# Interface VersionConstraint

All Superinterfaces:
  `Describable`

All Known Subinterfaces:
  `MutableVersionConstraint`

public interface VersionConstraint extends Describable
Represents a constraint that is used to match module versions to a dependency. Each of `getPreferredVersion()`, `getRequiredVersion()` and `getStrictVersion()` is represented by a version String, that can be compared against a module version to determine if the version matches.

## Version syntax

Gradle supports different ways of declaring a version String:

- An exact version: e.g. 1.3, 1.3.0-beta3, 1.0-20150201.131010-1
- A Maven-style version range: e.g. [1.0,), [1.1, 2.0), (1.2, 1.5]
  - The '[' and ']' symbols indicate an inclusive bound; '(' and ')' indicate an exclusive bound.
  - When the upper or lower bound is missing, the range has no upper or lower bound.
  - The symbol ']' can be used instead of '(' for an exclusive lower bound, and '[' instead of ')' for exclusive upper bound. e.g "]1.0, 2.0["
- A prefix version range: e.g. 1.+, 1.3.+
  - Only versions exactly matching the portion before the '+' are included.
  - The range '+' on it's own will include any version.
- A latest-status version: e.g. latest.integration, latest.release
  - Will match the highest versioned module with the specified status. See `ComponentMetadata.getStatus()`.
- A Maven SNAPSHOT version identifier: e.g. 1.0-SNAPSHOT, 1.4.9-beta1-SNAPSHOT

## Version ordering

Versions have an implicit ordering. Version ordering is used to:

- Determine if a particular version is included in a range.
- Determine which version is 'newest' when performing conflict resolution.

Versions are ordered based on the following rules:

- Each version is split into it's constituent "parts":
  - The characters [`. - _ +`] are used to separate the different "parts" of a version.
  - Any part that contains both digits and letters is split into separate parts for each: `1a1 == 1.a.1`
  - Only the parts of a version are compared. The actual separator characters are not significant: `1.a.1 == 1-a+1 == 1.a-1 == 1a1`
- The equivalent parts of 2 versions are compared using the following rules:
  - If both parts are numeric, the highest numeric value is higher: `1.1 < 1.2`
  - If one part is numeric, it is considered higher than the non-numeric part: `1.a < 1.1`
  - If both are not numeric, the parts are compared alphabetically, case-sensitive: `1.A < 1.B < 1.a < 1.b`
  - An version with an extra numeric part is considered higher than a version without: `1.1 < 1.1.0`
  - An version with an extra non-numeric part is considered lower than a version without: `1.1.a < 1.1`
- Certain string values have special meaning for the purposes of ordering:
  - The string "dev" is consider lower than any other string part: 1.0-dev < 1.0-alpha < 1.0-rc.
  - The strings "rc", "release" and "final" are considered higher than any other string part (sorted in that order): 1.0-zeta < 1.0-rc < 1.0-release < 1.0-final < 1.0.
  - The string "SNAPSHOT" has no special meaning, and is sorted alphabetically like any other string part: 1.0-alpha < 1.0-SNAPSHOT < 1.0-zeta < 1.0-rc < 1.0.
  - Numeric snapshot versions have no special meaning, and are sorted like any other numeric part: 1.0 < 1.0-20150201.121010-123 < 1.1.

Since:
  4.4

- ## Method Summary

  Modifier and Type
  Method
  Description
  `@Nullable String`
  `getBranch()`
  The branch to select versions from.
  `String`
  `getPreferredVersion()`
  The preferred version of a module (which may be an exact version or a version range).
  `List<String>`
  `getRejectedVersions()`
  Returns the list of versions that this module rejects (which may be exact versions, or ranges, anything that fits into a version string).
  `String`
  `getRequiredVersion()`
  The required version of a module (which may be an exact version or a version range).
  `String`
  `getStrictVersion()`
  The strictly required version of a module (which may be an exact version or a version range).

  ### Methods inherited from interface Describable

  `getDisplayName`

- ## Method Details

  - ### getBranch

    @Nullable String getBranch()
    The branch to select versions from. When not `null` selects only those versions that were built from the specified branch.
    Since:
      4.6

  - ### getRequiredVersion

    String getRequiredVersion()
    The required version of a module (which may be an exact version or a version range). The required version of a module can typically be upgraded during dependency resolution, but not downgraded.
    Returns:
      the required version, or empty string if no required version specified. Never null.

  - ### getPreferredVersion

    String getPreferredVersion()
    The preferred version of a module (which may be an exact version or a version range). The preferred version of a module provides a hint when resolving the version, but will not be honored in the presence of conflicting constraints.
    Returns:
      the preferred version, or empty string if no preferred version specified. Never null.

  - ### getStrictVersion

    String getStrictVersion()
    The strictly required version of a module (which may be an exact version or a version range). The required version of a module is strictly enforced and cannot be upgraded or downgraded during dependency resolution.
    Returns:
      the strict version, or empty string if no required version specified. Never null.

  - ### getRejectedVersions

    List<String> getRejectedVersions()
    Returns the list of versions that this module rejects (which may be exact versions, or ranges, anything that fits into a version string).
    Returns:
      the list of rejected versions