Package org.apache.catalina.util

Class NetMask

java.lang.Object

org.apache.catalina.util.NetMask

public final class NetMask
extends Object

A class representing a CIDR netmask.

The constructor takes a string as an argument which represents a netmask, as per the CIDR notation -- whether this netmask be IPv4 or IPv6. It then extracts the network address (before the /) and the CIDR prefix (after the /), and tells through the #matches() method whether a candidate InetAddress object fits in the recorded range.

As byte arrays as returned by InetAddress.getByName() are always in network byte order, finding a match is therefore as simple as testing whether the n first bits (where n is the CIDR) are the same in both byte arrays (the one of the network address and the one of the candidate address). We do that by first doing byte comparisons, then testing the last bits if any (that is, if the remainder of the integer division of the CIDR by 8 is not 0).

As a bonus, if no '/' is found in the input, it is assumed that an exact address match is required.

Constructor Summary

Constructors

Constructor	Description
NetMask(String input)	Constructor

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
int	hashCode()
boolean	matches(InetAddress addr)	Test if a given address matches this netmask.
boolean	matches(InetAddress addr, boolean checkedPort)	Test if a given address matches this netmask.
boolean	matches(InetAddress addr, int port)	Test if a given address and port matches this netmask.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

NetMask

public NetMask(String input)

Constructor

Parameters:

input - the CIDR netmask

Throws:

IllegalArgumentException - if the netmask is not correct (invalid address specification, malformed CIDR prefix, etc)

Method Details

matches

public boolean matches(InetAddress addr,
 int port)

Test if a given address and port matches this netmask.

Parameters:

addr - The InetAddress to test

port - The port to test

Returns:

true on match, false otherwise

matches

public boolean matches(InetAddress addr)

Test if a given address matches this netmask.

Parameters:

addr - The InetAddress to test

Returns:

true on match, false otherwise

matches

public boolean matches(InetAddress addr,
 boolean checkedPort)

Test if a given address matches this netmask.

Parameters:

addr - The InetAddress to test

checkedPort - Indicates, whether we already checked the port

Returns:

true on match, false otherwise

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object