org.rocksdb.TransactionLogIterator Maven / Gradle / Ivy
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// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
package org.rocksdb;
/**
* A TransactionLogIterator is used to iterate over the transactions in a db.
* One run of the iterator is continuous, i.e. the iterator will stop at the
* beginning of any gap in sequences.
*/
public class TransactionLogIterator extends RocksObject {
/**
* An iterator is either positioned at a WriteBatch
* or not valid. This method returns true if the iterator
* is valid. Can read data from a valid iterator.
*
* @return true if iterator position is valid.
*/
public boolean isValid() {
return isValid(nativeHandle_);
}
/**
* Moves the iterator to the next WriteBatch.
* REQUIRES: Valid() to be true.
*/
public void next() {
next(nativeHandle_);
}
/**
* Throws RocksDBException if something went wrong.
*
* @throws org.rocksdb.RocksDBException if something went
* wrong in the underlying C++ code.
*/
public void status() throws RocksDBException {
status(nativeHandle_);
}
/**
* If iterator position is valid, return the current
* write_batch and the sequence number of the earliest
* transaction contained in the batch.
*
* ONLY use if Valid() is true and status() is OK.
*
* @return {@link org.rocksdb.TransactionLogIterator.BatchResult}
* instance.
*/
public BatchResult getBatch() {
assert(isValid());
return getBatch(nativeHandle_);
}
/**
* TransactionLogIterator constructor.
*
* @param nativeHandle address to native address.
*/
TransactionLogIterator(final long nativeHandle) {
super(nativeHandle);
}
/**
* BatchResult represents a data structure returned
* by a TransactionLogIterator containing a sequence
* number and a {@link WriteBatch} instance.
*/
public static final class BatchResult {
/**
* Constructor of BatchResult class.
*
* @param sequenceNumber related to this BatchResult instance.
* @param nativeHandle to {@link org.rocksdb.WriteBatch}
* native instance.
*/
public BatchResult(final long sequenceNumber,
final long nativeHandle) {
sequenceNumber_ = sequenceNumber;
writeBatch_ = new WriteBatch(nativeHandle, true);
}
/**
* Return sequence number related to this BatchResult.
*
* @return Sequence number.
*/
public long sequenceNumber() {
return sequenceNumber_;
}
/**
* Return contained {@link org.rocksdb.WriteBatch}
* instance
*
* @return {@link org.rocksdb.WriteBatch} instance.
*/
public WriteBatch writeBatch() {
return writeBatch_;
}
private final long sequenceNumber_;
private final WriteBatch writeBatch_;
}
@Override
protected final void disposeInternal(final long handle) {
disposeInternalJni(handle);
}
private static native void disposeInternalJni(final long handle);
private static native boolean isValid(long handle);
private static native void next(long handle);
private static native void status(long handle) throws RocksDBException;
private static native BatchResult getBatch(long handle);
}