Package org.h2.store

Class 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 Description
      private byte[] data
      The data itself.
      private int pos
      The current write or read position.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private Data​(byte[] data)  

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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​(int capacity)
      Create a new buffer.
      private void expand​(int plus)  
      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.
      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.
      void reset()
      Set the position to 0.
      void setPos​(int pos)
      Set the current read / write position.
      void write​(byte[] buff, int off, int len)
      Append a number of bytes to this buffer.
      void writeInt​(int x)
      Write an integer at the current position.
      private void writeStringWithoutLength​(char[] chars, int len)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • data

        private byte[] data
        The data itself.

      • pos

        private int pos
        The current write or read position.

    • Constructor Detail

      • Data

        private Data​(byte[] data)

    • Method Detail

      • 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

      • writeStringWithoutLength

        private void writeStringWithoutLength​(char[] chars,
                                      int len)

      • create

        public static Data create​(int capacity)
        Create a new buffer.
        Parameters:
        capacity - the initial capacity of the buffer
        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

      • setPos

        public void setPos​(int pos)
        Set the current read / write position.
        Parameters:
        pos - the new position

      • readByte

        public byte readByte()
        Read one single byte.
        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

      • expand

        private void expand​(int plus)

      • 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 - on failure