com.hp.util.ip

Class SubnetMask

java.lang.Object

com.hp.util.cache.CacheableDataType

com.hp.util.ip.SubnetMask

All Implemented Interfaces:

Serializable, Comparable<SubnetMask>

public final class SubnetMask
extends CacheableDataType
implements Comparable<SubnetMask>

Represents a subnet mask (either IPv4 or IPv6).

All constructors for this class are private. Creating instances of SubnetMask is done via the static methods on the class.

Instances of this class are immutable, making them inherently thread-safe.

This class overrides equals(java.lang.Object) and hashCode() so that instances play nicely with the Collection classes.

This class implements the Comparable interface to ensure that a sorted list of subnet masks is presented in an intuitive order.

Author:

Simon Hunt

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static SubnetMask	MASK_255_0_0_0
static SubnetMask	MASK_255_255_0_0
static SubnetMask	MASK_255_255_248_0
static SubnetMask	MASK_255_255_255_0

Method Summary

Methods

Modifier and Type	Method and Description
int	compareTo(SubnetMask o)
boolean	equals(Object o)
static SubnetMask	fromCidr(String cidr) Returns a SubnetMask object that represents the value of the subnet mask implied by the given CIDR notation.
IpAddress.Family	getFamily() Returns the IP address family of this subnet mask.
int	getOneBitCount() Returns the number of 1 bits in the mask.
int	hashCode()
IpAddress	hostPortion(IpAddress address) Applies this mask (via logical AND of NOT(mask) ) to calculate and return the host portion of the specified address.
IpAddress	networkPortion(IpAddress address) Applies this mask (via logical AND) to calculate and return the network portion of the specified address.
byte[]	toByteArray() Returns a newly allocated byte array containing bytes that represent the subnet mask.
String	toDebugString() Returns a string representation of this subnet mask showing the internal state.
IpAddress	toIpAddress() Returns the IP address equivalent to this subnet mask.
String	toString()
static SubnetMask	valueOf(byte[] maskBytes) Returns a SubnetMask object that represents the subnet mask defined by the specified byte array.
static SubnetMask	valueOf(IpAddress mask) Returns a SubnetMask object that represents the subnet mask with the value of the given IP address.
static SubnetMask	valueOf(String mask) Returns a SubnetMask object that represents the value of the subnet mask defined by the specified string.

Methods inherited from class com.hp.util.cache.CacheableDataType

getRefQ, keyFromBytes

Methods inherited from class java.lang.Object

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

Field Detail

MASK_255_0_0_0

public static final SubnetMask MASK_255_0_0_0

MASK_255_255_0_0

public static final SubnetMask MASK_255_255_0_0

MASK_255_255_248_0

public static final SubnetMask MASK_255_255_248_0

MASK_255_255_255_0

public static final SubnetMask MASK_255_255_255_0

Method Detail

toString

public String toString()

Overrides:

toString in class Object

toDebugString

public String toDebugString()

Returns a string representation of this subnet mask showing the internal state.

Returns:

a debug string representation

toByteArray

public byte[] toByteArray()

Returns a newly allocated byte array containing bytes that represent the subnet mask. This will be an array of length 4 for an IPv4 subnet mask, and an array of length 16 for an IPv6 subnet mask. Note that the address bytes are in network byte order; that is, the highest order byte of the address is at index 0.

Returns:

a byte array representing the subnet mask

toIpAddress

public IpAddress toIpAddress()

Returns the IP address equivalent to this subnet mask.

Returns:

the equivalent IP address

getFamily

public IpAddress.Family getFamily()

Returns the IP address family of this subnet mask.

Returns:

the IP address family

getOneBitCount

public int getOneBitCount()

Returns the number of 1 bits in the mask.

Returns:

the number of 1 bits

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(SubnetMask o)

Specified by:

compareTo in interface Comparable<SubnetMask>

networkPortion

public IpAddress networkPortion(IpAddress address)

Applies this mask (via logical AND) to calculate and return the network portion of the specified address. For example:

 SubnetMask.MASK_255_255_248_0
           .networkPortion(IpAddress.valueOf("15.37.129.123"))
 

will return the "IP address" 15.37.128.0

Parameters:

address - the address to process

Returns:

an IP address representing the "network portion" of the given address

Throws:

NullPointerException - if address is null

IllegalArgumentException - if there is a mismatch of IPv4/IPv6

hostPortion

public IpAddress hostPortion(IpAddress address)

Applies this mask (via logical AND of NOT(mask) ) to calculate and return the host portion of the specified address. For example:

 SubnetMask.MASK_255_255_248_0
           .hostPortion(IpAddress.valueOf("15.37.129.123"))
 

will return the "IP address" 0.0.1.123

Parameters:

address - the address to process

Returns:

an IP address representing the "host portion" of the given address

Throws:

NullPointerException - if address is null

IllegalArgumentException - if there is a mismatch of IPv4/IPv6

valueOf

public static SubnetMask valueOf(IpAddress mask)

Returns a SubnetMask object that represents the subnet mask with the value of the given IP address.

Parameters:

mask - the subnet mask value expressed as an IP address

Returns:

the subnet mask instance

Throws:

NullPointerException - if mask is null

IllegalArgumentException - if mask is not a valid value for a subnet mask

valueOf

public static SubnetMask valueOf(byte[] maskBytes)

Returns a SubnetMask object that represents the subnet mask defined by the specified byte array. Note that the mask bytes are presumed to be in network byte order; that is, the highest order byte of the mask is at index 0.

If the bytes array is of length 4, it is interpretted as an IPv4 subnet mask. If the bytes array is of length 16, it is interpretted as an IPv6 subnet mask. Other array lengths will throw an exception.

Parameters:

maskBytes - the subnet mask bytes

Returns:

the subnet mask instance

Throws:

NullPointerException - if maskBytes is null

IllegalArgumentException - if maskBytes do not define a valid subnet mask

valueOf

public static SubnetMask valueOf(String mask)

Returns a SubnetMask object that represents the value of the subnet mask defined by the specified string. Both uppercase and lowercase hex digits are allowed (for IPv6 masks).

Acceptable formats are:

• IPv4: dotted decimal format ("n.n.n.n") -- where 'n' is from 0 to 255
• IPv6: eight groups of hexadecimal digits, separated by colon ("x:x:x:x:x:x:x:x") -- where 'x' is from 0000 to FFFF. Leading zeros may be dropped.
• IPv6: shortened form, i.e. a single run of zeros may be replaced with double colons (e.g. "FFFF:FFFF:FFC0::")
• IPv6: an address within square brackets (e.g. "[FFFF:FFFF:FFC0::]")

Parameters:

mask - the string representation of the subnet mask

Returns:

the subnet mask instance

Throws:

NullPointerException - if mask is null

IllegalArgumentException - if mask is not an acceptable format

fromCidr

public static SubnetMask fromCidr(String cidr)

Returns a SubnetMask object that represents the value of the subnet mask implied by the given CIDR notation. For example:

 SubnetMask.fromCidr("192.168.0.0/23")
 

would return the subnet mask equivalent to "255.255.254.0"

Parameters:

cidr - the CIDR notation

Returns:

the appropriate subnet mask