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

java.lang.Object
- net.i2p.data.DataStructureImpl
- - net.i2p.data.Lease

All Implemented Interfaces:
Serializable, DataStructure
Direct Known Subclasses:
Lease2, MetaLease
```
public class Lease
extends DataStructureImpl
```
Authorization grant proving a router/tunnel may receive messages for a destination.
Lease represents the fundamental routing authorization in I2P:
- Authorization: Proves specific router can receive messages
- Time-Bound: Valid only for specified time period
- Destination-Specific: Authorizes service for particular destination
- Tunnel Endpoint: Identifies specific tunnel on gateway router
Key Components:
- Gateway: Hash identifying the router hosting the tunnel
- Tunnel ID: TunnelId identifying specific tunnel on gateway
- End Time: long timestamp when lease expires
Authorization Model:
- Proof of Authority: Destination authorizes specific router
- Time Limitation: Authorization expires after set duration
- Tunnel Specificity: Authorizes particular tunnel, not all tunnels
- Renewable: Leases can be refreshed before expiration
Usage in LeaseSet:
- Multiple Leases: Destinations typically have several concurrent leases
- Load Balancing: Multiple leases distribute message load
- Redundancy: Backup tunnels if primary becomes unavailable
- Mobility: Leases updated as destination moves between routers
Network Operations:
- Message Routing: Routers use leases to forward messages
- Tunnel Selection: Senders choose from available leases
- Expiration Handling: Leases removed when they expire
- LeaseSet Publication: Leases published to network database
Security Considerations:
- Verification: Verify lease authenticity via LeaseSet signature
- Expiration: Ensure leases are still valid before use
- Gateway Trust: Verify gateway router is trusted
- Tunnel Security: Ensure tunnel endpoint is secure
Performance Aspects:
- Efficient Lookup: Hash-based gateway identification
- Quick Expiration: Timestamp comparison for validity checks
- Compact Storage: Minimal data structure for network transmission
- Fast Comparison: Optimized equals() and hashCode() methods
Related Structures:
- LeaseSet - Container for multiple leases
- Lease2 - Enhanced version with 4-byte timestamps
- MetaLease - References other LeaseSets instead of tunnels
- TunnelId - Tunnel identifier on gateway router
See Also:
Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected long`	`_end` Lease expiration time in milliseconds since epoch.
`protected Hash`	`_gateway` Gateway router hash.
`protected TunnelId`	`_tunnelId` Tunnel identifier on the gateway.

Constructor Summary
Constructors
Constructor and Description
Lease()
Required for deserialization.

Constructors
Constructor and Description
`Lease()` Required for deserialization.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object object)` Compares this Lease with another object for equality.
`Date`	`getEndDate()` Convenience wrapper, prefer getEndTime() for new code.
`long`	`getEndTime()` Gets the lease end time.
`Hash`	`getGateway()` Retrieve the router at which the destination can be contacted
`TunnelId`	`getTunnelId()` Tunnel on the gateway to communicate with
`int`	`hashCode()` Hash code based on end time, gateway, and tunnel ID.
`boolean`	`isExpired()` True if the lease has expired.
`boolean`	`isExpired(long fudgeFactor)` Fudge factor in milliseconds for clock skew.
`void`	`readBytes(InputStream in)` Reads the lease from an input stream.
`void`	`setEndDate(Date date)` Convenience wrapper, prefer the long overload for new code.
`void`	`setEndDate(long date)` Sets the lease end date.
`void`	`setGateway(Hash ident)` Configure the router at which the destination can be contacted
`void`	`setTunnelId(TunnelId id)` Configure the tunnel on the gateway to communicate with
`String`	`toString()` Returns a string representation of this Lease.
`void`	`writeBytes(OutputStream out)` Writes the lease to an output stream.

Methods inherited from class net.i2p.data.DataStructureImpl
calculateHash, fromBase64, fromByteArray, read, toBase64, toByteArray

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

- Field Detail
  - _end
```
protected long _end
```
    Lease expiration time in milliseconds since epoch.
  - _gateway
```
protected Hash _gateway
```
    Gateway router hash.
  - _tunnelId
```
protected TunnelId _tunnelId
```
    Tunnel identifier on the gateway.
- Constructor Detail
  - Lease
```
public Lease()
```
    Required for deserialization.
- Method Detail
  - equals
```
public boolean equals(Object object)
```
    Compares this Lease with another object for equality.
    Overrides:
    equals in class Object
  - getEndDate
```
public Date getEndDate()
```
    Convenience wrapper, prefer getEndTime() for new code.
    Returns:
    end date
  - getEndTime
```
public long getEndTime()
```
    Gets the lease end time.
    Returns:
    the end time
  - getGateway
```
public Hash getGateway()
```
    Retrieve the router at which the destination can be contacted
    Returns:
    identity of the router acting as a gateway
  - getTunnelId
```
public TunnelId getTunnelId()
```
    Tunnel on the gateway to communicate with
    Returns:
    tunnel ID
  - hashCode
```
public int hashCode()
```
    Hash code based on end time, gateway, and tunnel ID.
    Overrides:
    hashCode in class Object
  - isExpired
```
public boolean isExpired()
```
    True if the lease has expired.
    Returns:
    true if the lease has expired
  - isExpired
```
public boolean isExpired(long fudgeFactor)
```
    Fudge factor in milliseconds for clock skew.
    Parameters:
    fudgeFactor - fudge factor in milliseconds for clock skew
    Returns:
    true if the lease has expired
  - readBytes
```
public void readBytes(InputStream in)
               throws DataFormatException,
                      IOException
```
    Reads the lease from an input stream.
    Parameters:
    in - stream to read from
    Throws:
    DataFormatException - if the data is improperly formatted
    IOException - if there was a problem reading the stream
  - setEndDate
```
public void setEndDate(Date date)
```
    Convenience wrapper, prefer the long overload for new code.
    Parameters:
    date - end date
  - setEndDate
```
public void setEndDate(long date)
```
    Sets the lease end date.
  - setGateway
```
public void setGateway(Hash ident)
```
    Configure the router at which the destination can be contacted
    Parameters:
    ident - router acting as the gateway
  - setTunnelId
```
public void setTunnelId(TunnelId id)
```
    Configure the tunnel on the gateway to communicate with
    Parameters:
    id - tunnel ID
  - toString
```
public String toString()
```
    Returns a string representation of this Lease.
    Overrides:
    toString in class Object
  - writeBytes
```
public void writeBytes(OutputStream out)
                throws DataFormatException,
                       IOException
```
    Writes the lease to an output stream.
    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

Class Lease

Field Summary

Constructor Summary

Method Summary

Methods inherited from class net.i2p.data.DataStructureImpl

Methods inherited from class java.lang.Object

Field Detail

_end

_gateway

_tunnelId

Constructor Detail

Lease

Method Detail

equals

getEndDate

getEndTime

getGateway

getTunnelId

hashCode

isExpired

isExpired

readBytes

setEndDate

setEndDate

setGateway

setTunnelId

toString

writeBytes