DynamicByteArrayOutputStream (Apache Derby V10.13 Internals)

java.lang.Object
- java.io.OutputStream
- - org.apache.derby.iapi.services.io.DynamicByteArrayOutputStream

```
public class DynamicByteArrayOutputStream
extends java.io.OutputStream
```
A DynamicByteArrayOutputStream allows writing to a dynamically resizable array of bytes. In addition to dynamic resizing, this extension allows the user of this class to have more control over the position of the stream and can get a direct reference of the array.

Field Summary

Fields
Modifier and Type Field Description

private int beginPosition

private byte[] buf

private static int INITIAL_SIZE

private int position

private int used

Fields
Modifier and Type	Field	Description
`private int`	`beginPosition`
`private byte[]`	`buf`
`private static int`	`INITIAL_SIZE`
`private int`	`position`
`private int`	`used`

Constructor Summary

Constructors
Constructor	Description
`DynamicByteArrayOutputStream()`
`DynamicByteArrayOutputStream(byte[] data)`
`DynamicByteArrayOutputStream(int size)`
`DynamicByteArrayOutputStream(DynamicByteArrayOutputStream toBeCloned)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`
`void`	`discardLeft(int amountToShrinkBy)`	Shrink the buffer left by the amount given.
`private void`	`expandBuffer(int minExtension)`	Expand the buffer by at least the number of bytes requested in minExtension.
`int`	`getBeginPosition()`	Get the current position in the stream
`byte[]`	`getByteArray()`	Get a reference to the byte array stored in the byte array output stream.
`int`	`getPosition()`	Get the current position in the stream
`int`	`getUsed()`	Get the number of bytes that was used.
`void`	`reset()`	Reset the stream for reuse
`void`	`setBeginPosition(int newBeginPosition)`	Set the begin position of the stream pointer.
`void`	`setPosition(int newPosition)`	Set the position of the stream pointer.
`void`	`write(byte[] b, int off, int len)`
`void`	`write(int b)`
`(package private) void`	`writeCompleteStream(java.io.InputStream dataIn, int len)`

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

Methods inherited from class java.io.OutputStream
flush, write

- Field Detail
  - INITIAL_SIZE
```
private static int INITIAL_SIZE
```
  - buf
```
private byte[] buf
```
  - position
```
private int position
```
  - used
```
private int used
```
  - beginPosition
```
private int beginPosition
```
- Constructor Detail
  - DynamicByteArrayOutputStream
```
public DynamicByteArrayOutputStream()
```
  - DynamicByteArrayOutputStream
```
public DynamicByteArrayOutputStream(int size)
```
  - DynamicByteArrayOutputStream
```
public DynamicByteArrayOutputStream(byte[] data)
```
  - DynamicByteArrayOutputStream
```
public DynamicByteArrayOutputStream(DynamicByteArrayOutputStream toBeCloned)
```
- Method Detail
  - write
```
public void write(int b)
```
    Specified by:
    
    write in class java.io.OutputStream
  - write
```
public void write(byte[] b,
                  int off,
                  int len)
```
    Overrides:
    
    write in class java.io.OutputStream
  - writeCompleteStream
```
void writeCompleteStream(java.io.InputStream dataIn,
                         int len)
                  throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - close
```
public void close()
```
    Overrides:
    
    close in class java.io.OutputStream
  - reset
```
public void reset()
```
    Reset the stream for reuse
  - getByteArray
```
public byte[] getByteArray()
```
    Get a reference to the byte array stored in the byte array output stream. Note that the byte array may be longer that getPosition(). Bytes beyond and including the current poistion are invalid.
  - getUsed
```
public int getUsed()
```
    Get the number of bytes that was used.
  - getPosition
```
public int getPosition()
```
    Get the current position in the stream
  - getBeginPosition
```
public int getBeginPosition()
```
    Get the current position in the stream
  - setPosition
```
public void setPosition(int newPosition)
```
    Set the position of the stream pointer. It is up to the caller to make sure the stream has no gap of garbage in it or useful information is not left out at the end because the stream does not remember anything about the previous position.
  - setBeginPosition
```
public void setBeginPosition(int newBeginPosition)
```
    Set the begin position of the stream pointer. If the newBeginPosition is larger than the stream itself, then, the begin position is not set.
  - discardLeft
```
public void discardLeft(int amountToShrinkBy)
```
    Shrink the buffer left by the amount given. Ie. bytes from 0 to amountToShrinkBy are thrown away
  - expandBuffer
```
private void expandBuffer(int minExtension)
```
    Expand the buffer by at least the number of bytes requested in minExtension. To optimize performance and reduce memory copies and allocation, we have a staged buffer expansion.
    - buf.length < 128k - increase by 4k
    - buf.length < 1Mb - increase by 128k
    - otherwise increase by 1Mb.
    In all cases, if minExpansion is greater than the value about then the buffer will be increased by minExtension.

Class DynamicByteArrayOutputStream

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from class java.io.OutputStream

Field Detail

INITIAL_SIZE

buf

position

used

beginPosition

Constructor Detail

DynamicByteArrayOutputStream

DynamicByteArrayOutputStream

DynamicByteArrayOutputStream

DynamicByteArrayOutputStream

Method Detail

write

write

writeCompleteStream

close

reset

getByteArray

getUsed

getPosition

getBeginPosition

setPosition

setBeginPosition

discardLeft

expandBuffer