Data

java.lang.Object
- org.h2.store.Data

```
public class Data
extends java.lang.Object
```
This class represents a byte buffer that contains persistent data of a page.

Field Summary

Fields
Modifier and Type Field and Description

static int LENGTH_INT
The length of an integer value.

Fields
Modifier and Type	Field and Description
`static int`	`LENGTH_INT` The length of an integer value.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`checkCapacity(int plus)` Check if there is still enough capacity in the buffer.
`static void`	`copyString(java.io.Reader source, java.io.OutputStream target)` Copy a String from a reader to an output stream.
`static Data`	`create(DataHandler handler, byte[] buff)` Create a new buffer using the given data for the given handler.
`static Data`	`create(DataHandler handler, int capacity)` Create a new buffer for the given handler.
`void`	`fillAligned()` Fill up the buffer with empty space and an (initially empty) checksum until the size is a multiple of Constants.FILE_BLOCK_SIZE.
`byte[]`	`getBytes()` Get the byte array used for this page.
`DataHandler`	`getHandler()`
`static int`	`getStringLen(java.lang.String s)` Get the length of a String.
`int`	`getValueLen(Value v)` Calculate the number of bytes required to encode the given value.
`static int`	`getValueLen(Value v, DataHandler handler)` Calculate the number of bytes required to encode the given value.
`static int`	`getVarLongLen(long x)` The number of bytes required for a variable size long.
`int`	`length()` Get the current write position of this buffer, which is the current length.
`void`	`read(byte[] buff, int off, int len)` Copy a number of bytes to the given buffer from the current position.
`byte`	`readByte()` Read one single byte.
`int`	`readInt()` Read an integer at the current position.
`long`	`readLong()` Read a long value.
`short`	`readShortInt()` Read an short integer at the current position.
`java.lang.String`	`readString()` Read a String value.
`Value`	`readValue()` Read a value.
`int`	`readVarInt()` Read a variable size int.
`long`	`readVarLong()` Read a variable size long.
`void`	`reset()` Set the position to 0.
`void`	`setInt(int pos, int x)` Update an integer at the given position.
`void`	`setPos(int pos)` Set the current read / write position.
`void`	`truncate(int size)` Shrink the array to this size.
`void`	`write(byte[] buff, int off, int len)` Append a number of bytes to this buffer.
`void`	`writeByte(byte x)` Append one single byte.
`void`	`writeInt(int x)` Write an integer at the current position.
`void`	`writeLong(long x)` Append a long value.
`void`	`writeShortInt(int x)` Write a short integer at the current position.
`void`	`writeString(java.lang.String s)` Write a String.
`void`	`writeValue(Value v)` Append a value.
`void`	`writeVarInt(int x)` Write a variable size int.
`void`	`writeVarLong(long x)` Write a variable size long.

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

- Field Detail
  - LENGTH_INT
```
public static final int LENGTH_INT
```
    The length of an integer value.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - setInt
```
public void setInt(int pos,
                   int x)
```
    Update an integer at the given position. The current position is not change.
    
    Parameters:
    
    pos - the position
    
    x - the value
  - writeInt
```
public void writeInt(int x)
```
    Write an integer at the current position. The current position is incremented.
    
    Parameters:
    
    x - the value
  - readInt
```
public int readInt()
```
    Read an integer at the current position. The current position is incremented.
    
    Returns:
    
    the value
  - getStringLen
```
public static int getStringLen(java.lang.String s)
```
    Get the length of a String. This includes the bytes required to encode the length.
    
    Parameters:
    
    s - the string
    
    Returns:
    
    the number of bytes required
  - readString
```
public java.lang.String readString()
```
    Read a String value. The current position is incremented.
    
    Returns:
    
    the value
  - writeString
```
public void writeString(java.lang.String s)
```
    Write a String. The current position is incremented.
    
    Parameters:
    
    s - the value
  - create
```
public static Data create(DataHandler handler,
                          int capacity)
```
    Create a new buffer for the given handler. The handler will decide what type of buffer is created.
    
    Parameters:
    
    handler - the data handler
    
    capacity - the initial capacity of the buffer
    
    Returns:
    
    the buffer
  - create
```
public static Data create(DataHandler handler,
                          byte[] buff)
```
    Create a new buffer using the given data for the given handler. The handler will decide what type of buffer is created.
    
    Parameters:
    
    handler - the data handler
    
    buff - the data
    
    Returns:
    
    the buffer
  - length
```
public int length()
```
    Get the current write position of this buffer, which is the current length.
    
    Returns:
    
    the length
  - getBytes
```
public byte[] getBytes()
```
    Get the byte array used for this page.
    
    Returns:
    
    the byte array
  - reset
```
public void reset()
```
    Set the position to 0.
  - write
```
public void write(byte[] buff,
                  int off,
                  int len)
```
    Append a number of bytes to this buffer.
    
    Parameters:
    
    buff - the data
    
    off - the offset in the data
    
    len - the length in bytes
  - read
```
public void read(byte[] buff,
                 int off,
                 int len)
```
    Copy a number of bytes to the given buffer from the current position. The current position is incremented accordingly.
    
    Parameters:
    
    buff - the output buffer
    
    off - the offset in the output buffer
    
    len - the number of bytes to copy
  - writeByte
```
public void writeByte(byte x)
```
    Append one single byte.
    
    Parameters:
    
    x - the value
  - readByte
```
public byte readByte()
```
    Read one single byte.
    
    Returns:
    
    the value
  - readLong
```
public long readLong()
```
    Read a long value. This method reads two int values and combines them.
    
    Returns:
    
    the long value
  - writeLong
```
public void writeLong(long x)
```
    Append a long value. This method writes two int values.
    
    Parameters:
    
    x - the value
  - writeValue
```
public void writeValue(Value v)
```
    Append a value.
    
    Parameters:
    
    v - the value
  - readValue
```
public Value readValue()
```
    Read a value.
    
    Returns:
    
    the value
  - getValueLen
```
public int getValueLen(Value v)
```
    Calculate the number of bytes required to encode the given value.
    
    Parameters:
    
    v - the value
    
    Returns:
    
    the number of bytes required to store this value
  - getValueLen
```
public static int getValueLen(Value v,
                              DataHandler handler)
```
    Calculate the number of bytes required to encode the given value.
    
    Parameters:
    
    v - the value
    
    handler - the data handler for lobs
    
    Returns:
    
    the number of bytes required to store this value
  - setPos
```
public void setPos(int pos)
```
    Set the current read / write position.
    
    Parameters:
    
    pos - the new position
  - writeShortInt
```
public void writeShortInt(int x)
```
    Write a short integer at the current position. The current position is incremented.
    
    Parameters:
    
    x - the value
  - readShortInt
```
public short readShortInt()
```
    Read an short integer at the current position. The current position is incremented.
    
    Returns:
    
    the value
  - truncate
```
public void truncate(int size)
```
    Shrink the array to this size.
    
    Parameters:
    
    size - the new size
  - writeVarInt
```
public void writeVarInt(int x)
```
    Write a variable size int.
    
    Parameters:
    
    x - the value
  - readVarInt
```
public int readVarInt()
```
    Read a variable size int.
    
    Returns:
    
    the value
  - getVarLongLen
```
public static int getVarLongLen(long x)
```
    The number of bytes required for a variable size long.
    
    Parameters:
    
    x - the value
    
    Returns:
    
    the len
  - writeVarLong
```
public void writeVarLong(long x)
```
    Write a variable size long.
    
    Parameters:
    
    x - the value
  - readVarLong
```
public long readVarLong()
```
    Read a variable size long.
    
    Returns:
    
    the value
  - checkCapacity
```
public void checkCapacity(int plus)
```
    Check if there is still enough capacity in the buffer. This method extends the buffer if required.
    
    Parameters:
    
    plus - the number of additional bytes required
  - fillAligned
```
public void fillAligned()
```
    Fill up the buffer with empty space and an (initially empty) checksum until the size is a multiple of Constants.FILE_BLOCK_SIZE.
  - copyString
```
public static void copyString(java.io.Reader source,
                              java.io.OutputStream target)
                       throws java.io.IOException
```
    Copy a String from a reader to an output stream.
    
    Parameters:
    
    source - the reader
    
    target - the output stream
    
    Throws:
    
    java.io.IOException
  - getHandler
```
public DataHandler getHandler()
```

Class Data

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LENGTH_INT

Method Detail

setInt

writeInt

readInt

getStringLen

readString

writeString

create

create

length

getBytes

reset

write

read

writeByte

readByte

readLong

writeLong

writeValue

readValue

getValueLen

getValueLen

setPos

writeShortInt

readShortInt

truncate

writeVarInt

readVarInt

getVarLongLen

writeVarLong

readVarLong

checkCapacity

fillAligned

copyString

getHandler