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com.ubermq.chord
Class IntegerChordIdentifier  

java.lang.Object
  com.ubermq.chord.IntegerChordIdentifier

All Implemented Interfaces:

ChordIdentifier, java.lang.Comparable, java.io.Serializable

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public final class IntegerChordIdentifier

extends java.lang.Object

implements ChordIdentifier

A chord identifier that uses a 2^32 size identifier space. This is intended for use with the Java hashCode operation to perform correct object hashing.

If stricter hashing is required, a SHA implementation of this identifier interface could be created fairly simply.

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Field Summary
private  int	id
static int	INTEGER_FINGER_TABLE_SIZE           The default finger table size for this identifier type.
static long	serialVersionUID
private static java.security.SecureRandom	sr
private static ChordIdentifierFactory	theFactory

 

Constructor Summary
(package private)	IntegerChordIdentifier()           Generates a pseudo-random identifier.
(package private)	IntegerChordIdentifier(int hashCode)           Constructs a chord identifier from an integer.
(package private)	IntegerChordIdentifier(java.lang.Object o)           Constructs a chord identifier from the result of the hashCode method on the given object.

 

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()           Returns the chord identifier factory for integer chord identifiers.
int	hashCode()           Get a value that represents this Object, as uniquely as possible within the confines of an int.
int	intValue()           Returns the value of this chord identifier as 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.
ChordIdentifier	previous()           Returns the previous chord identifier in the identifier sequence.
ChordIdentifier	previous(long l)           Returns the chord identifier that is l before this one.
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

id

private int id

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sr

private static java.security.SecureRandom sr

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serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

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INTEGER_FINGER_TABLE_SIZE

public static final int INTEGER_FINGER_TABLE_SIZE

The default finger table size for this identifier type.

See Also:

Constant Field Values

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theFactory

private static final ChordIdentifierFactory theFactory

Constructor Detail

IntegerChordIdentifier

IntegerChordIdentifier(int hashCode)

Constructs a chord identifier from an integer.

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IntegerChordIdentifier

IntegerChordIdentifier(java.lang.Object o)

Constructs a chord identifier from the result of the hashCode method on the given object.

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IntegerChordIdentifier

IntegerChordIdentifier()

Generates a pseudo-random identifier.

Method Detail

getFactory

public static ChordIdentifierFactory getFactory()

Returns the chord identifier factory for integer chord identifiers.

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normal

public double normal()

Description copied from interface: ChordIdentifier

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

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next

public ChordIdentifier next()

Returns the next chord identifier in the identifier sequence.

Specified by:

next in interface ChordIdentifier

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next

public ChordIdentifier next(long l)

Returns the chord identifier that is l after this one.

Specified by:

next in interface ChordIdentifier

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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

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previous

public ChordIdentifier previous()

Returns the previous chord identifier in the identifier sequence.

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previous

public ChordIdentifier previous(long l)

Returns the chord identifier that is l before this one.

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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

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intValue

public int intValue()

Returns the value of this chord identifier as an int.

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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

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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.

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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)

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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()).

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> com >> ubermq >> [ chord overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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