ants.core
Class TypeID

java.lang.Object
  |
  +--ants.core.TypeID

public final class TypeID

extends java.lang.Object

Capsule, CapsuleClass, CodeGroup and Protocol identifiers. This class wraps 128 bit MD5 hashes stored in byte arrays.

See the text file On_IDs.txt for a description of how these IDs are used.

Author:

David Wetherall

Constructor Summary

TypeID(byte[] buf, int offset)
Construct a new TypeID and initialize by deep copy.

Method Summary

int	compare(TypeID t) Compare two TypeIDs
static TypeID	computeFromIDs(TypeID[] ids) Compute an ID from a vector of codeIDs.
boolean	equals(java.lang.Object obj) Compare this TypeID with the given one.
int	hashCode()
TypeID	intern() Intern a TypeID and return its canonical value.
static void	sortArray(TypeID[] ids) Sort an array of TypeIDs.
java.lang.String	toString()
byte[]	unwrap() Unwrap this TypeID, returning the inner byte array.
static TypeID	wrap(byte[] buf) Construct and initialize by shallow copy.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TypeID

public TypeID(byte[] buf,
              int offset)

Construct a new TypeID and initialize by deep copy.

Parameters:

buf - the byte[] to copy into this new TypeID.

offset - offset in buf to copy from

Throws:

java.lang.IndexOutOfBoundsException - if buf is too short

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Compare this TypeID with the given one. The given TypeID must match all 16 bytes.

Overrides:

equals in class java.lang.Object

intern

public TypeID intern()

Intern a TypeID and return its canonical value. The intern table is flow-private.

Returns:

the canonical version of this TypeID.

compare

public int compare(TypeID t)

Compare two TypeIDs

Returns:

-1 (this < t), 0 (this.equals(t), 1 (this > t)

sortArray

public static void sortArray(TypeID[] ids)

Sort an array of TypeIDs. Good for short vectors only -- uses insertion sort. Sorts the array inline.

computeFromIDs

public static TypeID computeFromIDs(TypeID[] ids)

Compute an ID from a vector of codeIDs.

This is done by computing a multiple-element md5 hash over a sorted list of code ids.

XXX Combine the insertion sort and the id.update() step from this function. Should only have to iterate over the list once.

Returns:

a TypeID representing this vector's ID.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

unwrap

public byte[] unwrap()

Unwrap this TypeID, returning the inner byte array. Does not return a copy, returns the actual array.

Returns:

the byte[] representing this TypeID.

wrap

public static TypeID wrap(byte[] buf)

Construct and initialize by shallow copy. The different notation is meant to emphasize that a complete object is not being created but rather an existing object is being packaged for convenience.

The length of the buf is not checked.

Parameters:

buf - 16-byte byte[] containing an MD5 checksum.