org.forstdb.TransactionLogIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of forstjni Show documentation

ForSt fat jar with modifications specific for Apache Flink that contains .so files for linux32 and linux64 (glibc and musl-libc), jnilib files for Mac OSX, and a .dll for Windows x64.

The newest version!

// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
package org.forstdb;

/**
 * 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.forstdb.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.forstdb.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.forstdb.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.forstdb.WriteBatch}
     * instance
     *
     * @return {@link org.forstdb.WriteBatch} instance.
     */
    public WriteBatch writeBatch() {
      return writeBatch_;
    }

    private final long sequenceNumber_;
    private final WriteBatch writeBatch_;
  }

  @Override protected final native void disposeInternal(final long handle);
  private native boolean isValid(long handle);
  private native void next(long handle);
  private native void status(long handle)
      throws RocksDBException;
  private native BatchResult getBatch(long handle);
}