io.camunda.zeebe.process.test.engine.InMemoryLogStorage Maven / Gradle / Ivy

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Test engine for running process tests. This a minimized version of the real Zeebe engine and should be used for testing purposes only.

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/*
 * Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH under
 * one or more contributor license agreements. See the NOTICE file distributed
 * with this work for additional information regarding copyright ownership.
 * Licensed under the Zeebe Community License 1.1. You may not use this file
 * except in compliance with the Zeebe Community License 1.1.
 */
package io.camunda.zeebe.process.test.engine;

import io.camunda.zeebe.logstreams.storage.LogStorage;
import io.camunda.zeebe.logstreams.storage.LogStorageReader;
import io.camunda.zeebe.util.buffer.BufferWriter;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentSkipListMap;
import org.agrona.DirectBuffer;
import org.agrona.concurrent.UnsafeBuffer;

class InMemoryLogStorage implements LogStorage {

  private final ConcurrentSkipListMap positionIndexMapping =
      new ConcurrentSkipListMap<>();
  private final List logEntries = new ArrayList<>();
  private final Set commitListeners = new HashSet<>();

  @Override
  public LogStorageReader newReader() {
    return new ListLogStorageReader();
  }

  @Override
  public void append(
      final long lowestPosition,
      final long highestPosition,
      final BufferWriter bufferWriter,
      final AppendListener listener) {
    final var buffer = ByteBuffer.allocate(bufferWriter.getLength());
    bufferWriter.write(new UnsafeBuffer(buffer), 0);
    append(lowestPosition, highestPosition, buffer, listener);
  }

  @Override
  public void append(
      final long lowestPosition,
      final long highestPosition,
      final ByteBuffer blockBuffer,
      final AppendListener listener) {
    logEntries.add(blockBuffer);
    final int index = logEntries.size();
    positionIndexMapping.put(lowestPosition, index);
    listener.onWrite(index, highestPosition);

    listener.onCommit(index, highestPosition);
    commitListeners.forEach(CommitListener::onCommit);
  }

  @Override
  public void addCommitListener(final CommitListener listener) {
    commitListeners.add(listener);
  }

  @Override
  public void removeCommitListener(final CommitListener listener) {
    commitListeners.remove(listener);
  }

  private class ListLogStorageReader implements LogStorageReader {

    private int currentIndex = 0;

    @Override
    public void seek(final long position) {
      currentIndex =
          Optional.ofNullable(positionIndexMapping.lowerEntry(position))
              .map(Entry::getValue)
              .map(index -> index - 1)
              .orElse(0);
    }

    @Override
    public void close() {}

    @Override
    public boolean hasNext() {
      return currentIndex >= 0 && currentIndex < logEntries.size();
    }

    @Override
    public DirectBuffer next() {
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      final int index = currentIndex;
      currentIndex++;
      return new UnsafeBuffer(logEntries.get(index));
    }
  }
}