com.hp.util.ip

Class VlanId

java.lang.Object

com.hp.util.ip.VlanId

All Implemented Interfaces:

Comparable<VlanId>

public class VlanId
extends Object
implements Comparable<VlanId>

Represents a VLAN Identifier, which is an unsigned, 12-bit value. There are two special values:

• VlanId.NONE - denoting the absence of a VLAN ID
• VlanId.PRESENT - denoting the presence of a VLAN ID, without specifying its value

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

Instances of this class are immutable, making them inherently threadsafe.

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 identifiers is presented in an intuitive order.

Author:

Simon Hunt

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_VALUE The maximum permissible value (4095).
static int	MIN_VALUE The minimum permissible value (0).
static VlanId	NONE A special value denoting the absence of a VLAN ID.
static VlanId	PRESENT A special value denoting the presence of a VLAN ID, without defining the specific value.

Method Summary

Methods

Modifier and Type	Method and Description
int	compareTo(VlanId o)
boolean	equals(Object o)
int	hashCode()
void	intoBuffer(ByteBuffer b) Writes this VLAN ID into the given ByteBuffer at the buffer's (as a two byte value with the top four bits set to 0).
static String	specialName(VlanId v) Returns the logical name of the given VLAN ID if it is a special value; null otherwise.
int	toInt() Returns the Virtual Network Identifier represented as an integer.
String	toString() Returns a string representation of this VLAN ID, as a decimal number.
static VlanId	valueFrom(ByteBuffer buffer) Reads 2 bytes from the specified byte buffer and creates a VLAN ID entity from the value.
static VlanId	valueOf(int value) Returns a VLAN ID instance representing the value given by the specified integer.
static VlanId	valueOf(String value) Returns a VLAN ID instance representing the value given by the specified string.
static VlanId	vlan(int value) A convenience method that simply delegates to valueOf(int).

Methods inherited from class java.lang.Object

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

Field Detail

MAX_VALUE

public static final int MAX_VALUE

The maximum permissible value (4095).

See Also:

Constant Field Values

MIN_VALUE

public static final int MIN_VALUE

The minimum permissible value (0).

See Also:

Constant Field Values

NONE

public static final VlanId NONE

A special value denoting the absence of a VLAN ID.

PRESENT

public static final VlanId PRESENT

A special value denoting the presence of a VLAN ID, without defining the specific value.

Method Detail

toString

public String toString()

Returns a string representation of this VLAN ID, as a decimal number.

Overrides:

toString in class Object

Returns:

the VLAN ID as a string

toInt

public int toInt()

Returns the Virtual Network Identifier represented as an integer.

Returns:

the VNI encoded as an int

intoBuffer

public void intoBuffer(ByteBuffer b)

Writes this VLAN ID into the given ByteBuffer at the buffer's (as a two byte value with the top four bits set to 0).

Parameters:

b - the byte buffer to write into

valueOf

public static VlanId valueOf(int value)

Returns a VLAN ID instance representing the value given by the specified integer.

Parameters:

value - the value

Returns:

the VLAN ID for the given value

Throws:

IllegalArgumentException - if value is not u12

vlan

public static VlanId vlan(int value)

A convenience method that simply delegates to valueOf(int).

Included so that this method may be statically imported, such that it is easy to express VLAN IDs in code:

     import static com.hp.util.ip.VlanId.vlan;
     ...
     VlanId v = vlan(3);
 

Parameters:

value - the value

Returns:

the VLAN ID for the given value

Throws:

IllegalArgumentException - if value is not u12

valueOf

public static VlanId valueOf(String value)

Returns a VLAN ID instance representing the value given by the specified string. Recognized formats are decimal or hex (prefixed with "0x") strings, or the special values:

• "PRESENT"
• "NONE"

The following examples return a VLAN ID of 23:

     VlanId v1 = VlanId.valueOf("23");
     VlanId v2 = VlanId.valueOf("0x17");
 

Parameters:

value - a string representing a VLAN ID number

Returns:

the VLAN ID for the given value

Throws:

NullPointerException - if value is null

IllegalArgumentException - if value is not parsable as a u12 value

valueFrom

public static VlanId valueFrom(ByteBuffer buffer)

Reads 2 bytes from the specified byte buffer and creates a VLAN ID entity from the value.

Parameters:

buffer - byte buffer from which to read the bytes

Returns:

a VLAN ID instance

Throws:

BufferUnderflowException - if the buffer does not have 2 bytes remaining

IllegalArgumentException - if the read value is not u12

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(VlanId o)

Specified by:

compareTo in interface Comparable<VlanId>

specialName

public static String specialName(VlanId v)

Returns the logical name of the given VLAN ID if it is a special value; null otherwise.

Parameters:

v - the value

Returns:

its logical name