org.apache.sis.util

## Class Version

- Object
- - Version

- All Implemented Interfaces:
    Serializable, CharSequence, Comparable<Version>

      public class Version
      extends Object
      implements CharSequence, Comparable<Version>, Serializable

  Holds a version number as a sequence of strings separated by either a dot or a dash. The first three strings, usually numbers, are called respectively major, minor and revision. For example a version code such as `"6.11.2"` will have major number 6, minor number 11 and revision number 2. Alternatively a version code such as `"3.18-SNAPSHOT"` will have major version number 3, minor version number 18 and revision string "SNAPSHOT".

  This class provides methods for performing comparisons of `Version` objects where major, minor and revision parts are compared as numbers when possible, or as strings otherwise.

  Immutability and thread safety
  This class is immutable and thus inherently thread-safe. Subclasses may or may not be immutable, at implementation choice. But implementors are encouraged to make sure that subclasses remain immutable for more predictable behavior.
  Since:
    0.3
  See Also:
    Serialized Form

  Defined in the `sis-utility` module

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Version` | `SIS` The version of this Apache SIS distribution.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `Version(String version)` Creates a new version object from the supplied string.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `char` | `charAt(int index)` Returns the `char` value at the specified index.
    `int` | `compareTo(Version other)` Compares this version with an other version object.
    `int` | `compareTo(Version other, int limit)` Compares this version with an other version object, up to the specified limit.
    `boolean` | `equals(Object other)` Compare this version string with the specified object for equality.
    `Comparable<?>` | `getMajor()` Returns the major version number.
    `Comparable<?>` | `getMinor()` Returns the minor version number.
    `Comparable<?>` | `getRevision()` Returns the revision number.
    `int` | `hashCode()` Returns a hash code value for this version.
    `int` | `length()` Returns the length of the version string.
    `CharSequence` | `subSequence(int start, int end)` Returns a new version string that is a subsequence of this sequence.
    `String` | `toString()` Returns the version string.
    `static Version` | `valueOf(int... components)` Returns an instance for the given integer values.

    - ### Methods inherited from class Object

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

    - ### Methods inherited from interface CharSequence

      `chars, codePoints`

- - ### Field Detail

    - #### SIS

          public static final Version SIS

      The version of this Apache SIS distribution.

  - ### Constructor Detail

    - #### Version

          public Version(String version)

      Creates a new version object from the supplied string.
      Parameters:
        `version` - the version as a string.

  - ### Method Detail

    - #### valueOf

          public static Version valueOf(int... components)

      Returns an instance for the given integer values. The `components` array must contain at least 1 element, where:
      - The first element is the major number.
      - The second element (if any) is the minor number.
      - The third element (if any) is the revision number.
      - Other elements (if any) will be appended to the `string value`.
      Parameters:
        `components` - the major number, optionally followed by minor, revision or other numbers.
      Returns:
        a new or existing instance of `Version` for the given numbers.
      Since:
        0.4

    - #### getMajor

          public Comparable<?> getMajor()

      Returns the major version number. This method returns an `Integer` if possible, or a `String` otherwise.
      Returns:
        the major version number.

    - #### getMinor

          public Comparable<?> getMinor()

      Returns the minor version number. This method returns an `Integer` if possible, or a `String` otherwise. If there is no minor version number, then this method returns `null`.
      Returns:
        the minor version number, or `null` if none.

    - #### getRevision

          public Comparable<?> getRevision()

      Returns the revision number. This method returns an `Integer` if possible, or a `String` otherwise. If there is no revision number, then this method returns `null`.
      Returns:
        the revision number, or `null` if none.

    - #### compareTo

          public int compareTo(Version other,
                               int limit)

      Compares this version with an other version object, up to the specified limit. A limit of 1 compares only the major version number. A limit of 2 compares the major and minor version numbers, etc. The comparisons are performed as `Integer` object if possible, or as `String` otherwise.
      Parameters:
        `other` - the other version object to compare with.
        `limit` - the maximum number of components to compare.
      Returns:
        a negative value if this version is lower than the supplied version, a positive value if it is higher, or 0 if they are equal.

    - #### compareTo

          public int compareTo(Version other)

      Compares this version with an other version object. This method performs the same comparison than `compareTo(Version, int)` with no limit.
      Specified by:
        `compareTo` in interface `Comparable<Version>`
      Parameters:
        `other` - the other version object to compare with.
      Returns:
        a negative value if this version is lower than the supplied version, a positive value if it is higher, or 0 if they are equal.

    - #### equals

          public boolean equals(Object other)

      Compare this version string with the specified object for equality. Two version are considered equal if `compareTo(other) == 0`.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `other` - the object to compare with this version for equality.

    - #### length

          public int length()

      Returns the length of the version string.
      Specified by:
        `length` in interface `CharSequence`

    - #### charAt

          public char charAt(int index)

      Returns the `char` value at the specified index.
      Specified by:
        `charAt` in interface `CharSequence`

    - #### subSequence

          public CharSequence subSequence(int start,
                                          int end)

      Returns a new version string that is a subsequence of this sequence.
      Specified by:
        `subSequence` in interface `CharSequence`

    - #### toString

          public String toString()

      Returns the version string. This is the string specified at construction time.
      Specified by:
        `toString` in interface `CharSequence`
      Overrides:
        `toString` in class `Object`

    - #### hashCode

          public int hashCode()

      Returns a hash code value for this version.
      Overrides:
        `hashCode` in class `Object`

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