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com.ubermq.chord
Class BoundedChordIdentifier  view BoundedChordIdentifier download BoundedChordIdentifier.java

java.lang.Object
  extended bycom.ubermq.chord.BoundedChordIdentifier
All Implemented Interfaces:
ChordIdentifier, java.lang.Comparable, java.io.Serializable

public class BoundedChordIdentifier
extends java.lang.Object
implements ChordIdentifier


Nested Class Summary
private static class BoundedChordIdentifier.MyFactory
           
 
Field Summary
private static java.util.Map factories
           
private static java.util.regex.Pattern modPattern
          My regex pattern matcher for converting toString representations.
private  int modulo
           
static long serialVersionUID
           
private static java.security.SecureRandom sr
           
private  int value
           
 
Constructor Summary
(package private) BoundedChordIdentifier(int modulo)
           
(package private) BoundedChordIdentifier(int value, int modulo)
           
(package private) BoundedChordIdentifier(java.lang.Object o, int modulo)
           
(package private) BoundedChordIdentifier(java.lang.String value, int modulo)
           
 
Method Summary
 int compareTo(java.lang.Object o)
          Compares this object with another, and returns a numerical result based on the comparison.
 boolean equals(java.lang.Object o)
          Determine whether this Object is semantically equal to another Object.
 ChordIdentifierFactory factory()
          Provides the factory instance used to create this identifier, so that new identifiers can be easily created from existing ones.
static ChordIdentifierFactory getFactory(int bits)
          Returns the bitwise identifier factory given a keyspace in bits.
 int hashCode()
          Get a value that represents this Object, as uniquely as possible within the confines of an int.
 ChordIdentifier next()
          Returns the next chord identifier in the identifier sequence.
 ChordIdentifier next(long l)
          Returns the chord identifier that is l after this one.
 ChordIdentifier nextFinger(int i)
          Returns the identifier for the ith finger for this identifier.
 double normal()
          Returns the normalized representation of this identifier relative to other identifiers.
 java.lang.String toString()
          Convert this Object to a human-readable String.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

sr

private static java.security.SecureRandom sr

factories

private static final java.util.Map factories

serialVersionUID

public static final long serialVersionUID
See Also:
Constant Field Values

modPattern

private static final java.util.regex.Pattern modPattern
My regex pattern matcher for converting toString representations.


modulo

private final int modulo

value

private final int value
Constructor Detail

BoundedChordIdentifier

BoundedChordIdentifier(java.lang.String value,
                       int modulo)

BoundedChordIdentifier

BoundedChordIdentifier(int value,
                       int modulo)

BoundedChordIdentifier

BoundedChordIdentifier(int modulo)

BoundedChordIdentifier

BoundedChordIdentifier(java.lang.Object o,
                       int modulo)
Method Detail

getFactory

public static ChordIdentifierFactory getFactory(int bits)
Returns the bitwise identifier factory given a keyspace in bits. This provides for 2^bits unique identifier values.


hashCode

public int hashCode()
Description copied from class: java.lang.Object
Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

  • Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
  • It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in java.util.Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)


compareTo

public int compareTo(java.lang.Object o)
Description copied from interface: java.lang.Comparable
Compares this object with another, and returns a numerical result based on the comparison. If the result is negative, this object sorts less than the other; if 0, the two are equal, and if positive, this object sorts greater than the other. To translate this into boolean, simply perform o1.compareTo(o2) <op> 0, where op is one of <, <=, =, !=, >, or >=.

You must make sure that the comparison is mutual, ie. sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) (where sgn() is defined as -1, 0, or 1 based on the sign). This includes throwing an exception in either direction if the two are not comparable; hence, compareTo(null) should always throw an Exception.

You should also ensure transitivity, in two forms: x.compareTo(y) > 0 && y.compareTo(z) > 0 implies x.compareTo(z) > 0; and x.compareTo(y) == 0 implies x.compareTo(z) == y.compareTo(z).

Specified by:
compareTo in interface java.lang.Comparable

equals

public boolean equals(java.lang.Object o)
Description copied from class: java.lang.Object
Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

  • It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
  • It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
  • It must be reflexive. a.equals(a) must always be true.
  • It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
  • a.equals(null) must be false.
  • It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a java.lang.ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a java.lang.NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, java.util.IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.


toString

public java.lang.String toString()
Description copied from class: java.lang.Object
Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it into System.out.println() 55 and such.

It is typical, but not required, to ensure that this method never completes abruptly with a java.lang.RuntimeException.

This method will be called when performing string concatenation with this object. If the result is null, string concatenation will instead use "null".

The default implementation returns getClass().getName() + "@" + Integer.toHexString(hashCode()).


normal

public double normal()
Returns the normalized representation of this identifier relative to other identifiers. The returned value will be in the interval (0,1).

Specified by:
normal in interface ChordIdentifier

next

public ChordIdentifier next(long l)
Returns the chord identifier that is l after this one. This may be a negative number to go backwards.

Specified by:
next in interface ChordIdentifier

next

public ChordIdentifier next()
Returns the next chord identifier in the identifier sequence.

Specified by:
next in interface ChordIdentifier

nextFinger

public ChordIdentifier nextFinger(int i)
Returns the identifier for the ith finger for this identifier. A finger is defined by the Chord set of algorithms as the identifier that succeeds this identifier by 2i. However, individual identifiers can use other finger computations, as appropriate.

Specified by:
nextFinger in interface ChordIdentifier

factory

public ChordIdentifierFactory factory()
Provides the factory instance used to create this identifier, so that new identifiers can be easily created from existing ones.

Specified by:
factory in interface ChordIdentifier