterator.seek(Slices.wrappedBuffer(targetKey));
     }
 
+    @Override
+    public void seekForPrev(byte[] targetKey)
+    {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public boolean hasNext()
     {