NodeInfo (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.i2p.data.SimpleDataStructure
- - org.klomp.snark.dht.NodeInfo

All Implemented Interfaces:
DataStructure
```
class NodeInfo
extends SimpleDataStructure
```
Comprehensive node information container for DHT operations.
This class encapsulates all essential information about a DHT node including its Node ID (NID), destination hash, port, and optionally the full I2P destination. It serves as the primary data structure stored in DHTNodes for routing table management and node discovery operations.
Data structure components:
- NID: 20-byte node identifier used for Kademlia distance calculations
- Hash: 32-byte destination hash for I2P routing
- Port: 2-byte network port for DHT communication
- Destination: Optional full I2P destination (may be added later)
The compact representation (54 bytes) is immutable and contains NID, hash, and port. This compact format is used for network transmission and efficient storage. The full destination may be added later when available, enabling direct communication with the node.
Design considerations:
- DHT exchanges often use only hashes initially, with destinations added later
- Compact format enables efficient network transmission and storage
- Immutable core data ensures consistency in routing operations
- Optional destination allows progressive information discovery

Field Summary
Fields
Modifier and Type Field and Description
static int LENGTH
Serialized length in bytes (NID + Hash + 2).
- Fields inherited from class net.i2p.data.SimpleDataStructure
  _data

Fields
Modifier and Type	Field and Description
`static int`	`LENGTH` Serialized length in bytes (NID + Hash + 2).

Constructor Summary

Constructors
Constructor and Description
`NodeInfo(byte[] compactInfo, int offset)` No Destination yet available.
`NodeInfo(Destination dest, int port)` With a fake NID used for pings
`NodeInfo(NID nID, Destination dest, int port)` Use this if we have the full destination.
`NodeInfo(NID nID, Hash hash, int port)` No Destination yet available.
`NodeInfo(String s)` Create from persistent storage string.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Hash`	`calculateHash()` calculateHash.
`boolean`	`equals(Object o)` equals.
`static NID`	`generateNID(Hash h, int p, RandomSource random)` Generate a secure NID that matches the Hash and port.
`Destination`	`getDestination()`
`Hash`	`getHash()`
`NID`	`getNID()`
`int`	`getPort()`
`int`	`hashCode()` We assume the data has enough randomness in it, so use the first 4 bytes for speed.
`long`	`lastSeen()`
`int`	`length()` The legal length of the byte array in this data structure.
`void`	`setDestination(Destination dest)` This can come in later but the hash must match.
`String`	`toPersistentString()` To persistent storage string.
`String`	`toString()` toString.

Methods inherited from class net.i2p.data.SimpleDataStructure
fromBase64, fromByteArray, getData, read, readBytes, setData, toBase64, toByteArray, writeBytes

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

- Field Detail
  - LENGTH
```
public static final int LENGTH
```
    Serialized length in bytes (NID + Hash + 2).
    See Also:
    Constant Field Values
- Constructor Detail
  - NodeInfo
```
public NodeInfo(byte[] compactInfo,
                int offset)
```
    No Destination yet available. Creates from compact node info.
    Parameters:
    compactInfo - 20 byte node ID, 32 byte destHash, 2 byte port
    offset - starting at this offset in compactInfo
    Throws:
    IllegalArgumentException - if port is invalid
    ArrayIndexOutOfBoundsException - if compactInfo is too short
  - NodeInfo
```
public NodeInfo(Destination dest,
                int port)
```
    With a fake NID used for pings
  - NodeInfo
```
public NodeInfo(NID nID,
                Destination dest,
                int port)
```
    Use this if we have the full destination.
    Parameters:
    nID - the node identifier
    dest - the full I2P destination
    port - the DHT query port
    Throws:
    IllegalArgumentException - if the NID does not match the destination hash
  - NodeInfo
```
public NodeInfo(NID nID,
                Hash hash,
                int port)
```
    No Destination yet available.
    Parameters:
    nID - the node identifier
    hash - the destination hash
    port - the DHT query port
    Throws:
    IllegalArgumentException - if the NID does not match the hash or port is invalid
  - NodeInfo
```
public NodeInfo(String s)
         throws DataFormatException
```
    Create from persistent storage string. Format: NID:Hash:Destination:port. First 3 in base 64; Destination may be empty string.
    Parameters:
    s - the persistent storage string
    Throws:
    DataFormatException - if the string format is invalid
    IllegalArgumentException - if the NID does not match the hash
- Method Detail
  - calculateHash
```
public Hash calculateHash()
```
    calculateHash.
    Specified by:
    calculateHash in interface DataStructure
    Overrides:
    calculateHash in class SimpleDataStructure
    Returns:
    SHA256 hash, or null if there were problems (data format or io errors)
  - equals
```
public boolean equals(Object o)
```
    equals.
    Overrides:
    equals in class SimpleDataStructure
    Parameters:
    o - the object to compare
    Returns:
    true if equal
  - generateNID
```
public static NID generateNID(Hash h,
                              int p,
                              RandomSource random)
```
    Generate a secure NID that matches the Hash and port. Rules: First 4 bytes must match Hash. Next 2 bytes must match Hash ^ port. Remaining bytes may be random.
    Parameters:
    h - the destination hash
    p - the port number
    random - the random
    Returns:
    the generated NID
  - getDestination
```
public Destination getDestination()
```
    Returns:
    may be null if we don't have it
  - getHash
```
public Hash getHash()
```
    Returns:
    the hash
  - getNID
```
public NID getNID()
```
    Returns:
    the n i d
  - getPort
```
public int getPort()
```
    Returns:
    the port
  - hashCode
```
public int hashCode()
```
    Description copied from class: SimpleDataStructure
    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 SimpleDataStructure
    Returns:
    whether h code is present
  - lastSeen
```
public long lastSeen()
```
  - length
```
public int length()
```
    Description copied from class: SimpleDataStructure
    The legal length of the byte array in this data structure.
    Specified by:
    length in class SimpleDataStructure
    Returns:
    the legal length of the byte array
  - setDestination
```
public void setDestination(Destination dest)
                    throws IllegalArgumentException
```
    This can come in later but the hash must match.
    Throws:
    IllegalArgumentException - if hash of dest doesn't match previous hash
  - toPersistentString
```
public String toPersistentString()
```
    To persistent storage string. Format: NID:Hash:Destination:port First 3 in base 64; Destination may be empty string
  - toString
```
public String toString()
```
    toString.
    Overrides:
    toString in class SimpleDataStructure

Class NodeInfo

Field Summary

Fields inherited from class net.i2p.data.SimpleDataStructure

Constructor Summary

Method Summary

Methods inherited from class net.i2p.data.SimpleDataStructure

Methods inherited from class java.lang.Object

Field Detail

LENGTH

Constructor Detail

NodeInfo

NodeInfo

NodeInfo

NodeInfo

NodeInfo

Method Detail

calculateHash

equals

generateNID

getDestination

getHash

getNID

getPort

hashCode

lastSeen

length

setDestination

toPersistentString

toString