NetMask (Apache Tomcat 10.0.27 API Documentation)

java.lang.Object
- org.apache.catalina.util.NetMask

```
public final class NetMask
extends java.lang.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(java.lang.String input)
Constructor

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`matches(java.net.InetAddress addr)`	Test if a given address matches this netmask.
`boolean`	`matches(java.net.InetAddress addr, boolean checkedPort)`	Test if a given address matches this netmask.
`boolean`	`matches(java.net.InetAddress addr, int port)`	Test if a given address and port matches this netmask.
`java.lang.String`	`toString()`

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

- Constructor Detail
  - NetMask
```
public NetMask(java.lang.String input)
```
    Constructor
    
    Parameters:
    
    input - the CIDR netmask
    
    Throws:
    
    java.lang.IllegalArgumentException - if the netmask is not correct (invalid address specification, malformed CIDR prefix, etc)
- Method Detail
  - matches
```
public boolean matches(java.net.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(java.net.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(java.net.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 java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object