Interface Elements

public interface Elements
Utility methods for operating on program elements.

Compatibility Note: Methods may be added to this interface in future releases of the platform.

Since:
1.6
See Also:

  • Method Details

    • getPackageElement

      PackageElement getPackageElement(CharSequence name)
      Returns a package given its fully qualified name if the package is uniquely determinable in the environment. If running with modules, packages of the given name are searched in a two-stage process: If this process leads to a list with a single element, the single element is returned, otherwise null is returned.
      Parameters:
      name - fully qualified package name, or an empty string for an unnamed package
      Returns:
      the specified package, or null if no package can be uniquely determined.

    • getPackageElement

      default PackageElement getPackageElement(ModuleElement module, CharSequence name)
      Returns a package given its fully qualified name, as seen from the given module.
      Implementation Requirements:
      The default implementation of this method returns null.
      Parameters:
      module - module relative to which the lookup should happen
      name - fully qualified package name, or an empty string for an unnamed package
      Returns:
      the specified package, or null if it cannot be found
      Since:
      9
      See Also:

    • getAllPackageElements

      default Set<? extends PackageElement> getAllPackageElements(CharSequence name)
      Returns all package elements with the given canonical name. There may be more than one package element with the same canonical name if the package elements are in different modules.
      Implementation Requirements:
      The default implementation of this method calls getAllModuleElements and stores the result. If the set of modules is empty, getPackageElement(name) is called passing through the name argument. If getPackageElement(name) is null, an empty set of package elements is returned; otherwise, a single-element set with the found package element is returned. If the set of modules is nonempty, the modules are iterated over and any non-null results of getPackageElement(module, name) are accumulated into a set. The set is then returned.
      Parameters:
      name - the canonical name
      Returns:
      the package elements, or an empty set if no package with the name can be found
      Since:
      9
      See Also:

    • getTypeElement

      TypeElement getTypeElement(CharSequence name)
      Returns a type element given its canonical name if the type element is uniquely determinable in the environment. If running with modules, type elements of the given name are searched in a two-stage process: If this process leads to a list with a single element, the single element is returned, otherwise null is returned.
      Parameters:
      name - the canonical name
      Returns:
      the named type element, or null if no type element can be uniquely determined.

    • getTypeElement

      default TypeElement getTypeElement(ModuleElement module, CharSequence name)
      Returns a type element given its canonical name, as seen from the given module.
      Implementation Requirements:
      The default implementation of this method returns null.
      Parameters:
      module - module relative to which the lookup should happen
      name - the canonical name
      Returns:
      the named type element, or null if it cannot be found
      Since:
      9
      See Also:

    • getAllTypeElements

      default Set<? extends TypeElement> getAllTypeElements(CharSequence name)
      Returns all type elements with the given canonical name. There may be more than one type element with the same canonical name if the type elements are in different modules.
      Implementation Requirements:
      The default implementation of this method calls getAllModuleElements and stores the result. If the set of modules is empty, getTypeElement(name) is called passing through the name argument. If getTypeElement(name) is null, an empty set of type elements is returned; otherwise, a single-element set with the found type element is returned. If the set of modules is nonempty, the modules are iterated over and any non-null results of getTypeElement(module, name) are accumulated into a set. The set is then returned.
      Parameters:
      name - the canonical name
      Returns:
      the type elements, or an empty set if no type with the name can be found
      Since:
      9
      See Also:

    • getModuleElement

      default ModuleElement getModuleElement(CharSequence name)
      Returns a module element given its fully qualified name. If the requested module cannot be found, null is returned. One situation where a module cannot be found is if the environment does not include modules, such as an annotation processing environment configured for a source version without modules.
      Implementation Requirements:
      The default implementation of this method returns null.
      Parameters:
      name - the name, or an empty string for an unnamed module
      Returns:
      the named module element, or null if it cannot be found
      Since:
      9
      See Also:

    • getAllModuleElements

      default Set<? extends ModuleElement> getAllModuleElements()
      Returns all module elements in the current environment. If no modules are present, an empty set is returned. One situation where no modules are present occurs when the environment does not include modules, such as an annotation processing environment configured for a source version without modules.
      API Note:
      When an environment includes modules, both named modules and unnamed modules may be returned.
      Implementation Requirements:
      The default implementation of this method returns an empty set.
      Returns:
      the known module elements, or an empty set if there are no modules
      Since:
      9
      See Also:

    • getElementValuesWithDefaults

      Map<? extends ExecutableElement,? extends AnnotationValue> getElementValuesWithDefaults(AnnotationMirror a)
      Returns the values of an annotation's elements, including defaults.
      Parameters:
      a - annotation to examine
      Returns:
      the values of an annotation's elements, including defaults
      See Also:

    • getDocComment

      String getDocComment(Element e)
      Returns the text of the documentation ("JavaDoc") comment of an element.

      A documentation comment of an element is a particular kind of comment that immediately precedes the element, ignoring white space, annotations and any other comments that are not themselves documentation comments.

      There are two kinds of documentation comments, either based on traditional comments or based on a series of end-of-line comments. For both kinds, the text returned for the documentation comment is a processed form of the comment as it appears in source code, as described below.

      A traditional documentation comment is a traditional comment that begins with "/**", and ends with a separate "*/". (Therefore, such a comment contains at least three "*" characters.) The lines of such a comment are processed as follows:

      • The leading "/**" is removed, as are any immediately following space characters on that line. If all the characters of the line are removed, it makes no contribution to the returned comment.
      • For subsequent lines of the doc comment starting after the initial "/**", if the lines start with zero or more whitespace characters followed by one or more "*" characters, those leading whitespace characters are discarded as are any consecutive "*" characters appearing after the white space or starting the line. Otherwise, if a line does not have a prefix of the described form, the entire line is retained.
      • The trailing "*/" is removed. The line with the trailing" */" also undergoes leading space and "*" character removal as described above.
      • The processed lines are then concatenated together, separated by newline ("\n") characters, and returned.

      An end-of-line documentation comment is a series of adjacent end-of-line comments, each on a line by itself, ignoring any whitespace characters at the beginning of the line, and each beginning with "///". The lines of such a comment are processed as follows:

      • Any leading whitespace and the three initial "/" characters are removed from each line.
      • The lines are shifted left, by removing leading whitespace characters, until the non-blank line with the least leading whitespace characters has no remaining leading whitespace characters.
      • Additional leading whitespace characters and any trailing whitespace characters in each line are preserved.
      • The processed lines are then concatenated together, separated by newline ("\n") characters, and returned. If the last line is not blank, the returned value will not be terminated by a newline character.
      API Note:
      Documentation comments are processed by the standard doclet used by the javadoc tool to generate API documentation.
      Parameters:
      e - the element being examined
      Returns:
      the documentation comment of the element, or null if there is none
      See Java Language Specification:
      3.6 White Space
      3.7 Comments

    • getDocCommentKind

      default Elements.DocCommentKind getDocCommentKind(Element e)
      Returns the kind of the documentation comment for the given element, or null if there is no comment or the kind is not known.
      Implementation Requirements:
      The default implementation of this method returns null.
      Parameters:
      e - the element being examined
      Returns:
      the kind of the documentation comment for the given element, or null if there is no comment or the kind is not known
      Since:
      23

    • isDeprecated

      boolean isDeprecated(Element e)
      Returns true if the element is deprecated, false otherwise.
      Parameters:
      e - the element being examined
      Returns:
      true if the element is deprecated, false otherwise

    • getOrigin

      default Elements.Origin getOrigin(Element e)
      Returns the origin of the given element.

      Note that if this method returns EXPLICIT and the element was created from a class file, then the element may not, in fact, correspond to an explicitly declared construct in source code. This is due to limitations of the fidelity of the class file format in preserving information from source code. For example, at least some versions of the class file format do not preserve whether a constructor was explicitly declared by the programmer or was implicitly declared as the default constructor.

      Implementation Requirements:
      The default implementation of this method returns EXPLICIT.
      Parameters:
      e - the element being examined
      Returns:
      the origin of the given element
      Since:
      9

    • getOrigin

      default Elements.Origin getOrigin(AnnotatedConstruct c, AnnotationMirror a)
      Returns the origin of the given annotation mirror. An annotation mirror is mandated if it is an implicitly declared container annotation used to hold repeated annotations of a repeatable annotation interface.

      Note that if this method returns EXPLICIT and the annotation mirror was created from a class file, then the element may not, in fact, correspond to an explicitly declared construct in source code. This is due to limitations of the fidelity of the class file format in preserving information from source code. For example, at least some versions of the class file format do not preserve whether an annotation was explicitly declared by the programmer or was implicitly declared as a container annotation.

      Implementation Requirements:
      The default implementation of this method returns EXPLICIT.
      Parameters:
      c - the construct the annotation mirror modifies
      a - the annotation mirror being examined
      Returns:
      the origin of the given annotation mirror
      See Java Language Specification:
      9.6.3 Repeatable Annotation Interfaces
      9.7.5 Multiple Annotations of the Same Interface
      Since:
      9

    • getOrigin

      default Elements.Origin getOrigin(ModuleElement m, ModuleElement.Directive directive)
      Returns the origin of the given module directive.

      Note that if this method returns EXPLICIT and the module directive was created from a class file, then the module directive may not, in fact, correspond to an explicitly declared construct in source code. This is due to limitations of the fidelity of the class file format in preserving information from source code. For example, at least some versions of the class file format do not preserve whether a uses directive was explicitly declared by the programmer or was added as a synthetic construct.

      Note that an implementation may not be able to reliably determine the origin status of the directive if the directive is created from a class file due to limitations of the fidelity of the class file format in preserving information from source code.

      Implementation Requirements:
      The default implementation of this method returns EXPLICIT.
      Parameters:
      m - the module of the directive
      directive - the module directive being examined
      Returns:
      the origin of the given module directive
      Since:
      9

    • isBridge

      default boolean isBridge(ExecutableElement e)
      Returns true if the executable element is a bridge method, false otherwise.
      Implementation Requirements:
      The default implementation of this method returns false.
      Parameters:
      e - the executable being examined
      Returns:
      true if the executable element is a bridge method, false otherwise
      Since:
      9

    • getBinaryName

      Name getBinaryName(TypeElement type)
      Returns the binary name of a type element.
      Parameters:
      type - the type element being examined
      Returns:
      the binary name of a type element
      See Java Language Specification:
      13.1 The Form of a Binary
      See Also:

    • getPackageOf

      PackageElement getPackageOf(Element e)
      Returns the package of an element. The package of a package is itself. The package of a module is null. The package of a top-level class or interface is its enclosing package. Otherwise, the package of an element is equal to the package of the enclosing element.
      Parameters:
      e - the element being examined
      Returns:
      the package of an element

    • getModuleOf

      default ModuleElement getModuleOf(Element e)
      Returns the module of an element. The module of a module is itself. If a package has a module as its enclosing element, that module is the module of the package. If the enclosing element of a package is null, null is returned for the package's module. (One situation where a package may have a null module is if the environment does not include modules, such as an annotation processing environment configured for a source version without modules.) Otherwise, the module of an element is equal to the module of the package of the element.
      Implementation Requirements:
      The default implementation of this method returns null.
      Parameters:
      e - the element being examined
      Returns:
      the module of an element
      Since:
      9

    • getAllMembers

      List<? extends Element> getAllMembers(TypeElement type)
      Returns all members of a type element, whether inherited or declared directly. For a class, the result also includes its constructors, but not local or anonymous classes.
      API Note:
      Elements of certain kinds can be isolated using methods in ElementFilter.
      Parameters:
      type - the type being examined
      Returns:
      all members of the type
      See Also:

    • getOutermostTypeElement

      default TypeElement getOutermostTypeElement(Element e)
      Returns the outermost type element an element is contained in if such a containing element exists; otherwise returns null. Modules and packages do not have a containing type element and therefore null is returned for those kinds of elements. A top-level class or interface is its own outermost type element.
      Implementation Requirements:
      The default implementation of this method first checks the kind of the argument. For elements of kind PACKAGE, MODULE, and OTHER, null is returned. For elements of other kinds, the element is examined to see if it is a top-level class or interface. If so, that element is returned; otherwise, the enclosing element chain is followed until a top-level class or interface is found. The element for the eventual top-level class or interface is returned.
      Parameters:
      e - the element being examined
      Returns:
      the outermost type element an element is contained in if such a containing element exists; otherwise returns null
      Since:
      18
      See Also:

    • getAllAnnotationMirrors

      List<? extends AnnotationMirror> getAllAnnotationMirrors(Element e)
      Returns all annotations present on an element, whether directly present or present via inheritance.

      Note that any annotations returned by this method are declaration annotations.

      Parameters:
      e - the element being examined
      Returns:
      all annotations of the element
      See Also:

    • hides

      boolean hides(Element hider, Element hidden)
      Tests whether one type, method, or field hides another.
      Parameters:
      hider - the first element
      hidden - the second element
      Returns:
      true if and only if the first element hides the second
      See Java Language Specification:
      8.4.8 Inheritance, Overriding, and Hiding

    • overrides

      boolean overrides(ExecutableElement overrider, ExecutableElement overridden, TypeElement type)
      Tests whether one method, as a member of a given class or interface, overrides another method. When a non-abstract method overrides an abstract one, the former is also said to implement the latter. As implied by JLS 8.4.8.1, a method does not override itself. The overrides relation is irreflexive.

      In the simplest and most typical usage, the value of the type parameter will simply be the class or interface directly enclosing overrider (the possibly-overriding method). For example, suppose m1 represents the method String.hashCode and m2 represents Object.hashCode. We can then ask whether m1 overrides m2 within the class String (it does):

      assert elements.overrides(m1, m2, elements.getTypeElement("java.lang.String"));
      A more interesting case can be illustrated by the following example in which a method in class A does not override a like-named method in interface B:
      class A { public void m() {} }
      interface B { void m(); }
      ...
      m1 = ...; // A.m
      m2 = ...; // B.m
      assert ! elements.overrides(m1, m2, elements.getTypeElement("A"));
      When viewed as a member of a third class C, however, the method in A does override the one in B:
      class C extends A implements B {}
      ...
      assert elements.overrides(m1, m2, elements.getTypeElement("C"));
      Consistent with the usage of the @Override annotation, if an interface declares a method override-equivalent to a public method of java.lang.Object, such a method of the interface is regarded as overriding the corresponding Object method; for example: 
      interface I {
  @Override
  String toString();
}
...
assert elements.overrides(elementForItoString,
                          elementForObjecttoString,
                          elements.getTypeElement("I"));
      Parameters:
      overrider - the first method, possible overrider
      overridden - the second method, possibly being overridden
      type - the class or interface of which the first method is a member
      Returns:
      true if and only if the first method overrides the second
      See Java Language Specification:
      8.4.8 Inheritance, Overriding, and Hiding
      9.4.1 Inheritance and Overriding

    • getConstantExpression

      String getConstantExpression(Object value)
      Returns the text of a constant expression representing a primitive value or a string. The text returned is in a form suitable for representing the value in source code.
      Parameters:
      value - a primitive value or string
      Returns:
      the text of a constant expression
      Throws:
      IllegalArgumentException - if the argument is not a primitive value or string
      See Also:

    • printElements

      void printElements(Writer w, Element... elements)
      Prints a representation of the elements to the given writer in the specified order. The main purpose of this method is for diagnostics. The exact format of the output is not specified and is subject to change.
      Parameters:
      w - the writer to print the output to
      elements - the elements to print

    • getName

      Name getName(CharSequence cs)
      Returns a name with the same sequence of characters as the argument.
      Parameters:
      cs - the character sequence to return as a name
      Returns:
      a name with the same sequence of characters as the argument

    • isFunctionalInterface

      boolean isFunctionalInterface(TypeElement type)
      Returns true if the type element is a functional interface, false otherwise.
      Parameters:
      type - the type element being examined
      Returns:
      true if the type element is a functional interface, false otherwise
      See Java Language Specification:
      9.8 Functional Interfaces
      Since:
      1.8

    • isAutomaticModule

      default boolean isAutomaticModule(ModuleElement module)
      Returns true if the module element is an automatic module, false otherwise.
      Implementation Requirements:
      The default implementation of this method returns false.
      Parameters:
      module - the module element being examined
      Returns:
      true if the module element is an automatic module, false otherwise
      See Java Language Specification:
      7.7.1 Dependences
      Since:
      17

    • getEnumConstantBody

      default TypeElement getEnumConstantBody(VariableElement enumConstant)
      Returns the class body of an enum constant if the argument is an enum constant declared with an optional class body, null otherwise.
      Implementation Requirements:
      The default implementation of this method throws UnsupportedOperationException if the argument is an enum constant and throws an IllegalArgumentException if it is not.
      Parameters:
      enumConstant - an enum constant
      Returns:
      the class body of an enum constant if the argument is an enum constant declared with an optional class body, null otherwise
      Throws:
      IllegalArgumentException - if the argument is not an enum constant
      See Java Language Specification:
      8.9.1 Enum Constants
      Since:
      22

    • recordComponentFor

      default RecordComponentElement recordComponentFor(ExecutableElement accessor)
      Returns the record component for the given accessor. Returns null if the given method is not a record component accessor.
      Implementation Requirements:
      The default implementation of this method checks if the element enclosing the accessor has kind RECORD, if that is the case, then all the record components of the accessor's enclosing element are isolated by invoking ElementFilter.recordComponentsIn(Iterable). If the accessor of at least one of the record components retrieved happens to be equal to the accessor passed as a parameter to this method, then that record component is returned, in any other case null is returned.
      Parameters:
      accessor - the method for which the record component should be found.
      Returns:
      the record component, or null if the given method is not a record component accessor
      Since:
      16

    • isCanonicalConstructor

      default boolean isCanonicalConstructor(ExecutableElement e)
      Returns true if the executable element can be determined to be a canonical constructor of a record, false otherwise. Note that in some cases there may be insufficient information to determine if a constructor is a canonical constructor, such as if the executable element is built backed by a class file. In such cases, false is returned.
      Implementation Requirements:
      The default implementation of this method unconditionally returns false.
      Parameters:
      e - the executable being examined
      Returns:
      true if the executable element can be determined to be a canonical constructor of a record, false otherwise
      See Java Language Specification:
      8.10.4.1 Normal Canonical Constructors
      Since:
      20

    • isCompactConstructor

      default boolean isCompactConstructor(ExecutableElement e)
      Returns true if the executable element can be determined to be a compact constructor of a record, false otherwise. By definition, a compact constructor is also a canonical constructor. Note that in some cases there may be insufficient information to determine if a constructor is a compact constructor, such as if the executable element is built backed by a class file. In such cases, false is returned.
      Implementation Requirements:
      The default implementation of this method unconditionally returns false.
      Parameters:
      e - the executable being examined
      Returns:
      true if the executable element can be determined to be a compact constructor of a record, false otherwise
      See Java Language Specification:
      8.10.4.2 Compact Canonical Constructors
      Since:
      20

    • getFileObjectOf

      default JavaFileObject getFileObjectOf(Element e)
      Returns the file object for this element or null if there is no such file object.

      The returned file object is for the reference representation of the information used to construct the element. For example, if during compilation or annotation processing, a source file for class Foo is compiled into a class file, the file object returned for the element representing Foo would be for the source file and not for the class file.

      An implementation may choose to not support the functionality of this method, in which case UnsupportedOperationException is thrown.

      In the context of annotation processing, a non-null value is returned if the element was included as part of the initial inputs or the containing file was created during the run of the annotation processing tool. Otherwise, a null may be returned. In annotation processing, if a class file is created, that class file can serve as the reference representation for elements.

      If it has a file object, the file object for a package will be a package-info file. A package may exist and not have any package-info file even if the package is (implicitly) created during an annotation processing run from the creation of source or class files in that package. An unnamed package will have a null file since it cannot be declared in a compilation unit.

      If it has a file object, the file object for a module will be a module-info file. An unnamed module will have a null file since it cannot be declared in a compilation unit. An automatic module will have a null file since it is implicitly declared.

      If it has a file object, the file object for a top-level public class or interface will be a source or class file corresponding to that class or interface. In this case, typically the leading portion of the name of the file will match the name of the class or interface. A single compilation unit can define multiple top-level classes and interfaces, such as a primary public class or interfaces whose name corresponds to the file name and one or more auxiliary classes or interfaces whose names do not correspond to the file name. If a source file is providing the reference representation of an auxiliary class or interface, the file for the primary class is returned. (An auxiliary class or interface can also be defined in a package-info source file, in which case the file for the package-info file is returned.) If a class file is providing the reference representation of an auxiliary class or interface, the separate class file for the auxiliary class is returned.

      For a nested class or interface, if it has a file object:

      • if a source file is providing the reference representation, the file object will be that of the outermost enclosing class or interface
      • if a class file is providing the reference representation, the file object will be that of the nested class or interface itself

      For other lexically enclosed elements, such as variables, methods, and constructors, if they have a file object, the file object will be the object associated with the enclosing element of the lexically enclosed element.

      Implementation Requirements:
      The default implementation unconditionally throws UnsupportedOperationException.
      Parameters:
      e - the element to find a file object for
      Returns:
      the file object for this element or null if there is no such file object
      Throws:
      UnsupportedOperationException - if this functionality is not supported
      Since:
      18