net.dpml.lang
Class Version

java.lang.Object
  net.dpml.lang.Version

All Implemented Interfaces:

Serializable, Comparable

public final class Version
extends Object
implements Comparable, Serializable

This class is used to hold version information.

The version number is made up of three dot-separated fields:

"major.minor.micro"

The major, minor and micro fields are integer numbers represented in decimal notation and have the following meaning:

• major - When the major version changes (in ex. from "1.5.12" to "2.0.0"), then backward compatibility with previous releases is not granted.
• minor - When the minor version changes (in ex. from "1.5.12" to "1.6.0"), then backward compatibility with previous releases is granted, but something changed in the implementation of the Component. (ie it methods could have been added)
• micro - When the micro version changes (in ex. from "1.5.12" to "1.5.13"), then the the changes are small forward compatible bug fixes or documentation modifications etc.

Version:

1.0.3

Author:

Digital Product Meta Library

See Also:

Serialized Form

Field Summary

static Version

NULL_VERSION Version -1.0.0.

Constructor Summary

Version(int major, int minor, int micro)
Create a new instance of a Version object with the specified version numbers.

Method Summary

int	compareTo(Object o) Compare two versions together according to the Comparable interface.
boolean	complies(Version other) Check this Version against another for compliancy (compatibility).
boolean	equals(Object other) Indicates whether some other object is "equal to" this Version.
boolean	equals(Version other) Check this Version against another for equality.
int	getMajor() Retrieve major component of version.
int	getMicro() Retrieve micro component of version.
int	getMinor() Retrieve minor component of version.
int	hashCode() Add a hashing function to ensure the Version object is treated as expected in hashmaps and sets.
static Version	parse(String version) Parse a version out of a string.
String	toString() Overload toString to report version correctly.

Methods inherited from class java.lang.Object

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

Field Detail

NULL_VERSION

public static final Version NULL_VERSION

Version -1.0.0.

Constructor Detail

Version

public Version(int major,
               int minor,
               int micro)

Create a new instance of a Version object with the specified version numbers.

Parameters:

major - This Version major number.

minor - This Version minor number.

micro - This Version micro number.

Method Detail

parse

public static Version parse(String version)
                     throws NumberFormatException,
                            IllegalArgumentException,
                            NullPointerException

Parse a version out of a string. The version string format is .. where both minor and micro are optional.

Parameters:

version - The input version string

Returns:

the new Version object

Throws:

NumberFormatException - if an error occurs

IllegalArgumentException - if an error occurs

NullPointerException - if the version argument is null.

Since:

4.1

getMajor

public int getMajor()

Retrieve major component of version.

Returns:

the major component of version

Since:

4.1

getMinor

public int getMinor()

Retrieve minor component of version.

Returns:

the minor component of version

Since:

4.1

getMicro

public int getMicro()

Retrieve micro component of version.

Returns:

the micro component of version.

Since:

4.1

equals

public boolean equals(Version other)

Check this Version against another for equality.

If this Version is compatible with the specified one, then true is returned, otherwise false.

Parameters:

other - The other Version object to be compared with this for equality.

Returns:

true if this Version is compatible with the specified one

Since:

4.1

equals

public boolean equals(Object other)

Indicates whether some other object is "equal to" this Version. Returns true if the other object is an instance of Version and has the same major, minor, and micro components.

Overrides:

equals in class Object

Parameters:

other - an Object value

Returns:

true if the other object is equal to this Version

hashCode

public int hashCode()

Add a hashing function to ensure the Version object is treated as expected in hashmaps and sets. NOTE: any time the equals() is overridden, hashCode() should also be overridden.

Overrides:

hashCode in class Object

Returns:

the hashCode

complies

public boolean complies(Version other)

Check this Version against another for compliancy (compatibility).

If this Version is compatible with the specified one, then true is returned, otherwise false. Be careful when using this method since, in example, version 1.3.7 is compliant to version 1.3.6, while the opposite is not.

The following example displays the expected behaviour and results of version.

 final Version v1 = new Version( 1, 3, 6 );
 final Version v2 = new Version( 1, 3, 7 );
 final Version v3 = new Version( 1, 4, 0 );
 final Version v4 = new Version( 2, 0, 1 );

 assert(   v1.complies( v1 ) );
 assert( ! v1.complies( v2 ) );
 assert(   v2.complies( v1 ) );
 assert( ! v1.complies( v3 ) );
 assert(   v3.complies( v1 ) );
 assert( ! v1.complies( v4 ) );
 assert( ! v4.complies( v1 ) );
 

Parameters:

other - The other Version object to be compared with this for compliancy (compatibility).

Returns:

true if this Version is compatible with the specified one

toString

public String toString()

Overload toString to report version correctly.

Overrides:

toString in class Object

Returns:

the dot seperated version string

compareTo

public int compareTo(Object o)
              throws NullPointerException

Compare two versions together according to the Comparable interface.

Specified by:

compareTo in interface Comparable

Parameters:

o - the other object

Returns:

number indicating relative value (-1, 0, 1)

Throws:

NullPointerException - if the argument is null.