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.