LogBlockIndex (Zeebe Logstreams 0.12.1 API)

java.lang.Object
- io.zeebe.logstreams.impl.log.index.LogBlockIndex

All Implemented Interfaces:

SnapshotSupport
```
public class LogBlockIndex
extends Object
implements SnapshotSupport
```
Block index, mapping an event's position to the physical address of the block in which it resides in storage.
Each Event has a position inside the stream. This position addresses it uniquely and is assigned when the entry is first published to the stream. The position never changes and is preserved through maintenance operations like compaction.
In order to read an event, the position must be translated into the "physical address" of the block in which it resides in storage. Then, the block can be scanned for the event position requested.

Field Summary

Fields
Modifier and Type Field and Description

protected int capacity

protected org.agrona.concurrent.AtomicBuffer indexBuffer

protected long lastVirtualPosition

Fields
Modifier and Type	Field and Description
`protected int`	`capacity`
`protected org.agrona.concurrent.AtomicBuffer`	`indexBuffer`
`protected long`	`lastVirtualPosition`

Constructor Summary

Constructors
Constructor and Description

LogBlockIndex(int capacity, java.util.function.Function<Integer,org.agrona.concurrent.AtomicBuffer> bufferAllocator)

Constructors
Constructor and Description
`LogBlockIndex(int capacity, java.util.function.Function<Integer,org.agrona.concurrent.AtomicBuffer> bufferAllocator)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`addBlock(long logPosition, long storageAddr)` Invoked by the log Appender thread after it has first written one or more entries to a block.
`int`	`capacity()`
`long`	`getAddress(int idx)`
`long`	`getLogPosition(int idx)`
`long`	`lookupBlockAddress(long position)` Returns the physical address of the block in which the log entry identified by the provided position resides.
`long`	`lookupBlockPosition(long position)` Returns the position of the first log entry of the the block in which the log entry identified by the provided position resides.
`protected int`	`lookupIndex(long position)` Returns the index of the block in which the log entry identified by the provided position resides.
`protected int`	`lookupOffset(long position)` Returns the offset of the block in which the log entry identified by the provided position resides.
`void`	`recoverFromSnapshot(InputStream inputStream)` read a snapshot from the provided input stream.
`void`	`reset()` Set the snapshot in the initial state.
`int`	`size()`
`long`	`writeSnapshot(OutputStream outputStream)` write a snapshot to the provided output stream

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - indexBuffer
```
protected final org.agrona.concurrent.AtomicBuffer indexBuffer
```
  - capacity
```
protected final int capacity
```
  - lastVirtualPosition
```
protected long lastVirtualPosition
```
- Constructor Detail
  - LogBlockIndex
```
public LogBlockIndex(int capacity,
                     java.util.function.Function<Integer,org.agrona.concurrent.AtomicBuffer> bufferAllocator)
```
- Method Detail
  - lookupBlockAddress
```
public long lookupBlockAddress(long position)
```
    Returns the physical address of the block in which the log entry identified by the provided position resides.
    
    Parameters:
    
    position - a virtual log position
    
    Returns:
    
    the physical address of the block containing the log entry identified by the provided virtual position
  - lookupBlockPosition
```
public long lookupBlockPosition(long position)
```
    Returns the position of the first log entry of the the block in which the log entry identified by the provided position resides.
    
    Parameters:
    
    position - a virtual log position
    
    Returns:
    
    the position of the block containing the log entry identified by the provided virtual position
  - lookupOffset
```
protected int lookupOffset(long position)
```
    Returns the offset of the block in which the log entry identified by the provided position resides.
    
    Parameters:
    
    position - a virtual log position
    
    Returns:
    
    the offset of the block containing the log entry identified by the provided virtual position
  - lookupIndex
```
protected int lookupIndex(long position)
```
    Returns the index of the block in which the log entry identified by the provided position resides.
    
    Parameters:
    
    position - a virtual log position
    
    Returns:
    
    the index of the block containing the log entry identified by the provided virtual position
  - addBlock
```
public int addBlock(long logPosition,
                    long storageAddr)
```
    Invoked by the log Appender thread after it has first written one or more entries to a block.
    
    Parameters:
    
    logPosition - the virtual position of the block (equal or smaller to the v position of the first entry in the block)
    
    storageAddr - the physical address of the block in the underlying storage
    
    Returns:
    
    the new size of the index.
  - size
```
public int size()
```
    Returns:
    
    the current size of the index
  - capacity
```
public int capacity()
```
    Returns:
    
    the capacity of the index
  - getLogPosition
```
public long getLogPosition(int idx)
```
  - getAddress
```
public long getAddress(int idx)
```
  - writeSnapshot
```
public long writeSnapshot(OutputStream outputStream)
                   throws Exception
```
    Description copied from interface: SnapshotSupport
    
    write a snapshot to the provided output stream
    
    Specified by:
    
    writeSnapshot in interface SnapshotSupport
    
    Parameters:
    
    outputStream - the stream to write to
    
    Returns:
    
    the size of the snapshot in bytes
    
    Throws:
    
    Exception
  - recoverFromSnapshot
```
public void recoverFromSnapshot(InputStream inputStream)
                         throws Exception
```
    Description copied from interface: SnapshotSupport
    
    read a snapshot from the provided input stream.
    
    Specified by:
    
    recoverFromSnapshot in interface SnapshotSupport
    
    Parameters:
    
    inputStream - the stream to read from
    
    Throws:
    
    Exception
  - reset
```
public void reset()
```
    Description copied from interface: SnapshotSupport
    
    Set the snapshot in the initial state.
    
    Specified by:
    
    reset in interface SnapshotSupport

Class LogBlockIndex

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

indexBuffer

capacity

lastVirtualPosition

Constructor Detail

LogBlockIndex

Method Detail

lookupBlockAddress

lookupBlockPosition

lookupOffset

lookupIndex

addBlock

size

capacity

getLogPosition

getAddress

writeSnapshot

recoverFromSnapshot

reset