Package net.i2p.data

Class SimpleDataStructure

java.lang.Object
net.i2p.data.SimpleDataStructure
All Implemented Interfaces:
DataStructure
Direct Known Subclasses:
EncryptedBuildRecord, Hash, Hash384, Hash512, NodeInfo, PrivateKey, PublicKey, SessionKey, SHA1Hash, Signature, SigningPrivateKey, SigningPublicKey
public abstract class SimpleDataStructure extends Object implements DataStructure
A SimpleDataStructure contains only a single fixed-length byte array. Implemented in 0.8.2 and retrofitted over several of the classes in this package. As of 0.8.3, SDS objects may be cached. An SDS may be instantiated with null data, and setData(null) is also OK. However, once non-null data is set, the data reference is immutable; subsequent attempts to set the data via setData(), readBytes(), fromByteArray(), or fromBase64() will throw a RuntimeException. As of 0.9.48, no longer extends DataStrucureImpl to save space
Since:
0.8.2
Author:
zzz

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected byte[]
    _data
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    SimpleDataStructure()
    A new instance with the data set to null.
    SimpleDataStructure(byte[] data)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    Hash
    calculateHash()
    Calculate the SHA256 value of this object (useful for a few scenarios)
    boolean
    equals(Object obj)
    Warning - this returns true for two different classes with the same size and same data, e.g.
    void
    fromBase64(String data)
    Sets the data.
    void
    fromByteArray(byte[] data)
    Does the same thing as setData() but null not allowed.
    byte[]
    getData()
    Get the data reference (not a copy)
    int
    hashCode()
    We assume the data has enough randomness in it, so use the first 4 bytes for speed.
    abstract int
    length()
    The legal length of the byte array in this data structure
    protected int
    read(InputStream in, byte[] target)
    Repeated reads until the buffer is full or IOException is thrown
    void
    readBytes(InputStream in)
    Sets the data.
    void
    setData(byte[] data)
    Sets the data.
    String
    toBase64()
    render the structure into modified base 64 notation
    byte[]
    toByteArray()
     
    String
    toString()
     
    void
    writeBytes(OutputStream out)
    Write out the data structure to the stream, using the format defined in the I2P data structure specification.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • _data

      protected byte[] _data

  • Constructor Details

    • SimpleDataStructure

      public SimpleDataStructure()
      A new instance with the data set to null. Call readBytes(), setData(), or fromByteArray() after this to set the data

    • SimpleDataStructure

      public SimpleDataStructure(byte[] data)
      Throws:
      IllegalArgumentException - if data is not the legal number of bytes (but null is ok)

  • Method Details

    • length

      public abstract int length()
      The legal length of the byte array in this data structure
      Since:
      0.8.2

    • getData

      public byte[] getData()
      Get the data reference (not a copy)
      Returns:
      the byte array, or null if unset

    • setData

      public void setData(byte[] data)
      Sets the data.
      Parameters:
      data - of correct length, or null
      Throws:
      IllegalArgumentException - if data is not the legal number of bytes (but null is ok)
      RuntimeException - if data already set.

    • readBytes

      public void readBytes(InputStream in) throws DataFormatException, IOException
      Sets the data.
      Specified by:
      readBytes in interface DataStructure
      Parameters:
      in - the stream to read
      Throws:
      RuntimeException - if data already set.
      DataFormatException - if the data is improperly formatted
      IOException - if there was a problem reading the stream

    • read

      protected int read(InputStream in, byte[] target) throws IOException
      Repeated reads until the buffer is full or IOException is thrown
      Returns:
      number of bytes read (should always equal target.length)
      Throws:
      IOException
      Since:
      0.9.48, copied from former superclass DataStructureImpl

    • writeBytes

      public void writeBytes(OutputStream out) throws DataFormatException, IOException
      Description copied from interface: DataStructure
      Write out the data structure to the stream, using the format defined in the I2P data structure specification.
      Specified by:
      writeBytes in interface DataStructure
      Parameters:
      out - stream to write to
      Throws:
      DataFormatException - if the data was incomplete or not yet ready to be written
      IOException - if there was a problem writing to the stream

    • toBase64

      public String toBase64()
      Description copied from interface: DataStructure
      render the structure into modified base 64 notation
      Specified by:
      toBase64 in interface DataStructure
      Returns:
      null on error

    • fromBase64

      public void fromBase64(String data) throws DataFormatException
      Sets the data.
      Specified by:
      fromBase64 in interface DataStructure
      Throws:
      DataFormatException - if decoded data is not the legal number of bytes or on decoding error
      RuntimeException - if data already set.

    • calculateHash

      public Hash calculateHash()
      Description copied from interface: DataStructure
      Calculate the SHA256 value of this object (useful for a few scenarios)
      Specified by:
      calculateHash in interface DataStructure
      Returns:
      the SHA256 hash of the byte array, or null if the data is null

    • toByteArray

      public byte[] toByteArray()
      Specified by:
      toByteArray in interface DataStructure
      Returns:
      same thing as getData()

    • fromByteArray

      public void fromByteArray(byte[] data) throws DataFormatException
      Does the same thing as setData() but null not allowed.
      Specified by:
      fromByteArray in interface DataStructure
      Parameters:
      data - non-null
      Throws:
      DataFormatException - if null or wrong length
      RuntimeException - if data already set.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • hashCode

      public int hashCode()
      We assume the data has enough randomness in it, so use the first 4 bytes for speed. If this is not the case, override in the extending class.
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Warning - this returns true for two different classes with the same size and same data, e.g. SessionKey and SessionTag, but you wouldn't put them in the same Set, would you?
      Overrides:
      equals in class Object