FifoBuffer (Jenkins remoting layer 4.5 API)

java.lang.Object
- org.jenkinsci.remoting.nio.FifoBuffer

All Implemented Interfaces:

Closeable, AutoCloseable
```
public class FifoBuffer
extends Object
implements Closeable
```
FIFO buffer for a reader thread and a writer thread to collaborate. Unlike a ring buffer, which uses a fixed memory regardless of the number of bytes currently in the buffer, this implementation uses a single linked list to reduce the memory footprint when the reader closely follows the writer, regardless of the capacity limit set in the constructor. In trilead, the writer puts the data we receive from the network, and the user code acts as a reader. A user code normally drains the buffer more quickly than what the network delivers, so this implementation saves memory while simultaneously allowing us to advertise a bigger window size for a large latency network.

Since:

2.38

Author:

Kohsuke Kawaguchi

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class FifoBuffer.CloseCause
Explains the reason of the buffer close.

Nested Classes
Modifier and Type	Class and Description
`static class`	`FifoBuffer.CloseCause` Explains the reason of the buffer close.

Constructor Summary

Constructors
Constructor and Description
`FifoBuffer(int limit)`
`FifoBuffer(int pageSize, int limit)`
`FifoBuffer(Object lock, int pageSize, int limit)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Indicates that there will be no more write.
`FifoBuffer.CloseCause`	`getCloseCause()` Returns Exception with stacktrace of the command, which invoked the buffer close.
`InputStream`	`getInputStream()` Wraps the reader end of it to `InputStream`
`OutputStream`	`getOutputStream()` Wraps writer end of it to `OutputStream`.
`boolean`	`isClosed()` Returns true if the write end of the buffer is already closed, and that no more new data will arrive.
`int`	`peek(int offset, byte[] data)`
`int`	`peek(int offset, byte[] data, int start, int len)` Peek the specified number of bytes (`len`) at the specified offset in this buffer (`offset`) and places it into the specified position (`start`) of the array (`data`)
`int`	`read(byte[] buf)`
`int`	`read(byte[] buf, int start, int len)`
`int`	`readable()` Number of bytes available in this buffer that are readable.
`int`	`readNonBlocking(byte[] buf)`
`int`	`readNonBlocking(byte[] buf, int start, int len)`
`int`	`receive(ReadableByteChannel ch)` Read bytes from a channel and stores it into this buffer.
`int`	`send(WritableByteChannel ch)` Read from this buffer write as much as possible to the channel until the channel gets filled up.
`void`	`setLimit(int newLimit)` Set limit to the number of maximum bytes this buffer can hold.
`int`	`writable()` Number of bytes writable.
`void`	`write(byte[] buf)`
`void`	`write(byte[] buf, int start, int len)`
`int`	`writeNonBlock(ByteBuffer buf)` Non-blocking write.

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

- Constructor Detail
  - FifoBuffer
```
public FifoBuffer(int pageSize,
                  int limit)
```
  - FifoBuffer
```
public FifoBuffer(int limit)
```
  - FifoBuffer
```
public FifoBuffer(Object lock,
                  int pageSize,
                  int limit)
```
- Method Detail
  - setLimit
```
public void setLimit(int newLimit)
```
    Set limit to the number of maximum bytes this buffer can hold. Write methods will block if the size reaches the limit.
  - readable
```
public int readable()
```
    Number of bytes available in this buffer that are readable.
    
    Returns:
    
    -1 if the buffer is closed and there's no more data to read. May return non-negative value if the buffer close is requested, but not performed
  - writable
```
@Nonnegative
public int writable()
```
    Number of bytes writable.
    
    Returns:
    
    Number of bytes we can write to the buffer. If the buffer is closed, may return the value beyond the limit (JENKINS-37514)
  - isClosed
```
public boolean isClosed()
```
    Returns true if the write end of the buffer is already closed, and that no more new data will arrive. Note that there still might be a data left in the buffer to be read. The method may also return true when the close operation is actually requested.
  - getCloseCause
```
@CheckForNull
public FifoBuffer.CloseCause getCloseCause()
```
    Returns Exception with stacktrace of the command, which invoked the buffer close.
    
    Returns:
    
    Close cause or null
    
    Since:
    
    3.3
  - send
```
public int send(WritableByteChannel ch)
         throws IOException
```
    Read from this buffer write as much as possible to the channel until the channel gets filled up.
    
    Returns:
    
    number of bytes that were written. -1 if this buffer is EOF-ed and there will never be any more data to write.
    
    Throws:
    
    IOException
  - writeNonBlock
```
public int writeNonBlock(ByteBuffer buf)
```
    Non-blocking write.
    
    Returns:
    
    Number of writes written, possibly 0.
  - receive
```
public int receive(ReadableByteChannel ch)
            throws IOException
```
    Read bytes from a channel and stores it into this buffer.
    
    Returns:
    
    number of bytes read, or -1 if the given channel has reached EOF and no further read is possible.
    
    Throws:
    
    IOException - receive error
  - write
```
public void write(byte[] buf)
           throws InterruptedException,
                  IOException
```
    Throws:
    
    InterruptedException
    
    IOException
  - write
```
public void write(byte[] buf,
                  int start,
                  int len)
           throws InterruptedException,
                  IOException
```
    Throws:
    
    InterruptedException
    
    IOException
  - close
```
public void close()
```
    Indicates that there will be no more write. Once the remaining bytes are drained by the reader, the read method will start returning EOF signals.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
  - peek
```
public int peek(int offset,
                byte[] data,
                int start,
                int len)
```
    Peek the specified number of bytes (len) at the specified offset in this buffer (offset) and places it into the specified position (start) of the array (data)
    
    Returns:
    
    number of bytes actually peeked. Can be 0 if the offset goes beyond the current readable size in this buffer. Never negative.
  - peek
```
public int peek(int offset,
                byte[] data)
```
  - read
```
public int read(byte[] buf)
         throws InterruptedException
```
    Throws:
    
    InterruptedException
  - read
```
public int read(byte[] buf,
                int start,
                int len)
         throws InterruptedException
```
    Throws:
    
    InterruptedException
    
    See Also:
    
    InputStream.read(byte[],int,int)
  - readNonBlocking
```
public int readNonBlocking(byte[] buf)
```
  - readNonBlocking
```
public int readNonBlocking(byte[] buf,
                           int start,
                           int len)
```
    See Also:
    
    InputStream.read(byte[],int,int)
  - getOutputStream
```
public OutputStream getOutputStream()
```
    Wraps writer end of it to OutputStream.
  - getInputStream
```
public InputStream getInputStream()
```
    Wraps the reader end of it to InputStream

Class FifoBuffer

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FifoBuffer

FifoBuffer

FifoBuffer

Method Detail

setLimit

readable

writable

isClosed

getCloseCause

send

writeNonBlock

receive

write

write

close

peek

peek

read

read

readNonBlocking

readNonBlocking

getOutputStream

getInputStream