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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
package org.rocksdb;
/**
* Base class for slices which will receive
* byte[] based access to the underlying data.
*
* byte[] backed slices typically perform better with
* small keys and values. When using larger keys and
* values consider using {@link org.rocksdb.DirectSlice}
*/
public class Slice extends AbstractSlice {
/**
* Called from JNI to construct a new Java Slice
* without an underlying C++ object set
* at creation time.
*
* Note: You should be aware that
* {@see org.rocksdb.RocksObject#disOwnNativeHandle()} is intentionally
* called from the default Slice constructor, and that it is marked as
* private. This is so that developers cannot construct their own default
* Slice objects (at present). As developers cannot construct their own
* Slice objects through this, they are not creating underlying C++ Slice
* objects, and so there is nothing to free (dispose) from Java.
*/
private Slice() {
super();
}
/**
* Constructs a slice where the data is taken from
* a String.
*
* @param str String value.
*/
public Slice(final String str) {
super(createNewSliceFromString(str));
}
/**
* Constructs a slice where the data is a copy of
* the byte array from a specific offset.
*
* @param data byte array.
* @param offset offset within the byte array.
*/
public Slice(final byte[] data, final int offset) {
super(createNewSlice0(data, offset));
}
/**
* Constructs a slice where the data is a copy of
* the byte array.
*
* @param data byte array.
*/
public Slice(final byte[] data) {
super(createNewSlice1(data));
}
/**
* Deletes underlying C++ slice pointer
* and any buffered data.
*
*
* Note that this function should be called only after all
* RocksDB instances referencing the slice are closed.
* Otherwise an undefined behavior will occur.
*/
@Override
protected void disposeInternal() {
final long nativeHandle = getNativeHandle();
disposeInternalBuf(nativeHandle);
super.disposeInternal(nativeHandle);
}
@Override protected final native byte[] data0(long handle);
private native static long createNewSlice0(final byte[] data,
final int length);
private native static long createNewSlice1(final byte[] data);
private native void disposeInternalBuf(final long handle);
}