Scala example source code file (Entity.scala)

This example Scala source code file (Entity.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

boolean, collection, compiler, entity, list, memberentity, membertemplateentity, nsc, option, string, templateentity, typeentity, typeparamconstraint

The Entity.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2007-2013 LAMP/EPFL
 * @author Manohar Jonnalagedda
 * @author Gilles Dubochet
 */

package scala.tools.nsc
package doc
package model

import scala.collection._
import base.comment._
import diagram._

/** An entity in a Scaladoc universe. Entities are declarations in the program and correspond to symbols in the
  * compiler. Entities model the following Scala concepts:
  *  - classes and traits;
  *  - objects and package;
  *  - constructors;
  *  - methods;
  *  - values, lazy values, and variables;
  *  - abstract type members and type aliases;
  *  - type and value parameters;
  *  - annotations. */
trait Entity {
  /** The name of the entity. Note that the name does not qualify this entity uniquely; use its `qualifiedName`
    * instead. */
  def name : String

  /** The qualified name of the entity. This is this entity's name preceded by the qualified name of the template
    * of which this entity is a member. The qualified name is unique to this entity. */
  def qualifiedName: String

  /** The template of which this entity is a member. */
  def inTemplate: TemplateEntity

  /** The list of entities such that each is a member of the entity that follows it; the first entity is always this
    * entity, the last the root package entity. */
  def toRoot: List[Entity]

  /** The qualified name of this entity. */
  override def toString = qualifiedName

  /** The Scaladoc universe of which this entity is a member. */
  def universe: Universe

  /** The annotations attached to this entity, if any. */
  def annotations: List[Annotation]

  /** The kind of the entity */
  def kind: String

  /** Whether or not the template was defined in a package object */
  def inPackageObject: Boolean

  /** Indicates whether this entity lives in the types namespace (classes, traits, abstract/alias types) */
  def isType: Boolean
}

object Entity {
  private def isDeprecated(x: Entity) = x match {
    case x: MemberEntity  => x.deprecation.isDefined
    case _                => false
  }
  /** Ordering deprecated things last. */
  implicit lazy val EntityOrdering: Ordering[Entity] =
    Ordering[(Boolean, String)] on (x => (isDeprecated(x), x.name))
}

/** A template, which is either a class, trait, object or package. Depending on whether documentation is available
  * or not, the template will be modeled as a [scala.tools.nsc.doc.model.NoDocTemplate] or a
  * [scala.tools.nsc.doc.model.DocTemplateEntity]. */
trait TemplateEntity extends Entity {

  /** Whether this template is a package (including the root package). */
  def isPackage: Boolean

  /** Whether this template is the root package. */
  def isRootPackage: Boolean

  /** Whether this template is a trait. */
  def isTrait: Boolean

  /** Whether this template is a class. */
  def isClass: Boolean

  /** Whether this template is an object. */
  def isObject: Boolean

  /** Whether documentation is available for this template. */
  def isDocTemplate: Boolean

  /** Whether this template is a case class. */
  def isCaseClass: Boolean

  /** The self-type of this template, if it differs from the template type. */
  def selfType : Option[TypeEntity]
}


/** An entity that is a member of a template. All entities, including templates, are member of another entity
  * except for parameters and annotations. Note that all members of a template are modelled, including those that are
  * inherited and not declared locally. */
trait MemberEntity extends Entity {

  /** The comment attached to this member, if any. */
  def comment: Option[Comment]

  /** The group this member is from */
  def group: String

  /** The template of which this entity is a member. */
  def inTemplate: DocTemplateEntity

  /** The list of entities such that each is a member of the entity that follows it; the first entity is always this
    * member, the last the root package entity. */
  def toRoot: List[MemberEntity]

  /** The templates in which this member has been declared. The first element of the list is the template that contains
    * the currently active declaration of this member, subsequent elements are declarations that have been overriden. If
    * the first element is equal to `inTemplate`, the member is declared locally, if not, it has been inherited. All
    * elements of this list are in the linearization of `inTemplate`. */
  def inDefinitionTemplates: List[TemplateEntity]

  /** The qualified name of the member in its currently active declaration template. */
  def definitionName: String

  /** The visibility of this member. Note that members with restricted visibility may not be modeled in some
    * universes. */
  def visibility: Visibility

  /** The flags that have been set for this entity. The following flags are supported: `implicit`, `sealed`, `abstract`,
    * and `final`. */
  def flags: List[Paragraph]

  /** Some deprecation message if this member is deprecated, or none otherwise. */
  def deprecation: Option[Body]

  /** Some migration warning if this member has a migration annotation, or none otherwise. */
  def migration: Option[Body]

  /** For members representing values: the type of the value returned by this member; for members
    * representing types: the type itself. */
  def resultType: TypeEntity

  /** Whether this member is a method. */
  def isDef: Boolean

  /** Whether this member is a value (this excludes lazy values). */
  def isVal: Boolean

  /** Whether this member is a lazy value. */
  def isLazyVal: Boolean

  /** Whether this member is a variable. */
  def isVar: Boolean

  /** Whether this member is a constructor. */
  def isConstructor: Boolean

  /** Whether this member is an alias type. */
  def isAliasType: Boolean

  /** Whether this member is an abstract type. */
  def isAbstractType: Boolean

  /** Whether this member is abstract. */
  def isAbstract: Boolean

  /** If this symbol is a use case, the useCaseOf will contain the member it was derived from, containing the full
    * signature and the complete parameter descriptions. */
  def useCaseOf: Option[MemberEntity]

  /** If this member originates from an implicit conversion, we set the implicit information to the correct origin */
  def byConversion: Option[ImplicitConversion]

  /** The identity of this member, used for linking */
  def signature: String

  /** Compatibility signature, will be removed from future versions */
  def signatureCompat: String

  /** Indicates whether the member is inherited by implicit conversion */
  def isImplicitlyInherited: Boolean

  /** Indicates whether there is another member with the same name in the template that will take precendence */
  def isShadowedImplicit: Boolean

  /** Indicates whether there are other implicitly inherited members that have similar signatures (and thus they all
   *  become ambiguous) */
  def isAmbiguousImplicit: Boolean

  /** Indicates whether the implicitly inherited member is shadowed or ambiguous in its template */
  def isShadowedOrAmbiguousImplicit: Boolean
}

object MemberEntity {
  // Oh contravariance, contravariance, wherefore art thou contravariance?
  // Note: the above works for both the commonly misunderstood meaning of the line and the real one.
  implicit lazy val MemberEntityOrdering: Ordering[MemberEntity] = Entity.EntityOrdering on (x => x)
}

/** An entity that is parameterized by types */
trait HigherKinded {

  /** The type parameters of this entity. */
  def typeParams: List[TypeParam]
}


/** A template (class, trait, object or package) which is referenced in the universe, but for which no further
  * documentation is available. Only templates for which a source file is given are documented by Scaladoc. */
trait NoDocTemplate extends TemplateEntity {
  def kind =
    if (isClass) "class"
    else if (isTrait) "trait"
    else if (isObject) "object"
    else ""
}

/** An inherited template that was not documented in its original owner - example:
 *  in classpath:  trait T { class C } -- T (and implicitly C) are not documented
 *  in the source: trait U extends T -- C appears in U as a MemberTemplateImpl
 *    -- that is, U has a member for it but C doesn't get its own page */
trait MemberTemplateEntity extends TemplateEntity with MemberEntity with HigherKinded {

  /** The value parameters of this case class, or an empty list if this class is not a case class. As case class value
    * parameters cannot be curried, the outer list has exactly one element. */
  def valueParams: List[List[ValueParam]]

  /** The direct super-type of this template
      e.g: {{{class A extends B[C[Int]] with D[E]}}} will have two direct parents: class B and D
      NOTE: we are dropping the refinement here! */
  def parentTypes: List[(TemplateEntity, TypeEntity)]
}

/** A template (class, trait, object or package) for which documentation is available. Only templates for which
  * a source file is given are documented by Scaladoc. */
trait DocTemplateEntity extends MemberTemplateEntity {

  /** The list of templates such that each is a member of the template that follows it; the first template is always
    * this template, the last the root package entity. */
  def toRoot: List[DocTemplateEntity]

  /** The source file in which the current template is defined and the line where the definition starts, if they exist.
    * A source file exists for all templates, except for those that are generated synthetically by Scaladoc. */
  def inSource: Option[(io.AbstractFile, Int)]

  /** An HTTP address at which the source of this template is available, if it is available. An address is available
    * only if the `docsourceurl` setting has been set. */
  def sourceUrl: Option[java.net.URL]

  /** All class, trait and object templates which are part of this template's linearization, in lineratization order.
    * This template's linearization contains all of its direct and indirect super-classes and super-traits. */
  def linearizationTemplates: List[TemplateEntity]

  /** All instantiated types which are part of this template's linearization, in lineratization order.
    * This template's linearization contains all of its direct and indirect super-types. */
  def linearizationTypes: List[TypeEntity]

  /** All class, trait and object templates for which this template is a *direct* super-class or super-trait.
   *  Only templates for which documentation is available in the universe (`DocTemplateEntity`) are listed. */
  def directSubClasses: List[DocTemplateEntity]

  /** All members of this template. If this template is a package, only templates for which documentation is available
    * in the universe (`DocTemplateEntity`) are listed. */
  def members: List[MemberEntity]

  /** All templates that are members of this template. If this template is a package, only templates for which
    * documentation is available  in the universe (`DocTemplateEntity`) are listed. */
  def templates: List[TemplateEntity with MemberEntity]

  /** All methods that are members of this template. */
  def methods: List[Def]

  /** All values, lazy values and variables that are members of this template. */
  def values: List[Val]

  /** All abstract types that are members of this template. */
  def abstractTypes: List[AbstractType]

  /** All type aliases that are members of this template. */
  def aliasTypes: List[AliasType]

  /** The primary constructor of this class, if it has been defined. */
  def primaryConstructor: Option[Constructor]

  /** All constructors of this class, including the primary constructor. */
  def constructors: List[Constructor]

  /** The companion of this template, or none. If a class and an object are defined as a pair of the same name, the
    * other entity of the pair is the companion. */
  def companion: Option[DocTemplateEntity]

  /** The implicit conversions this template (class or trait, objects and packages are not affected) */
  def conversions: List[ImplicitConversion]

  /** The shadowing information for the implicitly added members */
  def implicitsShadowing: Map[MemberEntity, ImplicitMemberShadowing]

  /** Classes that can be implcitly converted to this class */
  def incomingImplicitlyConvertedClasses: List[(DocTemplateEntity, ImplicitConversion)]

  /** Classes to which this class can be implicitly converted to
      NOTE: Some classes might not be included in the scaladoc run so they will be NoDocTemplateEntities */
  def outgoingImplicitlyConvertedClasses: List[(TemplateEntity, TypeEntity, ImplicitConversion)]

  /** If this template takes place in inheritance and implicit conversion relations, it will be shown in this diagram */
  def inheritanceDiagram: Option[Diagram]

  /** If this template contains other templates, such as classes and traits, they will be shown in this diagram */
  def contentDiagram: Option[Diagram]

  /** Returns the group description taken either from this template or its linearizationTypes */
  def groupDescription(group: String): Option[Body]

  /** Returns the group description taken either from this template or its linearizationTypes */
  def groupPriority(group: String): Int

  /** Returns the group description taken either from this template or its linearizationTypes */
  def groupName(group: String): String
}

/** A trait template. */
trait Trait extends MemberTemplateEntity {
  def kind = "trait"
}

/** A class template. */
trait Class extends MemberTemplateEntity {
  override def kind = "class"
}

/** An object template. */
trait Object extends MemberTemplateEntity {
  def kind = "object"
}

/** A package template. A package is in the universe if it is declared as a package object, or if it
  * contains at least one template. */
trait Package extends DocTemplateEntity {

  /** The package of which this package is a member. */
  def inTemplate: Package

  /** The package such that each is a member of the package that follows it; the first package is always this
    * package, the last the root package. */
  def toRoot: List[Package]

  /** All packages that are member of this package. */
  def packages: List[Package]

  override def kind = "package"
}


/** The root package, which contains directly or indirectly all members in the universe. A universe
  * contains exactly one root package. */
trait RootPackage extends Package


/** A non-template member (method, value, lazy value, variable, constructor, alias type, and abstract type). */
trait NonTemplateMemberEntity extends MemberEntity {
  /** Whether this member is a use case. A use case is a member which does not exist in the documented code.
    * It corresponds to a real member, and provides a simplified, yet compatible signature for that member. */
  def isUseCase: Boolean
}


/** A method (`def`) of a template. */
trait Def extends NonTemplateMemberEntity with HigherKinded {

  /** The value parameters of this method. Each parameter block of a curried method is an element of the list.
    * Each parameter block is a list of value parameters. */
  def valueParams : List[List[ValueParam]]

  def kind = "method"
}


/** A constructor of a class. */
trait Constructor extends NonTemplateMemberEntity {

  /** Whether this is the primary constructor of a class. The primary constructor is defined syntactically as part of
    * the declaration of the class. */
  def isPrimary: Boolean

  /** The value parameters of this constructor. As constructors cannot be curried, the outer list has exactly one
    * element. */
  def valueParams : List[List[ValueParam]]

  def kind = "constructor"
}


/** A value (`val`), lazy val (`lazy val`) or variable (`var`) of a template. */
trait Val extends NonTemplateMemberEntity {
  def kind = "[lazy] value/variable"
}


/** An abstract type member of a template. */
trait AbstractType extends MemberTemplateEntity with HigherKinded {

  /** The lower bound for this abstract type, if it has been defined. */
  def lo: Option[TypeEntity]

  /** The upper bound for this abstract type, if it has been defined. */
  def hi: Option[TypeEntity]

  def kind = "abstract type"
}


/** An type alias of a template. */
trait AliasType extends MemberTemplateEntity with HigherKinded {

  /** The type aliased by this type alias. */
  def alias: TypeEntity

  def kind = "type alias"
}


/** A parameter to an entity. */
trait ParameterEntity {

  def name: String
}


/** A type parameter to a class, trait, or method. */
trait TypeParam extends ParameterEntity with HigherKinded {

  /** The variance of this type parameter. Valid values are "+", "-", and the empty string. */
  def variance: String

  /** The lower bound for this type parameter, if it has been defined. */
  def lo: Option[TypeEntity]

  /** The upper bound for this type parameter, if it has been defined. */
  def hi: Option[TypeEntity]
}


/** A value parameter to a constructor or method. */
trait ValueParam extends ParameterEntity {

  /** The type of this value parameter. */
  def resultType: TypeEntity

  /** The devault value of this value parameter, if it has been defined. */
  def defaultValue: Option[TreeEntity]

  /** Whether this value parameter is implicit. */
  def isImplicit: Boolean
}


/** An annotation to an entity. */
trait Annotation extends Entity {

  /** The class of this annotation. */
  def annotationClass: TemplateEntity

  /** The arguments passed to the constructor of the annotation class. */
  def arguments: List[ValueArgument]

  def kind = "annotation"
}

/** A trait that signals the member results from an implicit conversion */
trait ImplicitConversion {

  /** The source of the implicit conversion*/
  def source: DocTemplateEntity

  /** The result type after the conversion */
  def targetType: TypeEntity

  /** The components of the implicit conversion type parents */
  def targetTypeComponents: List[(TemplateEntity, TypeEntity)]

  /** The entity for the method that performed the conversion, if it's documented (or just its name, otherwise) */
  def convertorMethod: Either[MemberEntity, String]

  /** A short name of the convertion */
  def conversionShortName: String

  /** A qualified name uniquely identifying the convertion (currently: the conversion method's qualified name) */
  def conversionQualifiedName: String

  /** The entity that performed the conversion */
  def convertorOwner: TemplateEntity

  /** The constraints that the transformations puts on the type parameters */
  def constraints: List[Constraint]

  /** The members inherited by this implicit conversion */
  def members: List[MemberEntity]

  /** Is this a hidden implicit conversion (as specified in the settings) */
  def isHiddenConversion: Boolean
}

/** Shadowing captures the information that the member is shadowed by some other members
 *  There are two cases of implicitly added member shadowing:
 *  1) shadowing from a original class member (the class already has that member)
 *     in this case, it won't be possible to call the member directly, the type checker will fail attempting to adapt
 *     the call arguments (or if they fit it will call the original class' method)
 *  2) shadowing from other possible implicit conversions ()
 *     this will result in an ambiguous implicit converion error
 */
trait ImplicitMemberShadowing {
  /** The members that shadow the current entry use .inTemplate to get to the template name */
  def shadowingMembers: List[MemberEntity]

  /** The members that ambiguate this implicit conversion
      Note: for ambiguatingMembers you have the following invariant:
      assert(ambiguatingMembers.foreach(_.byConversion.isDefined) */
  def ambiguatingMembers: List[MemberEntity]

  def isShadowed: Boolean = !shadowingMembers.isEmpty
  def isAmbiguous: Boolean = !ambiguatingMembers.isEmpty
}

/** A trait that encapsulates a constraint necessary for implicit conversion */
trait Constraint

/** A constraint involving a type parameter which must be in scope */
trait ImplicitInScopeConstraint extends Constraint {
  /** The type of the implicit value required */
  def implicitType: TypeEntity

  /** toString for debugging */
  override def toString = "an implicit _: " + implicitType.name + " must be in scope"
}

trait TypeClassConstraint extends ImplicitInScopeConstraint with TypeParamConstraint {
  /** Type class name */
  def typeClassEntity: TemplateEntity

  /** toString for debugging */
  override def toString = typeParamName + " is a class of type " + typeClassEntity.qualifiedName + " (" +
    typeParamName + ": " + typeClassEntity.name + ")"
}

trait KnownTypeClassConstraint extends TypeClassConstraint {
  /** Type explanation, takes the type parameter name and generates the explanation */
  def typeExplanation: (String) => String

  /** toString for debugging */
  override def toString = typeExplanation(typeParamName) + " (" + typeParamName + ": " + typeClassEntity.name + ")"
}

/** A constraint involving a type parameter */
trait TypeParamConstraint extends Constraint {
  /** The type parameter involved */
  def typeParamName: String
}

trait EqualTypeParamConstraint extends TypeParamConstraint {
  /** The rhs */
  def rhs: TypeEntity
  /** toString for debugging */
  override def toString = typeParamName + " is " + rhs.name + " (" + typeParamName + " =:= " + rhs.name + ")"
}

trait BoundedTypeParamConstraint extends TypeParamConstraint {
  /** The lower bound */
  def lowerBound: TypeEntity

  /** The upper bound */
  def upperBound: TypeEntity

  /** toString for debugging */
  override def toString = typeParamName + " is a superclass of " + lowerBound.name + " and a subclass of " +
    upperBound.name + " (" + typeParamName + " >: " + lowerBound.name + " <: " + upperBound.name + ")"
}

trait LowerBoundedTypeParamConstraint extends TypeParamConstraint {
  /** The lower bound */
  def lowerBound: TypeEntity

  /** toString for debugging */
  override def toString = typeParamName + " is a superclass of " + lowerBound.name + " (" + typeParamName + " >: " +
    lowerBound.name + ")"
}

trait UpperBoundedTypeParamConstraint extends TypeParamConstraint {
  /** The lower bound */
  def upperBound: TypeEntity

  /** toString for debugging */
  override def toString = typeParamName + " is a subclass of " + upperBound.name + " (" + typeParamName + " <: " +
    upperBound.name + ")"
}