org.rocksdb.RocksIterator Maven / Gradle / Ivy
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
package org.rocksdb;
/**
* An iterator that yields a sequence of key/value pairs from a source.
* Multiple implementations are provided by this library.
* In particular, iterators are provided
* to access the contents of a Table or a DB.
*
* Multiple threads can invoke const methods on an RocksIterator without
* external synchronization, but if any of the threads may call a
* non-const method, all threads accessing the same RocksIterator must use
* external synchronization.
*
* @see org.rocksdb.RocksObject
*/
public class RocksIterator extends AbstractRocksIterator {
protected RocksIterator(RocksDB rocksDB, long nativeHandle) {
super(rocksDB, nativeHandle);
}
/**
* Return the key for the current entry. The underlying storage for
* the returned slice is valid only until the next modification of
* the iterator.
*
* REQUIRES: {@link #isValid()}
*
* @return key for the current entry.
*/
public byte[] key() {
assert(isOwningHandle());
return key0(nativeHandle_);
}
/**
* Return the value for the current entry. The underlying storage for
* the returned slice is valid only until the next modification of
* the iterator.
*
* REQUIRES: !AtEnd() && !AtStart()
* @return value for the current entry.
*/
public byte[] value() {
assert(isOwningHandle());
return value0(nativeHandle_);
}
@Override protected final native void disposeInternal(final long handle);
@Override final native boolean isValid0(long handle);
@Override final native void seekToFirst0(long handle);
@Override final native void seekToLast0(long handle);
@Override final native void next0(long handle);
@Override final native void prev0(long handle);
@Override final native void seek0(long handle, byte[] target, int targetLen);
@Override final native void seekForPrev0(long handle, byte[] target, int targetLen);
@Override final native void status0(long handle) throws RocksDBException;
private native byte[] key0(long handle);
private native byte[] value0(long handle);
}