org.rocksdb.RocksMutableObject Maven / Gradle / Ivy
// Copyright (c) 2016, 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;
/**
* RocksMutableObject is an implementation of {@link AbstractNativeReference}
* whose reference to the underlying native C++ object can change.
*
* The use of {@code RocksMutableObject} should be kept to a minimum, as it
* has synchronization overheads and introduces complexity. Instead it is
* recommended to use {@link RocksObject} where possible.
*/
public abstract class RocksMutableObject extends AbstractNativeReference {
/**
* An mutable reference to the value of the C++ pointer pointing to some
* underlying native RocksDB C++ object.
*/
private long nativeHandle_;
private boolean owningHandle_;
protected RocksMutableObject() {
}
protected RocksMutableObject(final long nativeHandle) {
this.nativeHandle_ = nativeHandle;
this.owningHandle_ = true;
}
/**
* Closes the existing handle, and changes the handle to the new handle
*
* @param newNativeHandle The C++ pointer to the new native object
* @param owningNativeHandle true if we own the new native object
*/
public synchronized void resetNativeHandle(final long newNativeHandle,
final boolean owningNativeHandle) {
close();
setNativeHandle(newNativeHandle, owningNativeHandle);
}
/**
* Sets the handle (C++ pointer) of the underlying C++ native object
*
* @param nativeHandle The C++ pointer to the native object
* @param owningNativeHandle true if we own the native object
*/
public synchronized void setNativeHandle(final long nativeHandle,
final boolean owningNativeHandle) {
this.nativeHandle_ = nativeHandle;
this.owningHandle_ = owningNativeHandle;
}
@Override
protected synchronized boolean isOwningHandle() {
return this.owningHandle_;
}
/**
* Gets the value of the C++ pointer pointing to the underlying
* native C++ object
*
* @return the pointer value for the native object
*/
protected synchronized long getNativeHandle() {
assert (this.nativeHandle_ != 0);
return this.nativeHandle_;
}
@Override
public synchronized final void close() {
if (isOwningHandle()) {
disposeInternal();
this.owningHandle_ = false;
this.nativeHandle_ = 0;
}
}
protected void disposeInternal() {
disposeInternal(nativeHandle_);
}
protected abstract void disposeInternal(final long handle);
}