import org.apache.cassandra.metrics.CommitLogMetrics; //导入依赖的package包/类
private CommitLog()
{
    DatabaseDescriptor.createAllDirectories();

    allocator = new CommitLogSegmentManager();

    executor = DatabaseDescriptor.getCommitLogSync() == Config.CommitLogSync.batch
             ? new BatchCommitLogService(this)
             : new PeriodicCommitLogService(this);

    MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
    try
    {
        mbs.registerMBean(this, new ObjectName("org.apache.cassandra.db:type=Commitlog"));
    }
    catch (Exception e)
    {
        throw new RuntimeException(e);
    }

    // register metrics
    metrics = new CommitLogMetrics(executor, allocator);
}
 

import org.apache.cassandra.metrics.CommitLogMetrics; //导入依赖的package包/类
private CommitLog()
{
    DatabaseDescriptor.createAllDirectories();

    allocator = new CommitLogAllocator();
    activateNextSegment();

    executor = DatabaseDescriptor.getCommitLogSync() == Config.CommitLogSync.batch
             ? new BatchCommitLogExecutorService()
             : new PeriodicCommitLogExecutorService(this);

    MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
    try
    {
        mbs.registerMBean(this, new ObjectName("org.apache.cassandra.db:type=Commitlog"));
    }
    catch (Exception e)
    {
        throw new RuntimeException(e);
    }

    // register metrics
    metrics = new CommitLogMetrics(executor, allocator);
}
 

import org.apache.cassandra.metrics.CommitLogMetrics; //导入依赖的package包/类
@VisibleForTesting
CommitLog(String location, CommitLogArchiver archiver)
{
    this.location = location;
    this.configuration = new Configuration(DatabaseDescriptor.getCommitLogCompression());
    DatabaseDescriptor.createAllDirectories();

    this.archiver = archiver;
    metrics = new CommitLogMetrics();

    executor = DatabaseDescriptor.getCommitLogSync() == Config.CommitLogSync.batch
            ? new BatchCommitLogService(this)
            : new PeriodicCommitLogService(this);

    allocator = new CommitLogSegmentManager(this);

    // register metrics
    metrics.attach(executor, allocator);
}
 

import org.apache.cassandra.metrics.CommitLogMetrics; //导入依赖的package包/类
public CommitLog(APIClient client) {
    super("org.apache.cassandra.db:type=Commitlog", client, new CommitLogMetrics());
}