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org.activemq.service
Class MessageIdentity  

java.lang.Object
  org.activemq.service.MessageIdentity

All Implemented Interfaces:

java.lang.Comparable, java.io.Serializable

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public class MessageIdentity

extends java.lang.Object

implements java.lang.Comparable, java.io.Serializable

Represents a message identity, either by using a unique message number, which is ordered and must not be zero or by specifying the String messageID.

Typically a client accessing the MessageStore may have one or the other. Depending on which one is specified the other value may be filled in by operations on the MessageStore

Version:

$Revision: 1.1.1.1 $

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Field Summary
private  java.lang.String	messageID
private  java.lang.Object	sequenceNumber
private static long	serialVersionUID

 

Constructor Summary

MessageIdentity()

MessageIdentity(java.lang.String messageID)

MessageIdentity(java.lang.String messageID, java.lang.Object sequenceNumber)

 

Method Summary
int	compareTo(java.lang.Object object)           Compares this object with another, and returns a numerical result based on the comparison.
boolean	equals(MessageIdentity that)
boolean	equals(java.lang.Object that)           Determine whether this Object is semantically equal to another Object.
java.lang.String	getMessageID()
java.lang.Object	getSequenceNumber()
int	hashCode()           Get a value that represents this Object, as uniquely as possible within the confines of an int.
void	setMessageID(java.lang.String messageID)
void	setSequenceNumber(java.lang.Object sequenceNumber)
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

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

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messageID

private java.lang.String messageID

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sequenceNumber

private java.lang.Object sequenceNumber

Constructor Detail

MessageIdentity

public MessageIdentity()

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MessageIdentity

public MessageIdentity(java.lang.String messageID)

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MessageIdentity

public MessageIdentity(java.lang.String messageID,
                       java.lang.Object sequenceNumber)

Method Detail

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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equals

public boolean equals(java.lang.Object that)

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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equals

public boolean equals(MessageIdentity that)

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compareTo

public int compareTo(java.lang.Object object)

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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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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getMessageID

public java.lang.String getMessageID()

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setMessageID

public void setMessageID(java.lang.String messageID)

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getSequenceNumber

public java.lang.Object getSequenceNumber()

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setSequenceNumber

public void setSequenceNumber(java.lang.Object sequenceNumber)

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

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